Effects of aerobic exercise training on variability and heart rate kinetic during submaximal exercise after gastric bypass surgery – a randomized controlled trial

Background: This study aimed to determine whether morbidly obese women have an alteration of heart rate (HR) kinetics and HR variability (HRV) during the 6-min walk test (6MWT) and if an aerobic exercise training can modify these indexes after gastric bypass surgery (GBS). Design and methods: Nineteen morbidly obese women were randomized to a trained (TG) or control group and 12 women of eutrophic group (EG) were also evaluated. The obese women were tested on two occasions: 1 week before and 4 months after GBS through record of HR and R-R intervals during 6MWT for analysis HR kinetics. The TG underwent an aerobic exercise training program on a treadmill (1-h session, totaling 36 sessions over 12-week). Results: Both obese groups demonstrated a significant reduction of rMSSD and slower HR kinetics during the 6MWT when compared to the EG. In addition, only the TG demonstrated a significant improvement in HRV indexes, walking distance, faster time constant and mean response time of HR during 6MWT after training (p < 0.05). Conclusion: Morbidly obese women have slower HR kinetics and altered cardiac modulation during submaximal exercise. However, aerobic exercise training can produce beneficial adaptations in HRV and faster HR kinetics following GBS.Implications for RehabilitationThe obesity is one of the most important threats to health in developed countries and bariatric surgery is an option for treatment of morbid obesity.Exercise is an effective means of improving health after this procedure due alterations of autonomic nervous system in this population.This study showed that a program of aerobic physical training after bariatric surgery was able to improve the kinetics of heart rate and the cardiac autonomic modulation, both evaluated during submaximal exercise.