Effects of Aerobic Exercise in Different Environments on Body Weight and Body Fat Mass of Obese and Overweight Adolescents

Objective:Aimed to explore the effects of aerobic exercise in altitude or stimulated hypoxia on body weight and body fat mass of obese and overweight adolescents.Methods:50 healthy overweight or obese adolescents aged 16to 22years old, living in plain, without cardio-vascular diseases, no bad habits such as smoking and drinking, no systematic training history, took part in this research.They were divided into plain training group (plain group, PG) , hypoxic training group (living high-training high-training low group, 2300m, HG) and altitude training group (Qinghai Duoba training base, ≈2300m, AG) .The intervention last for four weeks.The plain group live and exercise in Shanghai, exercise six days per week.Hypoxia group sleep in simulated 2300mnomobaric hypoxia from 19:00to 07:00, training 2hours at this hypoxia environment in daytime, other arrangements is the same as the plain group.Altitude group exercise and live in Qinghai Duoba training base every day.Daily exercise volume was 5hours for three groups.Restricted diet, 2500kcal intake for male and 2100kcal intake for female, based on resting metabolic rate to ensure the basic energy demand.We monitored heart rate every ten minutes in the process of movement to ensure the intensity was in the target range.Target heart rate intensity was 40% of the heart rate reserve, which determined by the Karvonen equation.During the four-weeks intervention, we tested the body weight every fast morning.Body fat mass was measured by dual energy X-ray absorption.Results: (1) Compared with pre-intervention, body weight was significantly reduced after four weeks in three intervention methods (P<0.05) .Weight loss amplitude showed both HG and PG were obviously higher than AG (10.18%、9.34% vs 7.56%, P<0.05) .No significant difference was founded between HG and PG. (2) During four-weeks intervention, it showed that weight loss amplitude of HG and PG was gradually decreased, which was biggest in the first week and notable higher than the forth week.But the biggest weight loss amplitude of AG arise in the second week.It founded that weight loss amplitude in 1st week of HG and PG was significant higher than AG (3.58%、3.39% vs 2.31%, P<0.05) .Weight loss amplitude in 2nd week of HG was obviously higher than PG (3.03% vs 2.36%, P<0.05) .Until 3rd week, HG was remarkable higher than PG and AG (2.65% vs 2.10%、1.92%, P<0.05) .No significant difference existed in the 4th week. (3) Total FM loss to body weight loss showed as AG >HG>CG (86.84%, 60.47%, 58.52%) and the difference between AG and HG or PG were significant (86.84% vs 60.47%、58.52%, P<0.05) .But no remarkable difference existed between PG and HG. (4) Fat mass (FM) of arm, leg, trunk and whole body took a significant loss after intervention (P<0.05) .FM change percent showed trunk>leg>arm. Total FM loss of AG and HG were little bigger than PG, but no outstanding difference.Trunk FM change percent were AG:18.13%, HG:15.98% and CG:14.08% and there was a notable trend between AG and CG (P=0.08) .FM loss range of arm and leg in these groups were bigger, but no marked difference among them.Conclusions:Four-weeks aerobic endurance training in plain, hypoxia and altitude could reduce body weight, total body fat mass and fat mass in different region of overweight and obese adolescents effectively.Fat mass loss of trunk took over most part of total reduced fat mass.From the amount and amplitude of weight reduction point, exercise and living in altitude didn't show any more effect than plain and hypoxic training.However, it suggested that altitude training was helpful to decrease the fat mass, especially helpful to reduce the trunk fat.