Autonomic function responses to training: Correlation with body composition changes

•Exercise training improves vagal activity, body composition and aerobic fitness.•Vagal activity changes are associated with fat reduction after aerobic exercise.•Correlations are observed between changes of vagal activity and aerobic fitness.•Resting heart rate variability changes may predict adaptations to training program.

AimThe causal relation between autonomic function and adiposity is an unresolved issue. Thus, we studied whether resting heart rate variability (HRV) changes could be used to predict changes in body composition after 16 weeks of individualized exercise training.MethodsA total of 117 sedentary overweight/obese adults volunteered to join an intervention group (IN, n = 82) or a control group (CON, n = 35). The intervention group trained for 30-40 min three times a week with an intensity of 85-100% of individual ventilatory threshold (Thvent). At baseline and after a 16-week training period, resting HRV variables, body composition and peak oxygen uptake (VO2peak) were assessed.ResultsCompared with CON, exercise training significantly improved HRV and body composition and increased VO2peak (P < 0.05). Significant correlations were observed between changes of HRV variables and body composition indices and VO2peak (P < 0.05). Greater individual changes in HRV in response to exercise training were observed for those with greater total and central fat loss.ConclusionIndividual aerobic-based exercise training was for improving autonomic function and resting HRV responses to aerobic training is a potential indicator for adaptations to exercise training.