Comparison of the Effectiveness of High-Intensity Interval Training in Hypoxia and Normoxia in Healthy Male Volunteers: A Pilot Study

Aims: The study investigated the effect of high-intensity interval training in hypoxia and normoxia on serum concentrations of proangiogenic factors, nitric oxide, and inflammatory responses in healthy male volunteers.

Methods: Twelve physically active male subjects completed a high-intensity interval training (HIIT) in normoxia (NorTr) and in normobaric hypoxia (HypTr) (FiO = 15.2%). The effects of HIIT in hypoxia and normoxia on maximal oxygen uptake, hypoxia-inducible factor-1-alpha, vascular endothelial growth factor, nitric oxide, and cytokines were analyzed.

Results: HIIT in hypoxia significantly increases maximal oxygen uptake (=0.01) levels compared to pretraining levels. Serum hypoxia-inducible factor-1 (=0.01) and nitric oxide levels (=0.05), vascular endothelial growth factor (=0.04), and transforming growth factor- (=0.01) levels were increased in response to exercise test after hypoxic training. There was no effect of training conditions for serum baseline angiogenic factors and cytokines ( > 0.05) with higher HIF-1 and NO levels after hypoxic training compared to normoxic training ( = 9.1; < 0.01 and  = 5.7; < 0.05, respectively).

Conclusions: High-intensity interval training in hypoxia seems to induce beneficial adaptations to exercise mediated via a significant increase in the serum concentrations of proangiogenic factors and serum nitric oxide levels compared to the same training regimen in normoxia.