Ergogenic effects of beetroot juice supplementation during severe-intensity exercise in obese adolescents

Previous studies showed a higher O2 cost of exercise, and therefore a reduced exercise tolerance, in obese patients during constant work rate (CWR) exercise compared to healthy subjects. Among the ergogenic effects of dietary nitrate (NO3-) supplementation in sedentary healthy subjects, a reduced O2 cost and enhanced exercise tolerance have often been demonstrated. The aim of this study was to evaluate the effects of beetroot juice supplementation, rich in NO3-, on physiological variables associated with exercise tolerance in obese adolescents. In a double-blind, randomized, crossover study, ten obese adolescents (8F, 2M; age=16{plus minus}1 yr; BMI=35.2{plus minus}5.0 kg.m-2) were tested after 6 days of supplementation with beetroot juice (5 mmol NO3- per day) (BR) or placebo (PLA). Following each supplementation period, patients carried out two repetitions of 6-min moderate-intensity CWR exercise and one severe-intensity CWR exercise until exhaustion. Plasma NO3- concentration was significantly higher i...