Influences of Normobaric Hypoxia Training on Apelin Serum Levels and Insulin Resistance in Healthy Overweight Men

Considering the apelin effects on glucose metabolism, insulin, and its changes in hypoxia condition conditions, this study aimed to investigate the effect endurance training in normobaric hypoxia on apelin and insulin resistance in overweight men. Twenty healthy overweight men (Mean±SD; Age, 23.1±6.7; BMI, 28.2±1.9) that voluntarily participated in this study were randomly divided in to two hypoxia and normoxia groups. The eight-week training of the hypoxia group was performed at a simulated altitude of 2,700 meters in a hypoxia tent with an intensity of 60% of maximum oxygen consumption and normoxia group training was performed in normal conditions. Blood sampling was done in two groups, before and after 48 hours after the last training session, and used for measuring apelin and insulin and glucose levels. Mixed ANOVA test was used for comparing all variable at a significant level of P≤0.05. The results of comparing all variables changes in both training conditions showed that 8 weeks of training in hypoxic conditions did not affect body composition and VOmax indices compared to exercise in normal conditions (P>0.05), but significantly increased Apelin and significantly decreased insulin resistance and Insulin compared with the normoxia group (P<0.05). This study showed for the first time that eight weeks of training in normobaric hypoxia conditions caused an increase in the apelin serum level in overweight men, and training in hypoxic conditions compared to exercise in normal conditions, cause further decrease of insulin resistance.