Influence of Morning and Afternoon Exercise on Body Composition and Metabolic Health

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However, the different effects of morning and afternoon exercise on various metabolic indicators remain unclear. Therefore, this study aimed to systematically evaluate and analyze the effect of exercise at various times on body composition, glucose metabolism, and lipid metabolism. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, this study conducted a literature search in electronic databases including PubMed, Embase, and Web of Science. The studies included exercise regimens in the morning, afternoon, or morning and evening and analyzed body weight, body mass index, fat mass, fasting blood glucose, hemoglobin A1c (HbA1c), insulin, or triglycerides. The risk of bias was assessed using the Cochrane tool (Rob2), and publication bias was assessed using funnel plots and Egger tests. Results: Thirteen long-term and five acute studies were analyzed (n = 658 participants). Morning training was more effective in reducing body fat (mean deviation [MD] -0.39, 95% confidence interval [CI] -0.66 to -0.13, ), waist circumference (MD -0.53, 95% CI -1.06 to -0.00, I 2 = 31%, p = 0.05), and HbA1c (MD -0.11, 95% CI -0.19 to -0.03, I 2 = 0%, p = 0.009), whereas afternoon training was better in lowering fasting blood glucose (MD 0.13, 95% CI 0.01 to 0.24, I 2 = 0%, p = 0.03) and triglycerides (MD 0.1, 95% CI 0.02 to 0.18, I 2 = 41%, p = 0.02). Conclusion: Both morning and afternoon training are beneficial for metabolic health; however, their effects differ. Morning training was more likely to reduce body fat, waist circumference, and HbA1c, whereas afternoon exercise was more likely to reduce fasting blood glucose and triglycerides. Incorporating exercise timing into clinical guidelines could enhance the effectiveness of lifestyle interventions for metabolic disorders. Exercise timing Body composition Glucose metabolism Lipid metabolism Metabolic adaptation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Key points Both morning and afternoon exercise offer benefits for metabolic health, but they have different effects. Morning training is more effective at reducing body fat, waist circumference, and HbA1c levels, which are important for long-term blood sugar control. In contrast, afternoon training is better at lowering fasting blood glucose and triglycerides, which can help with short-term blood sugar management and reducing fat in the blood. 1 Introduction With the worldwide increasing incidence of obesity and metabolic diseases such as type 2 diabetes (T2D) and cardiovascular disorders, identifying effective methods for managing weight and improving metabolic health has become essential 1 – 4 . The Global Burden of Disease Group reported in 2017 that “since 1980, the prevalence of obesity has doubled in more than 70 countries and has continuously increased in most other countries 5 .” Over the past 20 years, the prevalence of metabolic diseases such as T2D mellitus (T2DM) has increased by more than 1.5%, hypertension (HTN) by 0.2%, and non-alcoholic fatty liver disease by 0.83% annually 6 . Exercise, as a non-pharmacological strategy 7 – 9 , has been widely acknowledged for its beneficial effects in enhancing body composition 10 , 11 , glucose metabolism, and lipid profiles 12 , 13 . Recently, the effect of exercise timing on metabolic health has been investigated, and the concept of timed exercise was proposed 14 , 15 . Exercise timing may differentially influence metabolic responses. However, these findings remain inconsistent. A recent meta-analysis showed that exercise timing did not affect the acute cardiometabolic response to exercise 16 . In contrast, another meta-analysis indicated no significant difference in metabolic adaptation between morning training (MT) and afternoon training (AT) but demonstrated the superior efficacy of AT in reducing circulating triglyceride (TG) levels 17 . MT is more effective than AT in reducing abdominal fat in healthy women. However, in men, AT increased lipid oxidation compared to MT 18 . Furthermore, exercise-induced increases in blood adrenaline, growth hormone, and interleukin-6 levels promote lipolysis, suggesting that AT is more effective in promoting lipolysis than MT 19 . However, the results of these studies are inconsistent and contradictory, possibly because of differences in the study design, sample size, exercise protocol, and measurement metrics, leaving a substantial gap in the understanding of the optimal exercise timing for metabolic benefits. Therefore, a more comprehensive approach, such as systematic review and meta-analysis are necessary to obtain a better understanding of the effects of timed exercise on body composition, glucose metabolism, and lipid metabolism. This meta-analysis was expanded by including acute studies and additional body composition metrics to provide a deeper understanding of the effects of exercise timing on metabolic health. By synthesizing existing evidence, this study aimed to clarify temporal patterns of exercise and their influence on metabolic health, offering novel insights for individualized exercise interventions. 2 Methods 2.1 Search strategy and data selection This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines 20 . The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD420250619379). A literature search was conducted using electronic databases, such as PubMed, Embase, and Web of Science (WOS). The search ended in March 2025. Only articles published in English were included. The following search strategy was used: (“exercise” or “training” or “sport” or “physical activity” or “athletics” or “workout” or “fitness” or “play” or “movement”) and (“diel rhythm” or “time of day” or “time-of-day” or “exercise timing” or “circadian” or “morning vs afternoon” or “morning vs evening” or “timing” or “morning” or “afternoon” or “evening”). The “randomized controlled trial” filter was applied in PubMed and Embase databases, and the term “clinical trial” was added to the WOS search. The search results were imported into EndNote to organize the references and remove duplicates. 2.2 Eligibility criteria The studies were selected for further analysis based on the following inclusion criteria: (a) The research design included exercise programs that involved morning, afternoon, or morning and evening sessions, as well as morning, afternoon, and evening sessions. (b) Outcome indicators encompassed blood glucose, blood lipids, or body composition. Studies that used animal models or special populations, such as adolescents, pregnant women, and patients with HTN, were excluded. Each article was independently screened and approved based on the inclusion and exclusion criteria. 2.3 Data extraction, conversion, and synthesis The extracted data included: (1) body weight, (2) body mass index (BMI), (3) fat mass, (4) fat-free mass, (5) waist circumference, (6) body fat, (7) fasting blood glucose (FBG), (8) hemoglobin A1c (HbA1c) (%), (9) fasting insulin, (10) insulin resistance (HOMA-IR), (11) TG, (12) total cholesterol (TC), (13) high-density lipoproteins (HDL), (14) and low-density lipoproteins (LDL) in long-term studies. FBG and post-exercise blood glucose levels were included in acute studies. The results were extracted using Origin 2025 when they were shown only in graphs, and the corresponding authors could not be reached. If the studies only presented 95% confidence intervals (CIs), standard deviations (SDs) were calculated using the https://www.math.hkbu.edu.hk/~tongt/papers/median2mean.html website 21 , 22 . When ΔSD was not reported, it was calculated by assuming a correlation coefficient of 0.7, as previously suggested 23 . The meta-analysis progression was carried out using RevMan5.4 software, using the mean difference (MD) as the measurement data-effect indicator. The criteria for heterogeneity were as follows: I 2 50% indicated that the articles had high heterogeneity. The random-effects model was used to analyze articles with high heterogeneity 24 . 2.4 Risk of bias and methodological quality The risk of bias was assessed according to version 2 of the Cochrane tool (RoB2) 25 , which consists of six domains: randomization process, intended interventions, missing outcome data, outcome, reported results, and overall bias. This study used the RoB2 Assessment Form to generate visual representations of the risk of bias to enhance the transparency and comprehension of the risk of bias across the reviewed literature. 2.5 Sensitivity analysis For the sensitivity analysis, the leave-one-out method was used to assess whether any of the included studies had a significant influence on the overall effect. If the leave-one-out test yielded positive results, the effect size of the model was reported, and that particular study was excluded from the analysis. 2.6 Quality assessment Publication bias pertains to the tendency of significant results to be more likely to be published than null results. Publication bias was assessed by visual inspection of funnel plots and the accompanying Egger’s tests 26 . 3 Results 3.1 Description of studies Tables 1 and 2 present qualitative descriptions of the included studies. Thirteen long-term and 5 acute studies were analyzed. In the 13 long-term studies that included 658 participants, the exercise intervention time ranged from 2 to 16 weeks (Table 1 ). Three studies focused on patients with T2D: one on patients with cardiovascular artery disease, two on healthy people, six on healthy overweight and obese people, and one on patients with metabolic syndrome (MetS). In terms of exercise intervention protocols, the studies included one study using strength training, two using combined aerobic and strength training, one using low-intensity walking, three using high-intensity interval training (HIIT), five Table 1 Qualitative analysis of the included Long term studies Reference Subject Study design Exercise Protocol Frequency Training duration Time of training Diet Results Carrillo et al.2024 27 18 T2D subjects (9 M) 61 ± 2yr BMI:30.6 ± 0.7kg/m 2 Randomized crossover exercise(2 weeks wash-out) 30 min walking at 70% max-HR 3 sessions/week 6 weeks Morning:7:00–10:00 Afternoon:16:00–19:00 Maintain normal eating habits Morning moderate intensity exercise acutely reduces glycaemia in people with type 2 Diabetes also being prescribed metformin. Palomo et al.2023 28 139 MetS subjects (90 M) 57 yr BMI:30.6 kg/m 2 Randomized controlled trial HIIT: 4 × 4 min intervals at 90% of HRmax 3 sessions/week 16 weeks Morning:8:00–9:00 Afternoon:16:00–17:00 Maintain normal eating habits Eat an hour before exercise High-intensity aerobic exercise training in the morning is more efficient at reducing cardiometabolic risk factors Brooker et al.2023 29 65 obesity subjects AMEx: 41 ± 12 year BMI:31 ± 4.3kg/m 2 PMEx༚38 ± 11 year BMI:32 ± 5.9kg/m 2 Three-armed randomized controlled trial 250 min per week of self-paced aerobic exercise 250min/week 12 weeks Morning:6:00–9:00 Afternoon:16:00–19:00 Maintain normal eating habit Afternoon group had a more significant weight loss than the morning group. Creasy et al. 2022 30 33 obesity subjects (10 M) AM: 40.8 ± 8.4 year BMI༚30.0 ± 3.9kg/m 2 PM༚36.4 ± 10.8yrBMI༚30.6 ± 4.7kg/m 2 Randomized controlled trial From 70–80% heart rate maximum and 750–2000 kcal/week supervised aerobic exercise 1 on-own, 3 supervised sessions/week 15 weeks Morning: 06:00–10:00 Afternoon: 15:00–19:00 Eat freely throughout the study Afternoon exercise loses more weight Teo et al.2021 31 40 obesity subjects (17 M) 51 ± 13yr BMI:30.9 ± 4.2 kg/m 2 Randomized controlled trial 30 minutes of aerobic exercise at 70% VO2peak and 30 minutes of resistance exercise 3 sessions/week 12 weeks Morning: 08:00–10:00 Afternoon 17:00–19:00 Eatl at least 1h before training Maintain normal eating habit In the absence of dietary manipulation, the effect of diurnal exercise timing on body composition appear trivial. Teo et al.2020 32 40 obesity subjects (17 M) 51 ± 13yr BMI:30.9 ± 4.2 kg/m 2 Randomized controlled triaL Moderate intensity (30 minutes of treadmill walking at 60–70% of VO2 peak) 3 sessions/week 12 weeks Morning :08:00–10:00 Afternoon :17:00–19:00 Maintain usual eating habits PmEX group conveyed no statistical improvement in glycemic,insulin sensitivity versus amEX group Brooker et al.2019 33 20 inactive, overweight subjects (6 M) 39 ± 13yr BMI:30.9 ± 4.2 kg/m 2 Three-armed, randomized controlled trial Self-paced moderate-vigorous walking or running on a treadmill to achieve a weekly total of 250 min 250min/week 12 weeks Morning:06:00–09:00 Afternoon: 16:00–19:00 Maintain normal eating habit Afternoon exercise improves body composition and lowers blood glucose Alizadeh et al.2017 34 48 overweight females AMEx: 33.56 ± 5.98yr BMI:27.3 ± 1.52kg/m 2 PMEx: 33.89 ± 6.58yr BMI:27.6 ± 1.42kg/m 2 Randomized controlled trial Aerobic exercise at a target heart rate on the ventilatory threshold for 30mins 3 sessions/week 6 weeks Morning: 08:00–10:00 Afternoon:14:00–16:00 Maintain normal eating habit Aerobic exercise in the morning could be considered a more effective programme than evening exercise on weight loss Savikj et al.2022 35 8 T2D subjects (8 M) 62 ± 8yr BMI:27.4 ± 1.9kg/m 2 Randomized crossover trial (2 weeks wash-out) Six one-minute pulses at individual maximal load and 75 rpm 3 sessions/week 2 weeks Morning: 08:00 Afternoon:16:45 Maintain normal eating habits Training's impact on metabolic parameters was not observed Lian et al.2014 36 178 subjects with CAD (133 M) Morning group:64 ± 9 year BMI:24.97 ± 2.71kg/m 2 Evening group:62 ± 10 year BMI:24.59 ± 2.66kg/m 2 Randomized controlled trial Walk at the speed of 2.5 miles/h for 30 min/day 5 days/week 12 weeks Not stated All participants were given similar dietary advice by dietitians Evening walking group gained more benefits in lipids. Arciero et al.2022 18 27 exercise-trained women: 42 ± 8yr BMI:24 ± 3 kg/m 2 20 exercise-trained men: 45 ± 8yr BMI:25.5 ± 3 kg/m 2 Randomized controlled trial RISE training for 1h 4 sessions/week 12 weeks Morning: 06:00–08:00 Afternoon:18:30 − 20:30 Maintain normal eating habits Men: TC,HDL declined significantly in PM in Women: Both AM and PM groups reduced total body fat, increased fat-free mass Krčmárová et al.2018 37 31 women 66 ± 4 yr Randomized controlled trial Progressive strength-training for 8 exercises, with 3 sets for each exercise, and 10–12 repetitions per set. 2 sessions/week 12 weeks Morning: 07:30 Afternoon: 18:00 Follow a diet plan,no significant change in energy intake Similar circadian effects of exercise on muscle strength and blood glucose Savikj et al.2019 35 11 T2D subjects (11 M) 60 ± 2 year BMI: 27.5 ± 0.6 kg/m 2 Randomized crossover trial (2 weeks wash-out) HIIT: on cycle-ergometer 6 × 1 min at maximal load + 1 min low load 3 sessions/week 2 weeks Morning: 08:00 Afternoon : 16:00 Standardized snack was offered 30 minutes after the afternoon training,no significant change in energy intake Afternoon HIIT reduced glucose concentration Table 2 Qualitative analysis of the included Acute studies Reference Subjects Study design Exercise protocol Training duration Time of training Diet Results Kim et al.2022 38 12 healthy young men 21.8 ± 0.2yr BMI: 21.3 kg/m² Randomized crossover trial 60 min on a treadmill at 60% VO 2 max for 3 sessions 1 week Morning: 09:00–11:00 Afternoon : 16:00–18:00 Maintain normal eating habits Endurance exercise in the late afternoon was more effective in improving blood sugar and lipid levels over a 24-hour period Moholdt et al.2021 39 24 obesity participants (24 M) 35-36yr BMI:31.2 ± 2.3 kg/m 2 Three-armed randomized controlled trial DAY 1,3,5: HIT, 10 × 1-min work-bouts and 1-min low-intensity cycling DAY 2,4: 40、60 min of moderate-intensity continuous cycling. 5 days Morning: 06:30 Afternoon: 18:30 11days of high-fat diet before and during exercise Fasting blood glucose, insulin, cholesterol, triacylglycerol, and LDL-cholesterol concentrations decrease in afternoon exercise Tanaka et al.2021 40 11 healthy young men 22-30yr Randomized crossover trial 60% of ̇VO2max for 1 h using a cycle ergometer for 4 sessions 1 day Morning: 07:00 Afternoon ༚16:00 Experimental meals Glucose levels during exercise were only decreased in the afternoon exercise trial Munan et al.2020 41 14 T2D participants (8 M) 65 ± 9.0yr BMI: 27.2 ± 3.5 kg/m² Randomized crossover trial 50 min of walking at a speed of 5.0 km/h for 4 sessions 12days Morning: exercise ending 20 min before breakfast Afternoon༚starting 3 or 4 hours after lunch and ending 20 min before dinner Standardized meals are provided on the exercise day and the following day to ensure energy balance. The decrease in blood glucose was more pronounced in the afternoon exercise Toghi-Eshghi et al.2019 42 12 T1D participants (3 M) 31.3 year BMI: 26.6 kg/m² Randomized crossover trial 40 min of RE at 8RM load for 2 sessions ≥ 48 hours between 2 tests Morning: 07:00 Afternoon ༚17:00 Morning training: fasting state before the afternoon training༚standardized snack at 16:00 Blood glucose decreased after the afternoon exercise BMI, body mass index; T2D, type 2 diabetes; T1D, type 1 diabetes; yr, years using aerobic training, and one using a multi-sport training model. Finally, three studies used a crossover design with 2-week washout periods, and 10 used a randomized controlled trial (RCT) design. In the five acute studies shown in Table 2 , which included 73 participants, the exercise intervention time ranged from 40 to 60 min, and exercise period varied from 1 to 12 days. Among selected studies, two were conducted on healthy individuals, one on participants with obesity, one on patients with T2D, and one on type 1 diabetes (T1D). In terms of exercise intervention protocols, one study implemented a low-intensity walking program, one used HIIT, three employed aerobic training, and one a resistance training program. Regarding the study design, four studies adopted a crossover design, and one utilized an RCT scheme. Notably, Aricero et al. 18 reported data from male and female participants, whereas Teo et al. 32 reported data from patients with T2D and healthy individuals. In terms of diet, Carrillo et al. 27 enrolled 18 patients with T2D who walked at 70% of their maximum heart rate for 3 to 6 min in the morning and afternoon, maintaining their daily eating habits. Caloric intake for breakfast, lunch, and dinner did not differ significantly during the trial period. Brooker et al. 29 conducted a study on 65 patients with obesity who maintained a controlled diet. After 12 weeks, both the AMEx and PMEx groups showed a reduction in total energy intake during the intervention period. A significant difference was observed in these groups compared with the control group (AMEx − 3974 kJ, p < 0.001; PMEx − 3165 kJ, p = 0.001). Protein intake in the AMEx group was significantly decreased in the middle and later stages (p < 0.05), whereas total fat intake in the PMEx group significantly decreased in the later stages (p < 0.05). Similarly, Teo et al. 31 included 40 patients with obesity and observed significant reductions in total energy intake in both groups; however, Alizadeh et al. 34 noted a significant reduction in total energy intake over 6 weeks (p = 0.06) in the MT group among 48 women with obesity. In contrast, the AT group did not experience a significant change in total energy intake. 3.2 Body composition 3.2.1 Body weight Six studies across seven different populations assessed body weight. No differences were observed between AT and MT in reducing body weight (MD -0.38, 95% CI -0.96 to 0.09, I 2 = 0%, p = 0.19). The Egger test result was not significant (p = 0.907) (Supplementary Fig. 1). Leave-one-out analysis showed that none of the studies influenced this effect. 3.2.2 BMI BMI was evaluated in four studies involving four different populations. No differences were noted between AT and MT in reducing BMI (MD -0.2, 95% CI -0.59 to 0.19, I 2 = 67%, p = 0.32). Publication bias was not detected (p = 0.613) (Supplementary Fig. 2). Leave-one-out analysis revealed that any study did not influence the overall outcome. 3.2.3 Fat mass Seven studies involving eight populations evaluated fat mass. The results showed no differences between AT and MT in reducing fat mass (MD 0.31, 95% CI -0.28 to 0.90, I 2 = 0%, p = 0.3). The Egger test result was not significant (p = 0.871) (Supplementary Fig. 3). Sensitivity analysis showed consistent results across studies. 3.2.4 Fat-free mass The fat-free mass was evaluated in six studies involving seven different populations. No differences were observed between AT and MT in reducing fat-free mass (MD 0.14, 95% CI -0.35 to 0.64, I 2 = 0%, p = 0.57). The Egger test indicated no publication bias (p = 0.973) (Supplementary Fig. 4). Leave-one-out analysis confirmed that individual studies did not affect the outcome. 3.2.5 Body fat Five studies across six different populations investigated body fat. MT reduced body fat more effectively than AT (MD -0.39, 95% CI -0.66 to -0.13, I 2 = 0%, p = 0.004). No publication bias was observed (p = 0.973) (Supplementary Fig. 5). However, leave-one-out analysis showed that removing the study by Alizadeh et al. 34 nullified the significant advantage of MT (MD 0.27, 95% CI -0.39 to 0.94, I 2 = 0%, p = 0.42). 3.2.6 Waist circumference Waist circumference was evaluated in four studies involving four different populations. MT was more effective than AT at reducing waist circumference (MD -0.53, 95% CI -1.06 to -0.00, I 2 = 31%, p = 0.05). Subgroup analysis indicated that aerobic exercise was more beneficial than mixed resistance-aerobic routines. The Egger showed no publication bias (p = 0.914) (Supplementary Fig. 6). However, the effect was no longer significant when the study by Alizadeh et al. 34 was excluded (MD 0.67, 95% CI -0.63 to 1.96, I 2 = 0%, p = 0.31). 3.3 Glycemic control 3.3.1 FBG Eight studies involving 10 populations analyzed FBG, and AT reduced FBG more effectively than MT (MD 0.13, 95% CI -0.01 to 0.24, I 2 = 0%, p = 0.03). Subgroup analysis found no significant difference in the duration of exercise required to lower blood sugar levels between patients with and without diabetes. The Egger test result was significant (p = 0.034) (Supplementary Fig. 7). Leave-one-out analysis showed that the results were no longer significantly biased in favor of AT for reducing blood glucose after excluding the studies by Brooker et al. 33 and Savikj et al. 43 . In the acute studies, three studies involving three populations evaluated FBG levels; no differences were observed between AT and MT in terms of reducing glucose levels (MD -0.72, 95% CI -2.12 to 0.67, I 2 = 98%, p = 0.31). The Egger test result was significant (p = 0.334) (Supplementary Fig. 8). Leave-one-out analysis showed stable outcomes across studies. Blood glucose differences before and after exercise were also evaluated in three studies with three different populations. AT was more effective than MT at reducing FBG (MD 0.53, 95% CI 0.32 to 0.73, I 2 = 21%, p < 0.01). Publication bias was marginal (p = 0.075) (Supplementary Fig. 9). However, when excluding the study by Tanaka et al. 40 , the results were no longer significantly biased in favor of AT to reduce the blood glucose difference before and after exercise (MD 0.48, 95% CI -0.36 to 1.33, I 2 = 60%, p = 0.26). 3.3.2 HbA1c HbA1c was evaluated in four studies involving distinct populations, and MT was more effective than AT at reducing HbA1c (MD -0.11, 95% CI -0.19 to -0.03, I 2 = 0%, p = 0.009) (Supplementary Fig. 10). The Egger test revealed no publication bias (p = 0.46). Sensitivity analysis indicated that when excluding the study by Teo et al. 32 , the results were no longer significantly biased in favor of MT in reducing HbA1c. 3.3.3 Fasting insulin Fasting insulin was described in five studies with seven different populations. There were no differences between AT and MT in reducing insulin levels (MD 0.09, 95% CI -0.37 to 0.54, I 2 = 0%, p = 0.71). The Egger test was not significant (p = 0.056) (Supplementary Fig. 11). The leave-one-out analysis showed that none of the studies was influencing the effect. 3.3.4 HOMA-IR HOMA-IR was described in three studies with four different populations. There were no differences between AT and MT in reducing HOMA-IR levels (MD 0.02, 95% CI -0.21 to -0.16, I 2 = 0%, p = 0.8). The Egger test was not significant (p = 0.284) (Supplementary Fig. 12). The leave-one-out analysis showed that none of the studies was influencing the effect. 3.4 Blood Lipids 3.4.1 TG Analysis of TG across nine independent population studies demonstrated AT tended to be more effective than MT at reducing TG (MD 0.1, 95% CI 0.02 to 0.18, I 2 = 41%, p = 0.02). Publication bias assessment through Egger's test yielded non-significant results (p = 0.188) (Supplementary Fig. 13). The leave-one-out analysis showed when excluding studies of Krčmárová et al. 37 or Lian et al. 36 , the model the effect size rose to almost a trend towards a better effect for AT. 3.4.2 TC TC was evaluated in seven studies with eight different populations. There were no differences between AT and MT to reduce TC levels (MD 0.02, 95% CI -0.08 to 0.05, I 2 = 36%, p = 0.61). The Egger test was not significant (p = 0.517) (Supplementary Fig. 14). The leave-one-out analysis showed that none of the studies was influencing the effect. 3.4.3 HDL HDL was evaluated in eight studies with nine different populations. We found that AT tended to be more effective than MT at reducing HDL (MD 0.04, 95% CI -0.00 to 0.09, I 2 = 11%, p = 0.06). The Egger test was not significant (p = 0.864) (Supplementary Fig. 15). The leave-one-out analysis showed that the study by Brooker et al. 33 was influencing the results. When leaving this study out of the analysis, the effects of the model showed that afternoon exercise was more efficient in lowering HDL levels (MD 0.05, 95% CI 0.00 to 0.10, I 2 = 1%, p = 0.03). The study by Krčmárová et al. 37 was influencing the results. When leaving this study out of the analysis, the effects of the model showed that afternoon exercise was more efficient in lowering HDL levels (MD 0.05, 95% CI 0.00 to 0.10, I 2 = 0%, p = 0.04). Furthermore, the study by Lian et al. 36 influenced the results. When leaving this study out of the analysis, the effects of the model showed that afternoon exercise was more efficient in lowering HDL levels (MD 0.06, 95% CI 0.01 to 0.11, I 2 = 3%, p = 0.02). 3.4.4 LDL LDL was evaluated in eight studies with nine different populations. No differences between AT and MT in reducing LDL levels (MD -0.06, 95% CI -0.13 to 0.01, I 2 = 19%, p = 0.09) were observed. The Egger test was not significant (p = 0.300) (Supplementary Fig. 16). The leave-one-out analysis showed that the study by Savikj et al. 38 was influencing the results. When leaving this study out of the analysis, the effects of the model were biased to show that morning exercise was more efficient in lowering LDL levels (MD -0.08, 95% CI -0.15 to 0.00, I 2 = 15%, p = 0.05). 4 Discussion This meta-analysis highlights the distinct effects of MT and AT on body composition, glycemic control, and lipid metabolism. AT showed better outcomes in reducing TG and FBG levels, whereas MT was more effective in reducing body fat, waist circumference, and HbA1c. These results highlight the role of exercise timing and circadian rhythms in metabolic health. Exercise can reduce obesity, and this study showed that MT had a greater effect on body fat and waist circumference than AT, consistent with previous studies. For example, one study found that those who exercised moderately to vigorously between 7 and 9 AM had a lower BMI than those who exercised during the middle of the day or at night 44 . A cross-sectional analysis of the health of 7,157 women suggested that those who exercised less in the morning may have a higher risk of obesity 45 . Similarly, consistent MT improved exercise adherence and weight management in overweight or obese individuals 46 . The analysis of glycemic markers revealed that mid-to-long-term AT more effectively improved FBG, whereas MT showed greater benefits for reducing HbA1c. AT may acutely improve FBG levels by aligning with circadian insulin sensitivity peaks, whereas MT enhances long-term HbA1c levels through sustained metabolic adaptations, such as improved insulin sensitivity and fat oxidation. Additionally, the HbA1c analysis may have included more people with T2D, whereas the FBG analysis may have covered a broader population, including healthy people and people with diabetes. Similarly, Mancilla et al. investigated 32 adult males at risk for or diagnosed with T2D and found that AT improved FBG levels better than MT 47 . However, a recent randomized controlled trial showed that moderate exercise in the morning significantly reduced FBG in patients with T2D who took metformin and that the glucose area under the curve values was significantly reduced only in the case of MT and taking metformin before breakfast 27 . These results suggest an association between MT and the time of taking metformin to affect blood glucose levels. In the acute studies analyzed, blood glucose levels consistently showed improvement after AT. AT to improve TG was an important finding in this study and is consistent with the results of a recent meta-analysis 17 . However, a cross-sectional study of 51 older adults showed that MT tended to lower LDL and may be more beneficial to lowering blood lipids than AT 48 . This discrepancy may be because the average age of the participants included in this study was 71.8 years, and the effect of exercise on blood lipid improvement differed between age groups. The possible mechanisms underlying these results may include MT-induced stimulation of the sympathetic nervous system, leading to increased catecholamine secretion. These hormones enhance lipolysis and elevate energy expenditure by activating β-adrenergic receptors in adipose tissue and skeletal muscle. MT has also been associated with a prolonged increase in resting metabolic rate, reflecting the energy required for basic physiological functions at rest. Exercise promotes the formation of new mitochondria, thereby enhancing cellular energy production and utilization 49 . Additionally, human skeletal muscular strength and mitochondrial function typically peak in during AT, which may more effectively regulate blood sugar glucose levels by enhancing glucose uptake and utilization by muscle tissue 43 . Although this study provides a systematic review and meta-analysis of the effects of exercise duration on metabolic health, some limitations should be addressed. First, variation in baseline health and age across study participants may have affected the consistency of the results. Second, the duration of the included medium- and long-term studies was limited, and acute studies were even fewer, which may have affected the robustness of the results. Third, the sensitivity analyses may be biased owing to the insufficient number of studies included. 5 Conclusion MT and AT yield distinct metabolic benefits. Specifically, MT was more effective in reducing body fat percentage and waist circumference and improving HbA1c levels, whereas AT showed superior results in regulating FBG and lowering TG levels. The differential effects of MT and AT observed in this study have practical implications for personalized exercise interventions. AT may offer more pronounced benefits for individuals who aim to improve glycemic control, especially those with insulin resistance or elevated FBG. In contrast, MT may be used by those focusing on fat loss and weight management. Incorporating exercise timing into clinical guidelines could enhance the effectiveness of lifestyle interventions for metabolic disorders. However, future research should explore the effects of exercise on metabolic health at different times before or after meals, as well as the immediate and long-term effects of exercise of different intensities, durations, and frequencies in different populations. In addition, future studies should consider more demographic factors, such as sex, age, and health status, to better understand the influence of exercise timing on metabolic health. Abbreviations 1. T2D: Type 2 Diabetes 2. HTN: Hypertension 3. MetS: Metabolic Syndrome 4. MT: Morning Training 5. AT: Afternoon Training 6. TG: Triglycerides 7. PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses 8. PROSPERO: International Prospective Register of Systematic Reviews 9. WOS: Web of Science 10. RCT: Randomized Controlled Trial 11. BMI: Body Mass Index 12. FBG: Fasting Blood Glucose 13. HbA1c: Hemoglobin A1c 14. HOMA-IR: Homeostatic Model Assessment for Insulin Resistance 15. TC: Total Cholesterol 16. HDL: High-Density Lipoproteins 17. LDL: Low-Density Lipoproteins 18. SD: Standard Deviation 19. MD: Mean Deviation 20. CI: Confidence Interval 21. HIIT: High-Intensity Interval Training 22. VO2: Volume of Oxygen 23. T1D: Type 1 Diabetes 24. CAD: Coronary Artery Disease Declarations 1. Ethics approval and consent to participate Consent for publication Not Applicable 2. Consent for publication All authors have provided their consent for publication. 3. Availability of data and material Not Applicable 4.Competing interests This article has no financial or non-financial competing interests. 5.Funding This work was supported by the National Natural Science Foundation of China [Grant Number 32400953]. 6. Authors' contributions JW: Conceptualization, Investigation, Data curation, Writing, original draft. SC: Methodology, Formal analysis, Validation, Writing, review & editing. ZZ: Software, Visualization, Investigation, Data curation. BY: Resources, Writing, review & editing, Supervision. XZ: Supervision, Project administration, Funding acquisition, Writing, review & editing (Corresponding author). 7. Acknowledgements Thank to all the authors whose work contributed to this meta-analysis. Their researches and willingness to share data were essential for our findings and advancing knowledge in this field. References Chaves, S. F. N., Silva Araújo, D. P. da, Guilherme, L. Q. & Agostinho, P. A. G. Diagnosis, physiological mechanisms, risk factors, treatment and prevention of obesity: A brief commentary. Obes. Med. 52 , 100572 (2024). Sun, X. et al. Expert Consensus and Call on Actions for Weight Management in China: Advancing Healthy China Initiative Through Strategic Actions. China CDC Wkly. 6 , 1347–1353 (2024). de Mello, A. H., Prá, M., Cardoso, L. C., de Bona Schraiber, R. & Rezin, G. T. Incretin-based therapies for obesity treatment. Metabolism. 64 , 967–981 (2015). Peri, K. & Eisenberg, M. Review on the update in obesity management: epidemiology. BMJ Public Health 2 , (2024). Caballero, B. Humans against Obesity: Who Will Win? Adv. Nutr. Bethesda Md 10 , S4–S9 (2019). Chew, N. W. S. et al. The global burden of metabolic disease: Data from 2000 to 2019. Cell Metab. 35 , 414-428.e3 (2023). Pedersen, B. K. & Saltin, B. Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases. Scand. J. Med. Sci. Sports 25 Suppl 3 , 1–72 (2015). Gabriel, B. M. & Zierath, J. R. The Limits of Exercise Physiology: From Performance to Health. Cell Metab. 25 , 1000–1011 (2017). Schroeder, A. M. et al. Voluntary scheduled exercise alters diurnal rhythms of behaviour, physiology and gene expression in wild-type and vasoactive intestinal peptide-deficient mice. J. Physiol. 590 , 6213–6226 (2012). Moderate intensity walking exercises reduce the body mass index and vascular inflammatory factors in postmenopausal women with obesity: a randomized controlled trial | Scientific Reports. https://www.nature.com/articles/s41598-023-47403-2. Eglseer, D. et al. Nutrition and Exercise Interventions to Improve Body Composition for Persons with Overweight or Obesity Near Retirement Age: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials. Adv. Nutr. Bethesda Md 14 , 516–538 (2023). Motahari-Tabari, N., Ahmad Shirvani, M., Shirzad-E-Ahoodashty, M., Yousefi-Abdolmaleki, E. & Teimourzadeh, M. The effect of 8 weeks aerobic exercise on insulin resistance in type 2 diabetes: a randomized clinical trial. Glob. J. Health Sci. 7 , 115–121 (2014). Sanchis-Gomar, F. et al. The Acquisition of Cardiovascular Adaptation to Aerobic Exercise: When Does It Begin and How Does It Evolve Depending on Intrinsic and Extrinsic Factors? Can. J. Cardiol. S0828-282X(24)01320–5 (2024) doi:10.1016/j.cjca.2024.12.023. Rynders, C. A. & Broussard, J. L. Running the clock: new insights into exercise and circadian rhythms for optimal metabolic health. J. Physiol. 602 , 6367–6371 (2024). Dighriri, A. et al. The impact of the time of day on metabolic responses to exercise in adults: A systematic and meta-analysis review. Chronobiol. Int. 41 , 1377–1388 (2024). Sevilla-Lorente, R., Carneiro-Barrera, A., Molina-Garcia, P., Ruiz, J. R. & Amaro-Gahete, F. J. Time of the day of exercise impact on cardiovascular disease risk factors in adults: a systematic review and meta-analysis. J. Sci. Med. Sport 26 , 169–179 (2023). Galan-Lopez, P. & Casuso, R. A. Metabolic Adaptations to Morning Versus Afternoon Training: A Systematic Review and Meta-analysis. Sports Med. 53 , 1951–1961 (2023). Arciero, P. J. et al. Morning Exercise Reduces Abdominal Fat and Blood Pressure in Women; Evening Exercise Increases Muscular Performance in Women and Lowers Blood Pressure in Men. Front. Physiol. 13 , 893783 (2022). Thomas, G. A. et al. Obesity, growth hormone and exercise. Sports Med. Auckl. NZ 43 , 839–849 (2013). Page, M. J. et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Rev. Espanola Cardiol. Engl. Ed 74 , 790–799 (2021). Wan, X., Wang, W., Liu, J. & Tong, T. Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range. BMC Med. Res. Methodol. 14 , 135 (2014). Luo, D., Wan, X., Liu, J. & Tong, T. Optimally estimating the sample mean from the sample size, median, mid-range, and/or mid-quartile range. Stat. Methods Med. Res. 27 , 1785–1805 (2018). Mason, S. A., Keske, M. A. & Wadley, G. D. Effects of Vitamin C Supplementation on Glycemic Control and Cardiovascular Risk Factors in People With Type 2 Diabetes: A GRADE-Assessed Systematic Review and Meta-analysis of Randomized Controlled Trials. Diabetes Care 44 , 618–630 (2021). Cumpston, M. et al. Updated guidance for trusted systematic reviews: a new edition of the Cochrane Handbook for Systematic Reviews of Interventions. Cochrane Database Syst. Rev. 10 , ED000142 (2019). Sterne, J. A. C. et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ 366 , l4898 (2019). Pérez-Rodríguez, M., Huertas, J. R., Villalba, J. M. & Casuso, R. A. Mitochondrial adaptations to calorie restriction and bariatric surgery in human skeletal muscle: a systematic review with meta-analysis. Metabolism. 138 , 155336 (2023). Carrillo, B. J. P. et al. Morning exercise and pre-breakfast metformin interact to reduce glycaemia in people with type 2 diabetes: a randomized crossover trial. J. Physiol. (2024) doi:10.1113/JP285722. Morales-Palomo, F. et al. Efficacy of morning versus afternoon aerobic exercise training on reducing metabolic syndrome components: A randomized controlled trial. J. Physiol. n/a ,. Brooker, P. G., Gomersall, S. R., King, N. A. & Leveritt, M. D. The efficacy of morning versus evening exercise for weight loss: A randomized controlled trial. Obes. Silver Spring Md 31 , 83–95 (2023). Creasy, S. A. et al. Effect of Morning and Evening Exercise on Energy Balance: A Pilot Study. Nutrients 14 , 816 (2022). Teo, S. Y. M. et al. Effects of diurnal exercise timing on appetite, energy intake and body composition: A parallel randomized trial. Appetite 167 , 105600 (2021). Teo, S. Y. M., Kanaley, J. A., Guelfi, K. J., Marston, K. J. & Fairchild, T. J. The Effect of Exercise Timing on Glycemic Control: A Randomized Clinical Trial. Med. Sci. Sports Exerc. 52 , 323–334 (2020). Brooker, P. G., Gomersall, S. R., King, N. A. & Leveritt, M. D. The feasibility and acceptability of morning versus evening exercise for overweight and obese adults: A randomized controlled trial. Contemp. Clin. Trials Commun. 14 , 100320 (2019). Alizadeh, Z., Younespour, S., Rajabian Tabesh, M. & Haghravan, S. Comparison between the effect of 6 weeks of morning or evening aerobic exercise on appetite and anthropometric indices: a randomized controlled trial. Clin. Obes. 7 , 157–165 (2017). Savikj, M. et al. Exercise timing influences multi-tissue metabolome and skeletal muscle proteome profiles in type 2 diabetic patients - A randomized crossover trial. Metabolism. 135 , 155268 (2022). Lian, X.-Q. et al. The influence of regular walking at different times of day on blood lipids and inflammatory markers in sedentary patients with coronary artery disease. Prev. Med. 58 , 64–69 (2014). Krčmárová, B. et al. The effects of 12-week progressive strength training on strength, functional capacity, metabolic biomarkers, and serum hormone concentrations in healthy older women: morning versus evening training. Chronobiol. Int. 35 , 1490–1502 (2018). Kim, H.-K. et al. Late-afternoon endurance exercise is more effective than morning endurance exercise at improving 24-h glucose and blood lipid levels. Front. Endocrinol. 13 , 957239 (2022). Moholdt, T. et al. The effect of morning vs evening exercise training on glycaemic control and serum metabolites in overweight/obese men: a randomised trial. Diabetologia 64 , 2061–2076 (2021). Tanaka, Y. et al. Effect of a single bout of morning or afternoon exercise on glucose fluctuation in young healthy men. Physiol. Rep. 9 , e14784 (2021). Munan, M. et al. Does Exercise Timing Affect 24-Hour Glucose Concentrations in Adults With Type 2 Diabetes? A Follow Up to the Exercise-Physical Activity and Diabetes Glucose Monitoring Study. Can. J. Diabetes 44 , 711-718.e1 (2020). Toghi-Eshghi, S. R. & Yardley, J. E. Morning (Fasting) vs Afternoon Resistance Exercise in Individuals With Type 1 Diabetes: A Randomized Crossover Study. J. Clin. Endocrinol. Metab. 104 , 5217–5224 (2019). Savikj, M. et al. Afternoon exercise is more efficacious than morning exercise at improving blood glucose levels in individuals with type 2 diabetes: a randomised crossover trial. Diabetologia 62 , 233–237 (2019). Ma, T., Bennett, T., Lee, C.-D. & Wicklow, M. The diurnal pattern of moderate-to-vigorous physical activity and obesity: a cross-sectional analysis. Obesity 31 , 2638–2647 (2023). Chomistek, A. K., Shiroma, E. J. & Lee, I.-M. The Relationship Between Time of Day of Physical Activity and Obesity in Older Women. J. Phys. Act. Health 13 , 416–418 (2016). Schumacher, L. M., Thomas, J. G., Raynor, H. A., Rhodes, R. E. & Bond, D. S. Consistent Morning Exercise May Be Beneficial for Individuals With Obesity. Exerc. Sport Sci. Rev. 48 , 201–208 (2020). Mancilla, R. et al. Exercise training elicits superior metabolic effects when performed in the afternoon compared to morning in metabolically compromised humans. Physiol. Rep. 8 , e14669 (2021). Kim, H.-K. et al. Morning physical activity may be more beneficial for blood lipids than afternoon physical activity in older adults: a cross-sectional study. Eur. J. Appl. Physiol. 124 , 3253–3263 (2024). Mueller, P. J. Exercise training and sympathetic nervous system activity: evidence for physical activity dependent neural plasticity. Clin. Exp. Pharmacol. Physiol. 34 , 377–384 (2007). Supplementary Files Supplementaryfiles.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 07 Sep, 2025 Reviewers invited by journal 26 Aug, 2025 Editor assigned by journal 27 Jul, 2025 First submitted to journal 25 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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composition\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-7182337/v1/b92ce594a591a117ab923be3.png"},{"id":90542555,"identity":"59bae04e-53fc-462d-a5aa-4dd0c312384c","added_by":"auto","created_at":"2025-09-04 00:04:30","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":333259,"visible":true,"origin":"","legend":"\u003cp\u003eLong term effects of exercise on glycometabolism\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-7182337/v1/5be2809aa0a74fbfa36ae5a5.png"},{"id":90541422,"identity":"fa6f1098-11bb-4621-99a0-fbf2433ea3f4","added_by":"auto","created_at":"2025-09-03 23:56:30","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":194726,"visible":true,"origin":"","legend":"\u003cp\u003eLong term effects of exercise on blood lipids\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-7182337/v1/4b4dba5a0ca9b06a9eab8e95.png"},{"id":90541436,"identity":"f2c13ca1-e1e0-4cff-8124-88d8eb0aa229","added_by":"auto","created_at":"2025-09-03 23:56:30","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":234444,"visible":true,"origin":"","legend":"\u003cp\u003eAcute effects of exercise on glycometabolism\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-7182337/v1/33958bde4af756b4d7c1e676.png"},{"id":90543414,"identity":"9f74240d-23e2-4d71-8c15-d705aa8942d1","added_by":"auto","created_at":"2025-09-04 00:12:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2244252,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7182337/v1/47c4c3a1-0bdf-4f7a-b24a-c5d529314b67.pdf"},{"id":90542552,"identity":"fe6198e7-392d-43c1-95a6-12cbc43c2dca","added_by":"auto","created_at":"2025-09-04 00:04:30","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":728241,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementaryfiles.docx","url":"https://assets-eu.researchsquare.com/files/rs-7182337/v1/0b34af7a67c13b0b3c1d5480.docx"}],"financialInterests":"","formattedTitle":"\u003cp\u003eInfluence of Morning and Afternoon Exercise on Body Composition and Metabolic Health\u003c/p\u003e","fulltext":[{"header":"Key points","content":"\u003cp\u003eBoth morning and afternoon exercise offer benefits for metabolic health, but they have different effects. Morning training is more effective at reducing body fat, waist circumference, and HbA1c levels, which are important for long-term blood sugar control. In contrast, afternoon training is better at lowering fasting blood glucose and triglycerides, which can help with short-term blood sugar management and reducing fat in the blood.\u003c/p\u003e"},{"header":"1 Introduction","content":"\u003cp\u003eWith the worldwide increasing incidence of obesity and metabolic diseases such as type 2 diabetes (T2D) and cardiovascular disorders, identifying effective methods for managing weight and improving metabolic health has become essential\u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. The Global Burden of Disease Group reported in 2017 that \u0026ldquo;since 1980, the prevalence of obesity has doubled in more than 70 countries and has continuously increased in most other countries\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u0026rdquo; Over the past 20 years, the prevalence of metabolic diseases such as T2D mellitus (T2DM) has increased by more than 1.5%, hypertension (HTN) by 0.2%, and non-alcoholic fatty liver disease by 0.83% annually\u003csup\u003e6\u003c/sup\u003e. Exercise, as a non-pharmacological strategy\u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e, has been widely acknowledged for its beneficial effects in enhancing body composition\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e, glucose metabolism, and lipid profiles\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Recently, the effect of exercise timing on metabolic health has been investigated, and the concept of timed exercise was proposed\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eExercise timing may differentially influence metabolic responses. However, these findings remain inconsistent. A recent meta-analysis showed that exercise timing did not affect the acute cardiometabolic response to exercise\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. In contrast, another meta-analysis indicated no significant difference in metabolic adaptation between morning training (MT) and afternoon training (AT) but demonstrated the superior efficacy of AT in reducing circulating triglyceride (TG) levels\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. MT is more effective than AT in reducing abdominal fat in healthy women. However, in men, AT increased lipid oxidation compared to MT\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Furthermore, exercise-induced increases in blood adrenaline, growth hormone, and interleukin-6 levels promote lipolysis, suggesting that AT is more effective in promoting lipolysis than MT\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. However, the results of these studies are inconsistent and contradictory, possibly because of differences in the study design, sample size, exercise protocol, and measurement metrics, leaving a substantial gap in the understanding of the optimal exercise timing for metabolic benefits.\u003c/p\u003e\u003cp\u003eTherefore, a more comprehensive approach, such as systematic review and meta-analysis are necessary to obtain a better understanding of the effects of timed exercise on body composition, glucose metabolism, and lipid metabolism. This meta-analysis was expanded by including acute studies and additional body composition metrics to provide a deeper understanding of the effects of exercise timing on metabolic health. By synthesizing existing evidence, this study aimed to clarify temporal patterns of exercise and their influence on metabolic health, offering novel insights for individualized exercise interventions.\u003c/p\u003e"},{"header":"2 Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1 Search strategy and data selection\u003c/h2\u003e\n \u003cp\u003eThis review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD420250619379). A literature search was conducted using electronic databases, such as PubMed, Embase, and Web of Science (WOS). The search ended in March 2025. Only articles published in English were included. The following search strategy was used: (\u0026ldquo;exercise\u0026rdquo; or \u0026ldquo;training\u0026rdquo; or \u0026ldquo;sport\u0026rdquo; or \u0026ldquo;physical activity\u0026rdquo; or \u0026ldquo;athletics\u0026rdquo; or \u0026ldquo;workout\u0026rdquo; or \u0026ldquo;fitness\u0026rdquo; or \u0026ldquo;play\u0026rdquo; or \u0026ldquo;movement\u0026rdquo;) and (\u0026ldquo;diel rhythm\u0026rdquo; or \u0026ldquo;time of day\u0026rdquo; or \u0026ldquo;time-of-day\u0026rdquo; or \u0026ldquo;exercise timing\u0026rdquo; or \u0026ldquo;circadian\u0026rdquo; or \u0026ldquo;morning vs afternoon\u0026rdquo; or \u0026ldquo;morning vs evening\u0026rdquo; or \u0026ldquo;timing\u0026rdquo; or \u0026ldquo;morning\u0026rdquo; or \u0026ldquo;afternoon\u0026rdquo; or \u0026ldquo;evening\u0026rdquo;). The \u0026ldquo;randomized controlled trial\u0026rdquo; filter was applied in PubMed and Embase databases, and the term \u0026ldquo;clinical trial\u0026rdquo; was added to the WOS search. The search results were imported into EndNote to organize the references and remove duplicates.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2 Eligibility criteria\u003c/h2\u003e\n \u003cp\u003eThe studies were selected for further analysis based on the following inclusion criteria: (a) The research design included exercise programs that involved morning, afternoon, or morning and evening sessions, as well as morning, afternoon, and evening sessions. (b) Outcome indicators encompassed blood glucose, blood lipids, or body composition. Studies that used animal models or special populations, such as adolescents, pregnant women, and patients with HTN, were excluded. Each article was independently screened and approved based on the inclusion and exclusion criteria.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e2.3 Data extraction, conversion, and synthesis\u003c/h2\u003e\n \u003cp\u003eThe extracted data included: (1) body weight, (2) body mass index (BMI), (3) fat mass, (4) fat-free mass, (5) waist circumference, (6) body fat, (7) fasting blood glucose (FBG), (8) hemoglobin A1c (HbA1c) (%), (9) fasting insulin, (10) insulin resistance (HOMA-IR), (11) TG, (12) total cholesterol (TC), (13) high-density lipoproteins (HDL), (14) and low-density lipoproteins (LDL) in long-term studies. FBG and post-exercise blood glucose levels were included in acute studies. The results were extracted using Origin 2025 when they were shown only in graphs, and the corresponding authors could not be reached. If the studies only presented 95% confidence intervals (CIs), standard deviations (SDs) were calculated using the \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.math.hkbu.edu.hk/~tongt/papers/median2mean.html\u003c/span\u003e\u003c/span\u003e website\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. When \u0026Delta;SD was not reported, it was calculated by assuming a correlation coefficient of 0.7, as previously suggested\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n \u003cp\u003e\u003cimg 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\" width=\"666\" height=\"64\"\u003e\u003c/p\u003e\n \u003cp\u003eThe meta-analysis progression was carried out using RevMan5.4 software, using the mean difference (MD) as the measurement data-effect indicator. The criteria for heterogeneity were as follows: I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026lt;\u0026thinsp;50% indicated that the heterogeneity of the articles was low and the fixed-effects model was used for analysis; I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;\u0026gt;\u0026thinsp;50% indicated that the articles had high heterogeneity. The random-effects model was used to analyze articles with high heterogeneity\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e2.4 Risk of bias and methodological quality\u003c/h2\u003e\n \u003cp\u003eThe risk of bias was assessed according to version 2 of the Cochrane tool (RoB2)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e, which consists of six domains: randomization process, intended interventions, missing outcome data, outcome, reported results, and overall bias. This study used the RoB2 Assessment Form to generate visual representations of the risk of bias to enhance the transparency and comprehension of the risk of bias across the reviewed literature.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003e2.5 Sensitivity analysis\u003c/h2\u003e\n \u003cp\u003eFor the sensitivity analysis, the leave-one-out method was used to assess whether any of the included studies had a significant influence on the overall effect. If the leave-one-out test yielded positive results, the effect size of the model was reported, and that particular study was excluded from the analysis.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003e2.6 Quality assessment\u003c/h2\u003e\n \u003cp\u003ePublication bias pertains to the tendency of significant results to be more likely to be published than null results. Publication bias was assessed by visual inspection of funnel plots and the accompanying Egger\u0026rsquo;s tests\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3 Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 Description of studies\u003c/h2\u003e\n \u003cp\u003eTables \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e present qualitative descriptions of the included studies. Thirteen long-term and 5 acute studies were analyzed. In the 13 long-term studies that included 658 participants, the exercise intervention time ranged from 2 to 16 weeks (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Three studies focused on patients with T2D: one on patients with cardiovascular artery disease, two on healthy people, six on healthy overweight and obese people, and one on patients with metabolic syndrome (MetS). In terms of exercise intervention protocols, the studies included one study using strength training, two using combined aerobic and strength training, one using low-intensity walking, three using high-intensity interval training (HIIT), five\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eQualitative analysis of the included Long term studies\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSubject\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eStudy design\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExercise Protocol\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFrequency\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTraining duration\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTime of training\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDiet\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eResults\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCarrillo et al.2024\u003csup\u003e27\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18 T2D subjects (9 M)\u003c/p\u003e\n \u003cp\u003e61\u0026thinsp;\u0026plusmn;\u0026thinsp;2yr\u003c/p\u003e\n \u003cp\u003eBMI:30.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized crossover exercise(2 weeks wash-out)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 min walking at 70% max-HR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning:7:00\u0026ndash;10:00\u003c/p\u003e\n \u003cp\u003eAfternoon:16:00\u0026ndash;19:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning moderate intensity exercise acutely reduces glycaemia in people with type 2 Diabetes also being prescribed metformin.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePalomo et al.2023\u003csup\u003e28\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e139 MetS subjects (90 M)\u003c/p\u003e\n \u003cp\u003e57 yr\u003c/p\u003e\n \u003cp\u003eBMI:30.6 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHIIT: 4 \u0026times; 4 min intervals at 90% of HRmax\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning:8:00\u0026ndash;9:00\u003c/p\u003e\n \u003cp\u003eAfternoon:16:00\u0026ndash;17:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habits\u003c/p\u003e\n \u003cp\u003eEat an hour before exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHigh-intensity aerobic exercise training in the morning is more efficient at reducing cardiometabolic risk factors\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBrooker et al.2023\u003csup\u003e29\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e65 obesity subjects\u003c/p\u003e\n \u003cp\u003eAMEx: 41\u0026thinsp;\u0026plusmn;\u0026thinsp;12\u0026nbsp;year BMI:31\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003ePMEx༚38\u0026thinsp;\u0026plusmn;\u0026thinsp;11\u0026nbsp;year BMI:32\u0026thinsp;\u0026plusmn;\u0026thinsp;5.9kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThree-armed randomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e250 min per week of self-paced aerobic exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e250min/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning:6:00\u0026ndash;9:00\u003c/p\u003e\n \u003cp\u003eAfternoon:16:00\u0026ndash;19:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAfternoon group had a more significant weight loss than the morning group.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCreasy et al. 2022\u003csup\u003e30\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33 obesity subjects (10 M)\u003c/p\u003e\n \u003cp\u003eAM: 40.8\u0026thinsp;\u0026plusmn;\u0026thinsp;8.4\u0026nbsp;year BMI༚30.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003ePM༚36.4\u0026thinsp;\u0026plusmn;\u0026thinsp;10.8yrBMI༚30.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFrom 70\u0026ndash;80% heart rate maximum and 750\u0026ndash;2000 kcal/week supervised aerobic exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 on-own, 3 supervised sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 06:00\u0026ndash;10:00\u003c/p\u003e\n \u003cp\u003eAfternoon: 15:00\u0026ndash;19:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEat freely throughout the study\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAfternoon exercise loses more weight\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTeo et al.2021\u003csup\u003e31\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40 obesity subjects (17 M)\u003c/p\u003e\n \u003cp\u003e51\u0026thinsp;\u0026plusmn;\u0026thinsp;13yr\u003c/p\u003e\n \u003cp\u003eBMI:30.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 minutes of aerobic exercise at 70% VO2peak and 30 minutes of resistance exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 08:00\u0026ndash;10:00\u003c/p\u003e\n \u003cp\u003eAfternoon 17:00\u0026ndash;19:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEatl at least 1h before training\u003c/p\u003e\n \u003cp\u003eMaintain normal eating habit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIn the absence of dietary manipulation, the effect of diurnal exercise timing on body composition appear trivial.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTeo et al.2020\u003csup\u003e32\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40 obesity subjects (17 M)\u003c/p\u003e\n \u003cp\u003e51\u0026thinsp;\u0026plusmn;\u0026thinsp;13yr\u003c/p\u003e\n \u003cp\u003eBMI:30.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled triaL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eModerate intensity (30 minutes of treadmill walking at 60\u0026ndash;70% of VO2 peak)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning :08:00\u0026ndash;10:00 Afternoon :17:00\u0026ndash;19:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain usual eating habits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePmEX group conveyed no statistical improvement in glycemic,insulin sensitivity versus amEX group\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBrooker et al.2019\u003csup\u003e33\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20 inactive, overweight subjects (6 M)\u003c/p\u003e\n \u003cp\u003e39\u0026thinsp;\u0026plusmn;\u0026thinsp;13yr\u003c/p\u003e\n \u003cp\u003eBMI:30.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThree-armed, randomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSelf-paced moderate-vigorous walking or running on a treadmill to achieve a weekly total of 250 min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e250min/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning:06:00\u0026ndash;09:00\u003c/p\u003e\n \u003cp\u003eAfternoon: 16:00\u0026ndash;19:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAfternoon exercise improves body composition and lowers blood glucose\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlizadeh et al.2017\u003csup\u003e34\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e48 overweight females\u003c/p\u003e\n \u003cp\u003eAMEx: 33.56\u0026thinsp;\u0026plusmn;\u0026thinsp;5.98yr\u003c/p\u003e\n \u003cp\u003eBMI:27.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.52kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003ePMEx: 33.89\u0026thinsp;\u0026plusmn;\u0026thinsp;6.58yr\u003c/p\u003e\n \u003cp\u003eBMI:27.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.42kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAerobic exercise at a target heart rate on the ventilatory threshold for 30mins\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 08:00\u0026ndash;10:00\u003c/p\u003e\n \u003cp\u003eAfternoon:14:00\u0026ndash;16:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habit\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAerobic exercise in the morning could be considered a more effective programme than evening exercise on weight loss\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSavikj et al.2022\u003csup\u003e35\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 T2D subjects (8 M)\u003c/p\u003e\n \u003cp\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;8yr\u003c/p\u003e\n \u003cp\u003eBMI:27.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized crossover trial (2 weeks wash-out)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSix one-minute pulses at individual maximal load and 75 rpm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 08:00\u003c/p\u003e\n \u003cp\u003eAfternoon:16:45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTraining\u0026apos;s impact on metabolic parameters was not observed\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLian et al.2014\u003csup\u003e36\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e178 subjects with CAD (133 M)\u003c/p\u003e\n \u003cp\u003eMorning group:64\u0026thinsp;\u0026plusmn;\u0026thinsp;9\u0026nbsp;year\u003c/p\u003e\n \u003cp\u003eBMI:24.97\u0026thinsp;\u0026plusmn;\u0026thinsp;2.71kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003eEvening group:62\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u0026nbsp;year\u003c/p\u003e\n \u003cp\u003eBMI:24.59\u0026thinsp;\u0026plusmn;\u0026thinsp;2.66kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWalk at the speed of 2.5 miles/h for 30 min/day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5 days/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNot stated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAll participants were given similar dietary advice by dietitians\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEvening walking group gained more benefits in lipids.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eArciero et al.2022\u003csup\u003e18\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27 exercise-trained women: 42\u0026thinsp;\u0026plusmn;\u0026thinsp;8yr\u003c/p\u003e\n \u003cp\u003eBMI:24\u0026thinsp;\u0026plusmn;\u0026thinsp;3 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e20 exercise-trained\u003c/p\u003e\n \u003cp\u003emen: 45\u0026thinsp;\u0026plusmn;\u0026thinsp;8yr\u003c/p\u003e\n \u003cp\u003eBMI:25.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRISE training for 1h\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 06:00\u0026ndash;08:00\u003c/p\u003e\n \u003cp\u003eAfternoon:18:30\u0026thinsp;\u0026minus;\u0026thinsp;20:30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMen: TC,HDL declined significantly in PM in\u003c/p\u003e\n \u003cp\u003eWomen: Both AM and PM groups reduced total body fat, increased fat-free mass\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKrčm\u0026aacute;rov\u0026aacute;\u003c/p\u003e\n \u003cp\u003eet al.2018\u003csup\u003e37\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31 women 66\u0026thinsp;\u0026plusmn;\u0026thinsp;4 yr\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eProgressive strength-training for\u003c/p\u003e\n \u003cp\u003e8 exercises, with 3 sets for each exercise, and 10\u0026ndash;12 repetitions per set.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 07:30 Afternoon: 18:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFollow a diet plan,no significant change in energy intake\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSimilar circadian effects of exercise on muscle strength and blood glucose\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSavikj et al.2019\u003csup\u003e35\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11 T2D subjects (11 M)\u003c/p\u003e\n \u003cp\u003e60\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026nbsp;year BMI: 27.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized crossover trial (2 weeks wash-out)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHIIT: on cycle-ergometer 6 \u0026times; 1 min at maximal load\u0026thinsp;+\u0026thinsp;1 min low load\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 sessions/week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 weeks\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 08:00\u003c/p\u003e\n \u003cp\u003eAfternoon : 16:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStandardized snack was offered 30 minutes after the afternoon training,no significant change in energy intake\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAfternoon HIIT reduced glucose concentration\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003ctable id=\"Tab2\" border=\"1\" class=\"fr-table-selection-hover\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eQualitative analysis of the included Acute studies\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSubjects\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eStudy design\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExercise protocol\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTraining duration\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTime of training\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDiet\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eResults\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKim et al.2022\u003csup\u003e38\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 healthy young men\u003c/p\u003e\n \u003cp\u003e21.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2yr\u003c/p\u003e\n \u003cp\u003eBMI: 21.3 kg/m\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized crossover trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60 min on a treadmill at 60% VO\u003csub\u003e2\u003c/sub\u003emax for 3 sessions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 week\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 09:00\u0026ndash;11:00\u003c/p\u003e\n \u003cp\u003eAfternoon : 16:00\u0026ndash;18:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMaintain normal eating habits\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEndurance exercise in the late afternoon was more effective in improving blood sugar and lipid levels over a 24-hour period\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMoholdt et al.2021\u003csup\u003e39\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24 obesity participants (24 M)\u003c/p\u003e\n \u003cp\u003e35-36yr\u003c/p\u003e\n \u003cp\u003eBMI:31.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3 kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThree-armed randomized controlled trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDAY 1,3,5: HIT, 10 \u0026times; 1-min work-bouts and 1-min low-intensity cycling\u003c/p\u003e\n \u003cp\u003eDAY 2,4: 40、60 min of moderate-intensity continuous cycling.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5 days\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 06:30\u003c/p\u003e\n \u003cp\u003eAfternoon: 18:30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11days of high-fat diet before and during exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFasting blood glucose, insulin, cholesterol, triacylglycerol, and LDL-cholesterol concentrations decrease in afternoon exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTanaka et al.2021\u003csup\u003e40\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11 healthy young men\u003c/p\u003e\n \u003cp\u003e22-30yr\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized crossover trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60% of ̇VO2max for 1 h using a cycle ergometer for 4 sessions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 07:00\u003c/p\u003e\n \u003cp\u003eAfternoon ༚16:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eExperimental meals\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGlucose levels during exercise were only decreased in the afternoon exercise trial\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMunan et al.2020\u003csup\u003e41\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14 T2D participants (8 M)\u003c/p\u003e\n \u003cp\u003e65\u0026thinsp;\u0026plusmn;\u0026thinsp;9.0yr\u003c/p\u003e\n \u003cp\u003eBMI: 27.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5 kg/m\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized crossover trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50 min of walking at a speed of 5.0 km/h for 4 sessions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12days\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: exercise ending 20 min before breakfast\u003c/p\u003e\n \u003cp\u003eAfternoon༚starting 3 or 4 hours after lunch and ending 20 min before dinner\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStandardized meals are provided on the exercise day and the following day to ensure energy balance.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe decrease in blood glucose was more pronounced in the afternoon exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eToghi-Eshghi et al.2019\u003csup\u003e42\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 T1D participants (3 M)\u003c/p\u003e\n \u003cp\u003e31.3\u0026nbsp;year BMI: 26.6 kg/m\u0026sup2;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRandomized crossover trial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40 min of RE at 8RM load for 2 sessions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026ge;\u0026thinsp;48 hours between 2 tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning: 07:00\u003c/p\u003e\n \u003cp\u003eAfternoon ༚17:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMorning training: fasting state\u003c/p\u003e\n \u003cp\u003ebefore the afternoon training༚standardized snack at 16:00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBlood glucose decreased after the afternoon exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eBMI, body mass index; T2D, type 2 diabetes; T1D, type 1 diabetes; yr, years\u003c/p\u003e\n \u003cp\u003eusing aerobic training, and one using a multi-sport training model. Finally, three studies used a crossover design with 2-week washout periods, and 10 used a randomized controlled trial (RCT) design.\u003c/p\u003e\n \u003cp\u003eIn the five acute studies shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e, which included 73 participants, the exercise intervention time ranged from 40 to 60 min, and exercise period varied from 1 to 12 days. Among selected studies, two were conducted on healthy individuals, one on participants with obesity, one on patients with T2D, and one on type 1 diabetes (T1D). In terms of exercise intervention protocols, one study implemented a low-intensity walking program, one used HIIT, three employed aerobic training, and one a resistance training program. Regarding the study design, four studies adopted a crossover design, and one utilized an RCT scheme. Notably, Aricero et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e reported data from male and female participants, whereas Teo et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e reported data from patients with T2D and healthy individuals.\u003c/p\u003e\n \u003cp\u003eIn terms of diet, Carrillo et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e enrolled 18 patients with T2D who walked at 70% of their maximum heart rate for 3 to 6 min in the morning and afternoon, maintaining their daily eating habits. Caloric intake for breakfast, lunch, and dinner did not differ significantly during the trial period. Brooker et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e conducted a study on 65 patients with obesity who maintained a controlled diet. After 12 weeks, both the AMEx and PMEx groups showed a reduction in total energy intake during the intervention period. A significant difference was observed in these groups compared with the control group (AMEx \u0026minus;\u0026thinsp;3974 kJ, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; PMEx \u0026minus;\u0026thinsp;3165 kJ, p\u0026thinsp;=\u0026thinsp;0.001). Protein intake in the AMEx group was significantly decreased in the middle and later stages (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), whereas total fat intake in the PMEx group significantly decreased in the later stages (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Similarly, Teo et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e included 40 patients with obesity and observed significant reductions in total energy intake in both groups; however, Alizadeh et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e noted a significant reduction in total energy intake over 6 weeks (p\u0026thinsp;=\u0026thinsp;0.06) in the MT group among 48 women with obesity. In contrast, the AT group did not experience a significant change in total energy intake.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Body composition\u003c/h2\u003e\n \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e\n \u003ch2\u003e3.2.1 Body weight\u003c/h2\u003e\n \u003cp\u003eSix studies across seven different populations assessed body weight. No differences were observed between AT and MT in reducing body weight (MD -0.38, 95% CI -0.96 to 0.09, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.19). The Egger test result was not significant (p\u0026thinsp;=\u0026thinsp;0.907) (Supplementary Fig.\u0026nbsp;1). Leave-one-out analysis showed that none of the studies influenced this effect.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\n \u003ch2\u003e3.2.2 BMI\u003c/h2\u003e\n \u003cp\u003eBMI was evaluated in four studies involving four different populations. No differences were noted between AT and MT in reducing BMI (MD -0.2, 95% CI -0.59 to 0.19, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;67%, p\u0026thinsp;=\u0026thinsp;0.32). Publication bias was not detected (p\u0026thinsp;=\u0026thinsp;0.613) (Supplementary Fig.\u0026nbsp;2). Leave-one-out analysis revealed that any study did not influence the overall outcome.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\n \u003ch2\u003e3.2.3 Fat mass\u003c/h2\u003e\n \u003cp\u003eSeven studies involving eight populations evaluated fat mass. The results showed no differences between AT and MT in reducing fat mass (MD 0.31, 95% CI -0.28 to 0.90, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.3). The Egger test result was not significant (p\u0026thinsp;=\u0026thinsp;0.871) (Supplementary Fig.\u0026nbsp;3). Sensitivity analysis showed consistent results across studies.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e\n \u003ch2\u003e3.2.4 Fat-free mass\u003c/h2\u003e\n \u003cp\u003eThe fat-free mass was evaluated in six studies involving seven different populations. No differences were observed between AT and MT in reducing fat-free mass (MD 0.14, 95% CI -0.35 to 0.64, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.57). The Egger test indicated no publication bias (p\u0026thinsp;=\u0026thinsp;0.973) (Supplementary Fig.\u0026nbsp;4). Leave-one-out analysis confirmed that individual studies did not affect the outcome.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e\n \u003ch2\u003e3.2.5 Body fat\u003c/h2\u003e\n \u003cp\u003eFive studies across six different populations investigated body fat. MT reduced body fat more effectively than AT (MD -0.39, 95% CI -0.66 to -0.13, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.004). No publication bias was observed (p\u0026thinsp;=\u0026thinsp;0.973) (Supplementary Fig.\u0026nbsp;5). However, leave-one-out analysis showed that removing the study by Alizadeh et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e nullified the significant advantage of MT (MD 0.27, 95% CI -0.39 to 0.94, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.42).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e\n \u003ch2\u003e3.2.6 Waist circumference\u003c/h2\u003e\n \u003cp\u003eWaist circumference was evaluated in four studies involving four different populations. MT was more effective than AT at reducing waist circumference (MD -0.53, 95% CI -1.06 to -0.00, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;31%, p\u0026thinsp;=\u0026thinsp;0.05). Subgroup analysis indicated that aerobic exercise was more beneficial than mixed resistance-aerobic routines. The Egger showed no publication bias (p\u0026thinsp;=\u0026thinsp;0.914) (Supplementary Fig.\u0026nbsp;6). However, the effect was no longer significant when the study by Alizadeh et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e was excluded (MD 0.67, 95% CI -0.63 to 1.96, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.31).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\n \u003ch2\u003e3.3 Glycemic control\u003c/h2\u003e\n \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.1 FBG\u003c/h2\u003e\n \u003cp\u003eEight studies involving 10 populations analyzed FBG, and AT reduced FBG more effectively than MT (MD 0.13, 95% CI -0.01 to 0.24, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.03). Subgroup analysis found no significant difference in the duration of exercise required to lower blood sugar levels between patients with and without diabetes. The Egger test result was significant (p\u0026thinsp;=\u0026thinsp;0.034) (Supplementary Fig.\u0026nbsp;7). Leave-one-out analysis showed that the results were no longer significantly biased in favor of AT for reducing blood glucose after excluding the studies by Brooker et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e and Savikj et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n \u003cp\u003eIn the acute studies, three studies involving three populations evaluated FBG levels; no differences were observed between AT and MT in terms of reducing glucose levels (MD -0.72, 95% CI -2.12 to 0.67, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;98%, p\u0026thinsp;=\u0026thinsp;0.31). The Egger test result was significant (p\u0026thinsp;=\u0026thinsp;0.334) (Supplementary Fig.\u0026nbsp;8). Leave-one-out analysis showed stable outcomes across studies.\u003c/p\u003e\n \u003cp\u003eBlood glucose differences before and after exercise were also evaluated in three studies with three different populations. AT was more effective than MT at reducing FBG (MD 0.53, 95% CI 0.32 to 0.73, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;21%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Publication bias was marginal (p\u0026thinsp;=\u0026thinsp;0.075) (Supplementary Fig.\u0026nbsp;9). However, when excluding the study by Tanaka et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e, the results were no longer significantly biased in favor of AT to reduce the blood glucose difference before and after exercise (MD 0.48, 95% CI -0.36 to 1.33, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;60%, p\u0026thinsp;=\u0026thinsp;0.26).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.2 HbA1c\u003c/h2\u003e\n \u003cp\u003eHbA1c was evaluated in four studies involving distinct populations, and MT was more effective than AT at reducing HbA1c (MD -0.11, 95% CI -0.19 to -0.03, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.009) (Supplementary Fig.\u0026nbsp;10). The Egger test revealed no publication bias (p\u0026thinsp;=\u0026thinsp;0.46). Sensitivity analysis indicated that when excluding the study by Teo et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e, the results were no longer significantly biased in favor of MT in reducing HbA1c.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.3 Fasting insulin\u003c/h2\u003e\n \u003cp\u003eFasting insulin was described in five studies with seven different populations. There were no differences between AT and MT in reducing insulin levels (MD 0.09, 95% CI -0.37 to 0.54, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.71). The Egger test was not significant (p\u0026thinsp;=\u0026thinsp;0.056) (Supplementary Fig.\u0026nbsp;11). The leave-one-out analysis showed that none of the studies was influencing the effect.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec22\" class=\"Section3\"\u003e\n \u003ch2\u003e3.3.4 HOMA-IR\u003c/h2\u003e\n \u003cp\u003eHOMA-IR was described in three studies with four different populations. There were no differences between AT and MT in reducing HOMA-IR levels (MD 0.02, 95% CI -0.21 to -0.16, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.8). The Egger test was not significant (p\u0026thinsp;=\u0026thinsp;0.284) (Supplementary Fig.\u0026nbsp;12). The leave-one-out analysis showed that none of the studies was influencing the effect.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec23\" class=\"Section2\"\u003e\n \u003ch2\u003e3.4 Blood Lipids\u003c/h2\u003e\n \u003cdiv id=\"Sec24\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.1 TG\u003c/h2\u003e\n \u003cp\u003eAnalysis of TG across nine independent population studies demonstrated AT tended to be more effective than MT at reducing TG (MD 0.1, 95% CI 0.02 to 0.18, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;41%, p\u0026thinsp;=\u0026thinsp;0.02). Publication bias assessment through Egger\u0026apos;s test yielded non-significant results (p\u0026thinsp;=\u0026thinsp;0.188) (Supplementary Fig.\u0026nbsp;13). The leave-one-out analysis showed when excluding studies of Krčm\u0026aacute;rov\u0026aacute; et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e or Lian et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e, the model the effect size rose to almost a trend towards a better effect for AT.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.2 TC\u003c/h2\u003e\n \u003cp\u003eTC was evaluated in seven studies with eight different populations. There were no differences between AT and MT to reduce TC levels (MD 0.02, 95% CI -0.08 to 0.05, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;36%, p\u0026thinsp;=\u0026thinsp;0.61). The Egger test was not significant (p\u0026thinsp;=\u0026thinsp;0.517) (Supplementary Fig.\u0026nbsp;14). The leave-one-out analysis showed that none of the studies was influencing the effect.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec26\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.3 HDL\u003c/h2\u003e\n \u003cp\u003eHDL was evaluated in eight studies with nine different populations. We found that AT tended to be more effective than MT at reducing HDL (MD 0.04, 95% CI -0.00 to 0.09, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;11%, p\u0026thinsp;=\u0026thinsp;0.06). The Egger test was not significant (p\u0026thinsp;=\u0026thinsp;0.864) (Supplementary Fig.\u0026nbsp;15). The leave-one-out analysis showed that the study by Brooker et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e was influencing the results. When leaving this study out of the analysis, the effects of the model showed that afternoon exercise was more efficient in lowering HDL levels (MD 0.05, 95% CI 0.00 to 0.10, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;1%, p\u0026thinsp;=\u0026thinsp;0.03). The study by Krčm\u0026aacute;rov\u0026aacute; et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e was influencing the results. When leaving this study out of the analysis, the effects of the model showed that afternoon exercise was more efficient in lowering HDL levels (MD 0.05, 95% CI 0.00 to 0.10, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0%, p\u0026thinsp;=\u0026thinsp;0.04). Furthermore, the study by Lian et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e influenced the results. When leaving this study out of the analysis, the effects of the model showed that afternoon exercise was more efficient in lowering HDL levels (MD 0.06, 95% CI 0.01 to 0.11, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;3%, p\u0026thinsp;=\u0026thinsp;0.02).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec27\" class=\"Section3\"\u003e\n \u003ch2\u003e3.4.4 LDL\u003c/h2\u003e\n \u003cp\u003eLDL was evaluated in eight studies with nine different populations. No differences between AT and MT in reducing LDL levels (MD -0.06, 95% CI -0.13 to 0.01, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;19%, p\u0026thinsp;=\u0026thinsp;0.09) were observed. The Egger test was not significant (p\u0026thinsp;=\u0026thinsp;0.300) (Supplementary Fig.\u0026nbsp;16). The leave-one-out analysis showed that the study by Savikj et al.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e was influencing the results. When leaving this study out of the analysis, the effects of the model were biased to show that morning exercise was more efficient in lowering LDL levels (MD -0.08, 95% CI -0.15 to 0.00, I\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;15%, p\u0026thinsp;=\u0026thinsp;0.05).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eThis meta-analysis highlights the distinct effects of MT and AT on body composition, glycemic control, and lipid metabolism. AT showed better outcomes in reducing TG and FBG levels, whereas MT was more effective in reducing body fat, waist circumference, and HbA1c. These results highlight the role of exercise timing and circadian rhythms in metabolic health.\u003c/p\u003e\u003cp\u003eExercise can reduce obesity, and this study showed that MT had a greater effect on body fat and waist circumference than AT, consistent with previous studies. For example, one study found that those who exercised moderately to vigorously between 7 and 9 AM had a lower BMI than those who exercised during the middle of the day or at night\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e. A cross-sectional analysis of the health of 7,157 women suggested that those who exercised less in the morning may have a higher risk of obesity\u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. Similarly, consistent MT improved exercise adherence and weight management in overweight or obese individuals\u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe analysis of glycemic markers revealed that mid-to-long-term AT more effectively improved FBG, whereas MT showed greater benefits for reducing HbA1c. AT may acutely improve FBG levels by aligning with circadian insulin sensitivity peaks, whereas MT enhances long-term HbA1c levels through sustained metabolic adaptations, such as improved insulin sensitivity and fat oxidation. Additionally, the HbA1c analysis may have included more people with T2D, whereas the FBG analysis may have covered a broader population, including healthy people and people with diabetes. Similarly, Mancilla et al. investigated 32 adult males at risk for or diagnosed with T2D and found that AT improved FBG levels better than MT\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e. However, a recent randomized controlled trial showed that moderate exercise in the morning significantly reduced FBG in patients with T2D who took metformin and that the glucose area under the curve values was significantly reduced only in the case of MT and taking metformin before breakfast\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. These results suggest an association between MT and the time of taking metformin to affect blood glucose levels. In the acute studies analyzed, blood glucose levels consistently showed improvement after AT.\u003c/p\u003e\u003cp\u003eAT to improve TG was an important finding in this study and is consistent with the results of a recent meta-analysis\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. However, a cross-sectional study of 51 older adults showed that MT tended to lower LDL and may be more beneficial to lowering blood lipids than AT\u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e\u003c/sup\u003e. This discrepancy may be because the average age of the participants included in this study was 71.8 years, and the effect of exercise on blood lipid improvement differed between age groups.\u003c/p\u003e\u003cp\u003eThe possible mechanisms underlying these results may include MT-induced stimulation of the sympathetic nervous system, leading to increased catecholamine secretion. These hormones enhance lipolysis and elevate energy expenditure by activating β-adrenergic receptors in adipose tissue and skeletal muscle. MT has also been associated with a prolonged increase in resting metabolic rate, reflecting the energy required for basic physiological functions at rest. Exercise promotes the formation of new mitochondria, thereby enhancing cellular energy production and utilization\u003csup\u003e\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e. Additionally, human skeletal muscular strength and mitochondrial function typically peak in during AT, which may more effectively regulate blood sugar glucose levels by enhancing glucose uptake and utilization by muscle tissue\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAlthough this study provides a systematic review and meta-analysis of the effects of exercise duration on metabolic health, some limitations should be addressed. First, variation in baseline health and age across study participants may have affected the consistency of the results. Second, the duration of the included medium- and long-term studies was limited, and acute studies were even fewer, which may have affected the robustness of the results. Third, the sensitivity analyses may be biased owing to the insufficient number of studies included.\u003c/p\u003e"},{"header":"5 Conclusion","content":"\u003cp\u003eMT and AT yield distinct metabolic benefits. Specifically, MT was more effective in reducing body fat percentage and waist circumference and improving HbA1c levels, whereas AT showed superior results in regulating FBG and lowering TG levels. The differential effects of MT and AT observed in this study have practical implications for personalized exercise interventions. AT may offer more pronounced benefits for individuals who aim to improve glycemic control, especially those with insulin resistance or elevated FBG. In contrast, MT may be used by those focusing on fat loss and weight management. Incorporating exercise timing into clinical guidelines could enhance the effectiveness of lifestyle interventions for metabolic disorders. However, future research should explore the effects of exercise on metabolic health at different times before or after meals, as well as the immediate and long-term effects of exercise of different intensities, durations, and frequencies in different populations. In addition, future studies should consider more demographic factors, such as sex, age, and health status, to better understand the influence of exercise timing on metabolic health.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e1. T2D: Type 2 Diabetes \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e2. HTN: Hypertension \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e3. MetS: Metabolic Syndrome \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e4. MT: Morning Training \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e5. AT: Afternoon Training \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e6. TG: Triglycerides \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e7. PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e8. PROSPERO: International Prospective Register of Systematic Reviews \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e9. WOS: Web of Science \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e10. RCT: Randomized Controlled Trial \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e11. BMI: Body Mass Index \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e12. FBG: Fasting Blood Glucose \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e13. HbA1c: Hemoglobin A1c \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e14. HOMA-IR: Homeostatic Model Assessment for Insulin Resistance \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e15. TC: Total Cholesterol \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e16. HDL: High-Density Lipoproteins \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e17. LDL: Low-Density Lipoproteins \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e18. SD: Standard Deviation \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e19. MD: Mean Deviation \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e20. CI: Confidence Interval \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e21. HIIT: High-Intensity Interval Training \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e22. VO2: Volume of Oxygen \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e23. T1D: Type 1 Diabetes \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e24. CAD: Coronary Artery Disease\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e1. Ethics approval and consent to participate Consent for publication\u003c/p\u003e\n\u003cp\u003eNot Applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e2. Consent for publication\u003c/p\u003e\n\u003cp\u003eAll authors have provided their consent for publication.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e3. Availability of data and material\u003c/p\u003e\n\u003cp\u003eNot Applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e4.Competing interests\u003c/p\u003e\n\u003cp\u003eThis article has no financial or non-financial competing interests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e5.Funding\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National Natural Science Foundation of China [Grant Number 32400953].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e6. Authors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eJW: Conceptualization, Investigation, Data curation, Writing, original draft.\u003cbr\u003e\u0026nbsp;SC: Methodology, Formal analysis, Validation, Writing, review \u0026amp; editing.\u003cbr\u003e\u0026nbsp;ZZ: Software, Visualization, Investigation, Data curation.\u003cbr\u003e\u0026nbsp;BY: Resources, Writing, review \u0026amp; editing, Supervision.\u003cbr\u003e\u0026nbsp;XZ: Supervision, Project administration, Funding acquisition, Writing, review \u0026amp; editing (Corresponding author).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e7. Acknowledgements\u003c/p\u003e\n\u003cp\u003eThank to all the authors whose work contributed to this meta-analysis. Their researches and willingness to share data were essential for our findings and advancing knowledge in this field.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eChaves, S. F. N., Silva Ara\u0026uacute;jo, D. P. da, Guilherme, L. Q. \u0026amp; Agostinho, P. A. G. Diagnosis, physiological mechanisms, risk factors, treatment and prevention of obesity: A brief commentary. \u003cem\u003eObes. Med.\u003c/em\u003e \u003cstrong\u003e52\u003c/strong\u003e, 100572 (2024).\u003c/li\u003e\n\u003cli\u003eSun, X. \u003cem\u003eet al.\u003c/em\u003e Expert Consensus and Call on Actions for Weight Management in China: Advancing Healthy China Initiative Through Strategic Actions. \u003cem\u003eChina CDC Wkly.\u003c/em\u003e \u003cstrong\u003e6\u003c/strong\u003e, 1347\u0026ndash;1353 (2024).\u003c/li\u003e\n\u003cli\u003ede Mello, A. H., Pr\u0026aacute;, M., Cardoso, L. C., de Bona Schraiber, R. \u0026amp; Rezin, G. T. Incretin-based therapies for obesity treatment. \u003cem\u003eMetabolism.\u003c/em\u003e \u003cstrong\u003e64\u003c/strong\u003e, 967\u0026ndash;981 (2015).\u003c/li\u003e\n\u003cli\u003ePeri, K. \u0026amp; Eisenberg, M. Review on the update in obesity management: epidemiology. \u003cem\u003eBMJ Public Health\u003c/em\u003e \u003cstrong\u003e2\u003c/strong\u003e, (2024).\u003c/li\u003e\n\u003cli\u003eCaballero, B. Humans against Obesity: Who Will Win? \u003cem\u003eAdv. Nutr. Bethesda Md\u003c/em\u003e \u003cstrong\u003e10\u003c/strong\u003e, S4\u0026ndash;S9 (2019).\u003c/li\u003e\n\u003cli\u003eChew, N. W. S. \u003cem\u003eet al.\u003c/em\u003e The global burden of metabolic disease: Data from 2000 to 2019. \u003cem\u003eCell Metab.\u003c/em\u003e \u003cstrong\u003e35\u003c/strong\u003e, 414-428.e3 (2023).\u003c/li\u003e\n\u003cli\u003ePedersen, B. K. \u0026amp; Saltin, B. Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases. \u003cem\u003eScand. J. Med. Sci. Sports\u003c/em\u003e \u003cstrong\u003e25 Suppl 3\u003c/strong\u003e, 1\u0026ndash;72 (2015).\u003c/li\u003e\n\u003cli\u003eGabriel, B. M. \u0026amp; Zierath, J. R. The Limits of Exercise Physiology: From Performance to Health. \u003cem\u003eCell Metab.\u003c/em\u003e \u003cstrong\u003e25\u003c/strong\u003e, 1000\u0026ndash;1011 (2017).\u003c/li\u003e\n\u003cli\u003eSchroeder, A. M. \u003cem\u003eet al.\u003c/em\u003e Voluntary scheduled exercise alters diurnal rhythms of behaviour, physiology and gene expression in wild-type and vasoactive intestinal peptide-deficient mice. \u003cem\u003eJ. Physiol.\u003c/em\u003e \u003cstrong\u003e590\u003c/strong\u003e, 6213\u0026ndash;6226 (2012).\u003c/li\u003e\n\u003cli\u003eModerate intensity walking exercises reduce the body mass index and vascular inflammatory factors in postmenopausal women with obesity: a randomized controlled trial | Scientific Reports. https://www.nature.com/articles/s41598-023-47403-2.\u003c/li\u003e\n\u003cli\u003eEglseer, D. \u003cem\u003eet al.\u003c/em\u003e Nutrition and Exercise Interventions to Improve Body Composition for Persons with Overweight or Obesity Near Retirement Age: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials. \u003cem\u003eAdv. Nutr. Bethesda Md\u003c/em\u003e \u003cstrong\u003e14\u003c/strong\u003e, 516\u0026ndash;538 (2023).\u003c/li\u003e\n\u003cli\u003eMotahari-Tabari, N., Ahmad Shirvani, M., Shirzad-E-Ahoodashty, M., Yousefi-Abdolmaleki, E. \u0026amp; Teimourzadeh, M. The effect of 8 weeks aerobic exercise on insulin resistance in type 2 diabetes: a randomized clinical trial. \u003cem\u003eGlob. J. Health Sci.\u003c/em\u003e \u003cstrong\u003e7\u003c/strong\u003e, 115\u0026ndash;121 (2014).\u003c/li\u003e\n\u003cli\u003eSanchis-Gomar, F. \u003cem\u003eet al.\u003c/em\u003e The Acquisition of Cardiovascular Adaptation to Aerobic Exercise: When Does It Begin and How Does It Evolve Depending on Intrinsic and Extrinsic Factors? \u003cem\u003eCan. J. Cardiol.\u003c/em\u003e S0828-282X(24)01320\u0026ndash;5 (2024) doi:10.1016/j.cjca.2024.12.023.\u003c/li\u003e\n\u003cli\u003eRynders, C. A. \u0026amp; Broussard, J. L. Running the clock: new insights into exercise and circadian rhythms for optimal metabolic health. \u003cem\u003eJ. Physiol.\u003c/em\u003e \u003cstrong\u003e602\u003c/strong\u003e, 6367\u0026ndash;6371 (2024).\u003c/li\u003e\n\u003cli\u003eDighriri, A. \u003cem\u003eet al.\u003c/em\u003e The impact of the time of day on metabolic responses to exercise in adults: A systematic and meta-analysis review. \u003cem\u003eChronobiol. Int.\u003c/em\u003e \u003cstrong\u003e41\u003c/strong\u003e, 1377\u0026ndash;1388 (2024).\u003c/li\u003e\n\u003cli\u003eSevilla-Lorente, R., Carneiro-Barrera, A., Molina-Garcia, P., Ruiz, J. R. \u0026amp; Amaro-Gahete, F. J. Time of the day of exercise impact on cardiovascular disease risk factors in adults: a systematic review and meta-analysis. \u003cem\u003eJ. Sci. Med. Sport\u003c/em\u003e \u003cstrong\u003e26\u003c/strong\u003e, 169\u0026ndash;179 (2023).\u003c/li\u003e\n\u003cli\u003eGalan-Lopez, P. \u0026amp; Casuso, R. A. Metabolic Adaptations to Morning Versus Afternoon Training: A Systematic Review and Meta-analysis. \u003cem\u003eSports Med.\u003c/em\u003e \u003cstrong\u003e53\u003c/strong\u003e, 1951\u0026ndash;1961 (2023).\u003c/li\u003e\n\u003cli\u003eArciero, P. J. \u003cem\u003eet al.\u003c/em\u003e Morning Exercise Reduces Abdominal Fat and Blood Pressure in Women; Evening Exercise Increases Muscular Performance in Women and Lowers Blood Pressure in Men. \u003cem\u003eFront. Physiol.\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 893783 (2022).\u003c/li\u003e\n\u003cli\u003eThomas, G. A. \u003cem\u003eet al.\u003c/em\u003e Obesity, growth hormone and exercise. \u003cem\u003eSports Med. Auckl. NZ\u003c/em\u003e \u003cstrong\u003e43\u003c/strong\u003e, 839\u0026ndash;849 (2013).\u003c/li\u003e\n\u003cli\u003ePage, M. J. \u003cem\u003eet al.\u003c/em\u003e The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. \u003cem\u003eRev. Espanola Cardiol. Engl. Ed\u003c/em\u003e \u003cstrong\u003e74\u003c/strong\u003e, 790\u0026ndash;799 (2021).\u003c/li\u003e\n\u003cli\u003eWan, X., Wang, W., Liu, J. \u0026amp; Tong, T. Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range. \u003cem\u003eBMC Med. Res. Methodol.\u003c/em\u003e \u003cstrong\u003e14\u003c/strong\u003e, 135 (2014).\u003c/li\u003e\n\u003cli\u003eLuo, D., Wan, X., Liu, J. \u0026amp; Tong, T. Optimally estimating the sample mean from the sample size, median, mid-range, and/or mid-quartile range. \u003cem\u003eStat. Methods Med. Res.\u003c/em\u003e \u003cstrong\u003e27\u003c/strong\u003e, 1785\u0026ndash;1805 (2018).\u003c/li\u003e\n\u003cli\u003eMason, S. A., Keske, M. A. \u0026amp; Wadley, G. D. Effects of Vitamin C Supplementation on Glycemic Control and Cardiovascular Risk Factors in People With Type 2 Diabetes: A GRADE-Assessed Systematic Review and Meta-analysis of Randomized Controlled Trials. \u003cem\u003eDiabetes Care\u003c/em\u003e \u003cstrong\u003e44\u003c/strong\u003e, 618\u0026ndash;630 (2021).\u003c/li\u003e\n\u003cli\u003eCumpston, M. \u003cem\u003eet al.\u003c/em\u003e Updated guidance for trusted systematic reviews: a new edition of the Cochrane Handbook for Systematic Reviews of Interventions. \u003cem\u003eCochrane Database Syst. Rev.\u003c/em\u003e \u003cstrong\u003e10\u003c/strong\u003e, ED000142 (2019).\u003c/li\u003e\n\u003cli\u003eSterne, J. A. C. \u003cem\u003eet al.\u003c/em\u003e RoB 2: a revised tool for assessing risk of bias in randomised trials. \u003cem\u003eBMJ\u003c/em\u003e \u003cstrong\u003e366\u003c/strong\u003e, l4898 (2019).\u003c/li\u003e\n\u003cli\u003eP\u0026eacute;rez-Rodr\u0026iacute;guez, M., Huertas, J. R., Villalba, J. M. \u0026amp; Casuso, R. A. Mitochondrial adaptations to calorie restriction and bariatric surgery in human skeletal muscle: a systematic review with meta-analysis. \u003cem\u003eMetabolism.\u003c/em\u003e \u003cstrong\u003e138\u003c/strong\u003e, 155336 (2023).\u003c/li\u003e\n\u003cli\u003eCarrillo, B. J. P. \u003cem\u003eet al.\u003c/em\u003e Morning exercise and pre-breakfast metformin interact to reduce glycaemia in people with type 2 diabetes: a randomized crossover trial. \u003cem\u003eJ. Physiol.\u003c/em\u003e (2024) doi:10.1113/JP285722.\u003c/li\u003e\n\u003cli\u003eMorales-Palomo, F. \u003cem\u003eet al.\u003c/em\u003e Efficacy of morning versus afternoon aerobic exercise training on reducing metabolic syndrome components: A randomized controlled trial. \u003cem\u003eJ. Physiol.\u003c/em\u003e \u003cstrong\u003en/a\u003c/strong\u003e,.\u003c/li\u003e\n\u003cli\u003eBrooker, P. G., Gomersall, S. R., King, N. A. \u0026amp; Leveritt, M. D. The efficacy of morning versus evening exercise for weight loss: A randomized controlled trial. \u003cem\u003eObes. Silver Spring Md\u003c/em\u003e \u003cstrong\u003e31\u003c/strong\u003e, 83\u0026ndash;95 (2023).\u003c/li\u003e\n\u003cli\u003eCreasy, S. A. \u003cem\u003eet al.\u003c/em\u003e Effect of Morning and Evening Exercise on Energy Balance: A Pilot Study. \u003cem\u003eNutrients\u003c/em\u003e \u003cstrong\u003e14\u003c/strong\u003e, 816 (2022).\u003c/li\u003e\n\u003cli\u003eTeo, S. Y. M. \u003cem\u003eet al.\u003c/em\u003e Effects of diurnal exercise timing on appetite, energy intake and body composition: A parallel randomized trial. \u003cem\u003eAppetite\u003c/em\u003e \u003cstrong\u003e167\u003c/strong\u003e, 105600 (2021).\u003c/li\u003e\n\u003cli\u003eTeo, S. Y. M., Kanaley, J. A., Guelfi, K. J., Marston, K. J. \u0026amp; Fairchild, T. J. The Effect of Exercise Timing on Glycemic Control: A Randomized Clinical Trial. \u003cem\u003eMed. Sci. Sports Exerc.\u003c/em\u003e \u003cstrong\u003e52\u003c/strong\u003e, 323\u0026ndash;334 (2020).\u003c/li\u003e\n\u003cli\u003eBrooker, P. G., Gomersall, S. R., King, N. A. \u0026amp; Leveritt, M. D. The feasibility and acceptability of morning versus evening exercise for overweight and obese adults: A randomized controlled trial. \u003cem\u003eContemp. Clin. Trials Commun.\u003c/em\u003e \u003cstrong\u003e14\u003c/strong\u003e, 100320 (2019).\u003c/li\u003e\n\u003cli\u003eAlizadeh, Z., Younespour, S., Rajabian Tabesh, M. \u0026amp; Haghravan, S. Comparison between the effect of 6 weeks of morning or evening aerobic exercise on appetite and anthropometric indices: a randomized controlled trial. \u003cem\u003eClin. Obes.\u003c/em\u003e \u003cstrong\u003e7\u003c/strong\u003e, 157\u0026ndash;165 (2017).\u003c/li\u003e\n\u003cli\u003eSavikj, M. \u003cem\u003eet al.\u003c/em\u003e Exercise timing influences multi-tissue metabolome and skeletal muscle proteome profiles in type 2 diabetic patients - A randomized crossover trial. \u003cem\u003eMetabolism.\u003c/em\u003e \u003cstrong\u003e135\u003c/strong\u003e, 155268 (2022).\u003c/li\u003e\n\u003cli\u003eLian, X.-Q. \u003cem\u003eet al.\u003c/em\u003e The influence of regular walking at different times of day on blood lipids and inflammatory markers in sedentary patients with coronary artery disease. \u003cem\u003ePrev. Med.\u003c/em\u003e \u003cstrong\u003e58\u003c/strong\u003e, 64\u0026ndash;69 (2014).\u003c/li\u003e\n\u003cli\u003eKrčm\u0026aacute;rov\u0026aacute;, B. \u003cem\u003eet al.\u003c/em\u003e The effects of 12-week progressive strength training on strength, functional capacity, metabolic biomarkers, and serum hormone concentrations in healthy older women: morning versus evening training. \u003cem\u003eChronobiol. Int.\u003c/em\u003e \u003cstrong\u003e35\u003c/strong\u003e, 1490\u0026ndash;1502 (2018).\u003c/li\u003e\n\u003cli\u003eKim, H.-K. \u003cem\u003eet al.\u003c/em\u003e Late-afternoon endurance exercise is more effective than morning endurance exercise at improving 24-h glucose and blood lipid levels. \u003cem\u003eFront. Endocrinol.\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 957239 (2022).\u003c/li\u003e\n\u003cli\u003eMoholdt, T. \u003cem\u003eet al.\u003c/em\u003e The effect of morning vs evening exercise training on glycaemic control and serum metabolites in overweight/obese men: a randomised trial. \u003cem\u003eDiabetologia\u003c/em\u003e \u003cstrong\u003e64\u003c/strong\u003e, 2061\u0026ndash;2076 (2021).\u003c/li\u003e\n\u003cli\u003eTanaka, Y. \u003cem\u003eet al.\u003c/em\u003e Effect of a single bout of morning or afternoon exercise on glucose fluctuation in young healthy men. \u003cem\u003ePhysiol. Rep.\u003c/em\u003e \u003cstrong\u003e9\u003c/strong\u003e, e14784 (2021).\u003c/li\u003e\n\u003cli\u003eMunan, M. \u003cem\u003eet al.\u003c/em\u003e Does Exercise Timing Affect 24-Hour Glucose Concentrations in Adults With Type 2 Diabetes? A Follow Up to the Exercise-Physical Activity and Diabetes Glucose Monitoring Study. \u003cem\u003eCan. J. Diabetes\u003c/em\u003e \u003cstrong\u003e44\u003c/strong\u003e, 711-718.e1 (2020).\u003c/li\u003e\n\u003cli\u003eToghi-Eshghi, S. R. \u0026amp; Yardley, J. E. Morning (Fasting) vs Afternoon Resistance Exercise in Individuals With Type 1 Diabetes: A Randomized Crossover Study. \u003cem\u003eJ. Clin. Endocrinol. Metab.\u003c/em\u003e \u003cstrong\u003e104\u003c/strong\u003e, 5217\u0026ndash;5224 (2019).\u003c/li\u003e\n\u003cli\u003eSavikj, M. \u003cem\u003eet al.\u003c/em\u003e Afternoon exercise is more efficacious than morning exercise at improving blood glucose levels in individuals with type 2 diabetes: a randomised crossover trial. \u003cem\u003eDiabetologia\u003c/em\u003e \u003cstrong\u003e62\u003c/strong\u003e, 233\u0026ndash;237 (2019).\u003c/li\u003e\n\u003cli\u003eMa, T., Bennett, T., Lee, C.-D. \u0026amp; Wicklow, M. The diurnal pattern of moderate-to-vigorous physical activity and obesity: a cross-sectional analysis. \u003cem\u003eObesity\u003c/em\u003e \u003cstrong\u003e31\u003c/strong\u003e, 2638\u0026ndash;2647 (2023).\u003c/li\u003e\n\u003cli\u003eChomistek, A. K., Shiroma, E. J. \u0026amp; Lee, I.-M. The Relationship Between Time of Day of Physical Activity and Obesity in Older Women. \u003cem\u003eJ. Phys. Act. Health\u003c/em\u003e \u003cstrong\u003e13\u003c/strong\u003e, 416\u0026ndash;418 (2016).\u003c/li\u003e\n\u003cli\u003eSchumacher, L. M., Thomas, J. G., Raynor, H. A., Rhodes, R. E. \u0026amp; Bond, D. S. Consistent Morning Exercise May Be Beneficial for Individuals With Obesity. \u003cem\u003eExerc. Sport Sci. Rev.\u003c/em\u003e \u003cstrong\u003e48\u003c/strong\u003e, 201\u0026ndash;208 (2020).\u003c/li\u003e\n\u003cli\u003eMancilla, R. \u003cem\u003eet al.\u003c/em\u003e Exercise training elicits superior metabolic effects when performed in the afternoon compared to morning in metabolically compromised humans. \u003cem\u003ePhysiol. Rep.\u003c/em\u003e \u003cstrong\u003e8\u003c/strong\u003e, e14669 (2021).\u003c/li\u003e\n\u003cli\u003eKim, H.-K. \u003cem\u003eet al.\u003c/em\u003e Morning physical activity may be more beneficial for blood lipids than afternoon physical activity in older adults: a cross-sectional study. \u003cem\u003eEur. J. Appl. Physiol.\u003c/em\u003e \u003cstrong\u003e124\u003c/strong\u003e, 3253\u0026ndash;3263 (2024).\u003c/li\u003e\n\u003cli\u003eMueller, P. J. Exercise training and sympathetic nervous system activity: evidence for physical activity dependent neural plasticity. \u003cem\u003eClin. Exp. Pharmacol. Physiol.\u003c/em\u003e \u003cstrong\u003e34\u003c/strong\u003e, 377\u0026ndash;384 (2007).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"sports-medicine-open","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"smoa","sideBox":"Learn more about [Sports Medicine-Open](http://sportsmedicine-open.springeropen.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/smoa/default.aspx","title":"Sports Medicine-Open","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Exercise timing, Body composition, Glucose metabolism, Lipid metabolism, Metabolic adaptation","lastPublishedDoi":"10.21203/rs.3.rs-7182337/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7182337/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction:\u003c/strong\u003e\u003cbr\u003e\nExercise, a non-pharmacological intervention, is widely recognized for its beneficial effects on metabolic health. However, the different effects of morning and afternoon exercise on various metabolic indicators remain unclear. Therefore, this study aimed to systematically evaluate and analyze the effect of exercise at various times on body composition, glucose metabolism, and lipid metabolism.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFollowing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, this study conducted a literature search in electronic databases including PubMed, Embase, and Web of Science. The studies included exercise regimens in the morning, afternoon, or morning and evening and analyzed body weight, body mass index, fat mass, fasting blood glucose, hemoglobin A1c (HbA1c), insulin, or triglycerides. The risk of bias was assessed using the Cochrane tool (Rob2), and publication bias was assessed using funnel plots and Egger tests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThirteen long-term and five acute studies were analyzed (n = 658 participants). Morning training was more effective in reducing body fat (mean deviation [MD] -0.39, 95% confidence interval [CI] -0.66 to -0.13, ), waist circumference (MD -0.53, 95% CI -1.06 to -0.00, I\u003csup\u003e2\u003c/sup\u003e = 31%, p = 0.05), and HbA1c (MD -0.11, 95% CI -0.19 to -0.03, I\u003csup\u003e2\u003c/sup\u003e = 0%, p = 0.009), whereas afternoon training was better in lowering fasting blood glucose (MD 0.13, 95% CI 0.01 to 0.24, I\u003csup\u003e2\u003c/sup\u003e = 0%, p = 0.03) and triglycerides (MD 0.1, 95% CI 0.02 to 0.18, I\u003csup\u003e2\u003c/sup\u003e= 41%, p = 0.02).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBoth morning and afternoon training are beneficial for metabolic health; however, their effects differ. Morning training was more likely to reduce body fat, waist circumference, and HbA1c, whereas afternoon exercise was more likely to reduce fasting blood glucose and triglycerides. Incorporating exercise timing into clinical guidelines could enhance the effectiveness of lifestyle interventions for metabolic disorders.\u003c/p\u003e","manuscriptTitle":"Influence of Morning and Afternoon Exercise on Body Composition and Metabolic Health","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-03 23:56:25","doi":"10.21203/rs.3.rs-7182337/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-09-07T06:40:20+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-26T15:49:34+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-28T03:52:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"Sports Medicine-Open","date":"2025-07-26T03:08:59+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"sports-medicine-open","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"smoa","sideBox":"Learn more about [Sports Medicine-Open](http://sportsmedicine-open.springeropen.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/smoa/default.aspx","title":"Sports Medicine-Open","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"44f91b8f-b8c7-41fc-841f-1658d76b1315","owner":[],"postedDate":"September 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-21T14:42:12+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-03 23:56:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7182337","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7182337","identity":"rs-7182337","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}