Effects of Acute Exposure to Mild Simulated Hypoxia on Hormonal Responses to Low-intensity Resistance Exercise in Untrained Men

Abstract

This study examined hormonal responses to low-intensity resistance exercise under mild simulated hypoxia. Ten resistance untrained men performed five sets of 15 repetitions of squat exercise at 30% of 1RM under normobaric hypoxia (FiO₂ = 15%) and normoxia in a cross-over and counter-balanced design. Blood lactate (LAC), growth hormone (GH), total testosterone (T) and cortisol (C) were measured at pre-exercise, immediately post-exercise and 15 minutes post-exercise. LAC, GH and T significantly increased immediately after squat exercise in both trials (p < 0.05). While T returned to baseline, GH remained significantly greater at 15 minutes post-exercise. Cortisol significantly decreased immediately after and 15 minutes post-exercise in both trials (p < 0.05). No significant differences were observed between two trials in LAC, GH, T and C. It was concluded that low-intensity resistance exercise performed under mild simulated hypoxia does not induce greater anabolic hormonal responses in resistance untrained men.

KEYWORDS:

• anabolic hormones
• intermittent hypoxic training
• weight training

This study was funded by the National Science Council in Taiwan (Grant No. NSC100-2410-H-003-002) and partially supported by a grant for ‘Aim for the Top University Plan’ from National Taiwan Normal University and the Ministry of Education of Taiwan.