Involvement of birth weight and body composition on autonomic recovery following aerobic exercise in children: A prospective, observational and analytical study

ABSTRACT Birth weight (BW) can be used to assess the health status of the newborn. However, its impacts on later in life regarding heart rate (HR) variability (HRV) is not totally clear. We aimed to analyze the involvement of BW and body composition on HRV recovery following aerobic exercise in children. The study was conducted in healthy children 9 to 11 years of age (40 females and 27 males) divided into two groups: G1 (BW 3400 grams, N = 34). The volunteers completed an experimental protocol of submaximal aerobic exercise on a treadmill and remained seated for 30 minutes after exercise. Systolic (SAP) and diastolic arterial pressure (DAP), respiratory rate (f) and HRV were analyzed before and during recovery from exercise. SAP and f were significantly decreased 30 minutes after exercise compared to 1 minute after exercise in G1 and G2. Mean HR, high frequency band of spectral analysis (HF), root mean square of successive interbeat intervals difference, SD1 index and mean lenght were diminished 0 to 5 minutes after exercise compared to rest in G2 while maximum lenght increased 0 to 5 minutes after exercise compared to resting in G2. Linear regression revealed association of fat percentage and BW with nonlinear HRV recovery. In conclusion, autonomic recovery after exercise was somewhat delayed in children with high BW. BW and fat percentage slightly influence HRV recovery.