Blegen, M., Cheatham, C. C., Caine-Bish, N., & Glickman, E. L. (2004). The thermoregulatory responses to exercise of varying intensities in normoxic and hypoxic environments. Medicine and Science in Sports and Exercise, 36(5), Supplement abstract 2310.

This study investigated the effects of hypoxia on the thermoregulatory responses during prolonged moderate and high intensity exercise. Males (N = 9) underwent two maximal aerobic capacity tests (VO2max) prior to the initiation of the experimental trials, one VO2max test under normoxic conditions, the other under mildly hypoxic conditions (inspired oxygen concentration = 14.65%). Ss exercised for 60 minutes under four randomly assigned experimental conditions that were separated by at least seven days: 1) 40% normoxic VO2max in a normoxic environment, 2) 40% hypoxic VO2max in a hypoxic environment, 3) 60% normoxic VO2max in a normoxic environment, and 4) 60% hypoxic VO2max in a hypoxic environment. Rectal temperature and mean skin temperature were measured at baseline, 5, 10, 20, 30, 40, 50, and 60 minutes of exercise.

A significant difference in rectal temperature was found between normoxic and hypoxic conditions, but not for skin temperature. As would be expected, temperatures were different between low and high intensity exercises.

Implication. Exercise in a hypoxic environment places a greater demand on the body's ability to thermoregulate than does exercise in a normoxic environment.

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