Effects of exercise on bowel preparation before colonoscopy: a systematic review and meta-analysis of randomized controlled trials

Background: Before colonoscopy, bowel preparation is essential for adequate visualization, and the role of exercise in bowel preparation is worth exploring. We evaluated the impact of colonoscopy exercise on outcome bowel preparation in patients through a systematic review and meta-analysis. Methods: Cochrane Library, Embase, Web of Science, Pubmed, CNKI, and the Wanfang database were searched. Randomized controlled trials (RCTs) published from the establishment of the database to January 2024 were included. After screening the literatures, relevant data was extracted and evaluated for quality. The RevMan 5.3 software was used for meta-analysis. Results: A total of 8 studies (n = 1654) were included. The pooled results showed that the use of exercise intervention programs did significantly improve the quality of the patient’s bowel preparations [Mean Difference (MD) = 0.88, 95% Confidence Interval (CI): 0.55 to 1.20; p﹤0.00001] and the patient’s bowel preparation adequacy rate [Risk Ratio (RR) =2.85, 95% CI: 1.13 to 1.33; p＜0.0001]. However, there was no significant reduction in adverse events such as nausea, vomiting, abdominal pain, and bloating among individuals in the exercise intervention group, and satisfaction rate was not significantly improved. Conclusion: Exercise intervention can effectively improve the quality of bowel preparation before colonoscopy, and will not cause an increase in the incidence of adverse reactions, and will not reduce the patient ’s satisfaction with bowel preparation. Effects of exercise on bowel preparation before colonoscopy: a systematic review and meta-analysis of randomized controlled trials

Before colonoscopy, bowel preparation is essential for adequate visualization, and the role of exercise in bowel preparation is worth exploring. We evaluated the impact of colonoscopy exercise on outcome bowel preparation in patients through a systematic review and meta-analysis. Methods: Cochrane Library, Embase, Web of Science, Pubmed, CNKI, and the Wanfang database were searched. Randomized controlled trials (RCTs) published from the establishment of the database to January 2024 were included. After screening the literatures, relevant data was extracted and evaluated for quality. The RevMan 5.3 software was used for meta-analysis. Results: A total of 8 studies (n = 1654) were included. The pooled results showed that the use of exercise intervention programs did significantly improve the quality of the patient’s bowel preparations [Mean Difference (MD) = 0.88, 95% Confidence Interval (CI): 0.55 to 1.20; p﹤0.00001] and the patient’s bowel preparation adequacy rate [Risk Ratio (RR) =2.85, 95% CI: 1.13 to 1.33; p＜0.0001]. However, there was no significant reduction in adverse events such as nausea, vomiting, abdominal pain, and bloating among individuals in the exercise intervention group, and satisfaction rate was not significantly improved. Conclusion: Exercise intervention can effectively improve the quality of bowel preparation before colonoscopy, and will not cause an increase in the incidence of adverse reactions, and will not reduce the patient ’s satisfaction with bowel preparation.

Exercise; colonoscopy; bowel preparation; meta-analysis

Colonoscopy is one of the commonly used and effective methods for diagnosing and treating intestinal diseases. 1-3 The quality of intestinal preparation during colonoscopy plays a crucial role in the diagnosis and treatment of colonoscopy. Completion of the procedure and proper visualization of the intestinal mucosa are highly dependent on the quality of the bowel preparation. Insufficient preparation of the bowel may lead to a large amount of residual stool in the intestinal cavity which can obstruct the view through the colonoscope, leading to miss diagnosis of bowel tumors or precancerous lesions. Additionally, serious complications such as intestinal perforation and intestinal bleeding may occur. 4 However, studies have shown that approximately 20-40% of patients receiving a colonoscopy have poor bowel preparation. 5, 6 Bowel preparation is a relatively complicated procedure, and many factors may influence the quality, including proper diet restriction, patient compliance, use of split dose purgatives, and appropriate interval between the end of preparation and start of colonoscopy. 6-9 In addition, increasing studies have explored the exercise in bowel preparation before colonoscopy in recent years. 10 Because exercise can promote gastrointestinal emptying by enhancing gastrointestinal peristalsis, which can clean the gastrointestinal tract. However, the results were not consistent, it was still a disputable issue up to now. For example, Kim et al. 11 reported that the walking exercise was found to improve colonoscopic bowel cleansing. However, Gao et al. 12 observed that participants took 5,000-step walking exercise were not effective in routine pre-procedure cleanout for standard colonoscopy. Therefore, we aimed to perform a meta-analysis to determine the impact of exercise on bowel preparation.

This research was conducted according to the Cochrane Collaboration handbook 13 and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). 14 Furthermore, the meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under Registry#: CRD42023416485. Search strategy Two authors independently and systematically performed literature searches in PubMed, Cochrane Library, EMBASE, Web of Science, China National Knowledge Infrastructure (CNKI), and the Database of Chinese Ministry of Science & Technology (Wanfang) from the inception of the database to January 2024, the key search terms included “bowel preparation OR bowel cleansing OR colonoscopy” AND “exercise OR physical activity OR walking OR yoga OR exercise gymnastics OR abdominal vibration” AND “randomized OR randomised” . In addition, we also manually searched the reference list of published documents to prevent omissions.We have attached the specific retrieval strategy using the pubmed database as an example in Supplement 1. Inclusion and Exclusion Criteria The inclusion criteria for this meta-analysis were as follows: (1) patients aged 18 and above; (2) exercise for bowel preparation before colonoscopy; (3) detail outcomes were reported; (4) randomized clinical trials. The exclusion criteria were as follows: (1) review articles; (2) correspondences or editorial; and (3) conference abstract without detail data; (4) non-English or non-Chinese studies. For studies enrolled overlapping populations, we only included the study with the most comprehensive information and excluded the other. Data Extraction and Quality Assessment Two researchers independently screened the title, abstract, and full text of the articles based on the inclusion and exclusion criteria. Any discrepancies that occurred during the full text screening stage were resolved by consensus between the two reviewers. The characteristics of the included studies are presented in Table 1. A customized form was used to record the following data: the first author of the study, the year of publication, location of trial, age of subjects, study design, exercise, type bowel preparation solution and outcome indicators. The quality evaluation was performed by 2 reviewers. The methodological quality of the randomized controlled trials was assessed by modified Jadad score system. 15 Besides, we also used the Cochrane risk of bias tool 13 to evaluate the bias risk of included studies. Outcomes of interests The primary outcomes were the bowel preparation status, including the adequacy rate of bowel preparation and the scores of the bowel preparation scale. Adequate bowel preparation was defined as Boston bowel preparation scale (BBPS)≥2 scores for each segmental colon (right colon segment, transverse colon, and left colon segment) and ≥6 scores for all segments summation, Harefield Cleansing Scale scored A or B for all colon segments, Ottawa bowel preparation score was excellent (scored 0) or good (scored 1), or Aronchick Scale was excellent or good. The secondary outcomes were incidence of nausea, vomiting, abdominal bloating, abdominal pain, and satisfaction. Statistical Analysis Categorical variables are reported as frequencies and percentages, and continuous data are expressed as the mean ± standard deviation (SD). For continuous variables, the mean difference (MD) or standardized mean difference (SMD) with the 95% confidence interval (CI) was used when appropriate, depending on whether or not the outcomes were measured by the same scales, while the odds ratio (OR) with 95% CI was used for dichotomous variables (hair loss frequency). All statistical analyses were performed on Review Manager (RevMan version 5.3), with the significance level set to p < 0.1. Heterogeneity was measured using the I-square statistic, with a significance threshold of I²＞50%. 16 A random effect model was used if the I² statistic was significant, otherwise a fixed effect model was used. Literature Retrieval Results and Basic Characteristics Figure 1 showed the study selection flowchart. Through the literature search, we identified 645 citations. Using EndNoteX9 software for document management, we removed any duplicates and were left with 426 references. After excluding irrelevant reports by reviewing titles and abstracts, we then retrieved 28 full-text articles that were eligible. Ultimately, 8 original articles 11, 12, 17-22 were included, as shown in the study flowchart. Three of these studies 12, 17, 21 established three subgroups, which we considered to be two clinical trials. Study Characteristics Descriptive characteristics were shown in Table 1. Eight RCTs were included, 11, 12, 17-22 with a total sample size of 1694, including control (n = 703) and experimental (n = 951) participants. Four studies were published in Chinese, 19-21 the others were available in English. 11, 12, 17, 22 The sample sizes of the RCTs ranged from 40 to 131 participants. Seven included studies assessed qualification rate of bowel preparation (n = 7). Regarding adverse bowel preparation reactions, 3 studies measured nausea, 12, 21 vomiting 12, 21 and bloating. 20, 21 Four studies 12, 18, 20, 21 assessed abdominal pain. Quality Assessment The assessment of risk bias and literature quality evaluation for included studies were showed in Figure 2A, Figure 2B and Table 2. Five studies were scored as low quality, the remaining studies were judged as high quality. Primary outcomes Bowel cleanliness score Six studies assessed the quality of bowel cleansing. 11, 12, 17-22 The heterogeneity test I 2 = 79% showed that the included studies were heterogeneous and the random effects model was used for meta-analysis. We found that there was signiffcant difference in the bowel cleanliness score between the exercise intervention group and patients in the control group [Mean Difference (MD) = 0.88, 95% conffdence interval (CI): 0.55 to 1.20; p﹤0.00001;Figure 3]. Subgroup analysis We conducted subgroup analysis based on the study countries (Figure 3A) and PEG dosage(Figure 3B), which showed that grouping factors were not a significant factor affecting heterogeneity. Adequacy rate of bowel preparation All included studies reported the qualification rate of bowel preparation. 12, 17-19, 21 The studies were heterogeneous (I 2 = 60%) and the random effects model was used. We found the exercise intervention group could achieve comparable rate of adequate bowel preparation for whole colon when compared with control group [Risk Ratio (RR) =1.22, 95% CI: 1.13 to 1.33; p＜0.0001;Figure 4]. Subgroup analysis To identify the potential difference between the 2 groups, we performed subgroup meta-analysis according to countries (Figure 4A) and PEG dosage(Figure 4B), which showed that grouping factors were not a significant factor affecting heterogeneity. Secondary outcomes Data analysis of the incidence of adverse reactions Meta-analysis of adverse events data showed that the incidence of nausea [Risk Ratio (RR)=0.74, 95% CI: 0.45 to 1.22; p=0.24; I 2 = 38%], vomiting [Risk Ratio (RR)= 0.70, 95% CI: 0.17 to 2.91; p=0.62; I 2 = 66%], abdominal pain [Risk Ratio(RR)=0.93, 95% CI: 0.55 to 1.54; p=0.77; I 2 = 28%], and abdominal bloating [Risk Ratio (RR) =0.82, 95% CI: 0.54 to 1.23; p=0.33; I 2 = 49%] did not significantly decrease in the exercise interventions group. Most studies showed no heterogeneity. See as Table 3. Satisfaction rate Two studies reported the satisfaction rate. Because of no heterogeneity among these studies ( I 2 = 74%), a random effects model was used to pool result, which indicated that there were no significant differences in satisfaction rate [[Risk Ratio(RR)=1.02, 95% CI: 0.95 to 1.09 ; p=0.57 ; Figure 5] between the two groups. Due to the limited number of studies included, we did not conduct subgroup analysis to analyze the sources of heterogeneity. Publication bias The funnel plot was used to detect the publication bias of the adequacy rate of bowel preparation. Visual observations based on the funnel plot showed asymmetry, indicating that both may have publication bias ( Figure 6).

This systematic review and meta-analysis, including 8 RCTs and 1694, examined the impact of exercise interventions on bowel preparation for colonoscopy patients. Overall, exercise interventions improved improved the quality of intestinal preparation in patients underwent colonoscopy; but did not influence adverse events. Adequate bowel preparation was the guarantee for successful colonoscopy examination. At present, intestinal preparation is mainly dominated by cathartic drugs, but it was difficult to achieve good intestinal preparation effect with drugs alone. Some studies have focused on the impact of exercise on the quality of intestinal preparation and find that exercise can effectively improve the quality of intestinal preparation. But the results vary. The results of this meta-analysis showed that exercise intervention could effectively improve the quality of bowel preparation and shorten the first bowel movement time. This was consistent with the results of another meta-analysis. 10 Proper walking during the preparation of the intestine for taking polyethylene glycol electrolyte was considered a necessary procedure to accelerate excretion. The possible reason for this was that walking could accelerate intestinal peristalsis, reduce the reabsorption of water by the intestine, and make feces easier to excrete. 23 Kumar et al. 24 identified difficulty walking as a strong predictor of inadequate bowel by analyzing the patient’s functional activity status. Previous animal studies of changes in intestinal movement according to exercise showed that running increased the period of large intestinal contraction regardless of having a meal, generated giant migratory contractions just after exercise start, and promoted defecation by generating mass colon movement. 25 In addition, this meta-analysis found that increasing exercise during bowel preparation did not increase the incidence of adverse reactions, nor did it reduce patient satisfaction with bowel preparation. It is worth noting that the meta-analysis results of Huang et al. 10 showed that quantitative exercise intervention can effectively reduce the incidence of adverse reactions, which is different from our research results. At present, most patients use laxatives to promote intestinal cleansing prior to colonoscopy. 26 Although, reasonable exercise could promote blood circulation in the intestinal tract, stimulate the movement of the digestive tract, and accelerate the absorption and excretion of intestinal contents, and may reduce the adverse side effects such as abdominal pain and vomiting. 24 However, PEG taste was poor and the amount of liquid taken was also large, which maight be the main reason why some patients experienced adverse reactions such as nausea, vomiting, abdominal pain, bloating, and poor satisfaction during the intestinal preparation process. 27-29 Therefore, it was worth further exploring whether exercise can improve these situations. The limitations of this study were also existed. First, most included studies are RCTs with low quality. Second, the number of research articles and the sample sizes included were relatively small, the form and amount of exercise were not uniform, which maight reduce the reliability of this research results to a certain extent. Furthermore, some results had high heterogeneity. We thought this could be affected by several factors, including most studies from a single country and low quality literature. In conclusion, current research suggested that exercise could improve the quality of BP before colonoscopy and shorten the first bowel movement time, but it did not seem to reduce the occurrence of adverse events such as nausea and vomiting. In the future, multicenter, large sample, and well-designed randomized controlled studies should be needed to verify the impact of exercise intervention on the quality of intestinal preparation and adverse reactions. Acknowledgments We gratefully acknowledge all the study participants who made this study possible. Disclosure All authors have no potential conflicts of interest to disclose. Funding/Support No external funding.

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Figure Legends: Figure 1.Flowchart for search strategies Figure 2.Risk of bias summary1 Figure 2B.Risk of bias summary2 Figure 3.Forest plots of bowel cleanliness scores Figure 3A.Subgroup analysis of intestinal cleansing score by countries Figure 3B.Subgroup analysis of intestinal cleansing score by PEG dose Figure 4.Forest plots of adequacy rate of bowel preparation Figure 4A.Subgroup analysis of qualification rate of bowel preparation by countries Figure 4B.Subgroup analysis of qualification rate of bowel preparation by subgroups of PEG dosage Figure 5. Forest plots of satisfaction rate Figure 6. Funnel plot Tables Table 1 Characteristics of studies comparing different educational instructions for bowel preparation prior to colonoscopy Table 2 Quality assessment of studies included in meta-analysis based upon Jadad Scale Table 3 Data analysis of the incidence of adverse reactions Supplementary Material File (figure 1.flowchart for search strategies.doc) - Download - 23.56 KB File (table 1 characteristics of each included study.docx) - Download - 14.39 KB File (table 2 quality assessment of included studies.docx) - Download - 12.36 KB File (table 3 data analysis of the incidence of adverse reactions.docx) - Download - 11.71 KB Information & Authors Information Version history Copyright This work is licensed under a Non Exclusive No Reuse License.

Authors Metrics & Citations Metrics Article Usage 534views 139downloads Citations Download citation Gu Jie, Zhang Wen, Lu Jianying, et al. Effects of exercise on bowel preparation before colonoscopy: a systematic review and meta-analysis of randomized controlled trials. Authorea. 04 July 2025. DOI: https://doi.org/10.22541/au.175161613.31139159/v1 DOI: https://doi.org/10.22541/au.175161613.31139159/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu.