Resistance Exercise in a Hot Environment Alters Serum Markers in Untrained Males

International audiencePurposeWe examined the effects of moderate resistance exercise (RE) on serum cortisol, testosterone, extracellular heat shock protein (HSP70), and interleukin (IL)-6 and IL-15 concentrations in untrained males in a hot environment. MethodsTen untrained young males (26 +/- 3 years; 75.8 +/- 6 kg; 177.4 +/- 5.3 cm) performed two series of full body RE [3 sets of 8 to 10 repetitions, 30-60 s recovery between series with 70% of one maximal repetition (1-RM), with a rest period of 1 to 3 min between exercises] carried out in a random order in both heated (similar to 35 degrees C) and thermoneutral (22 degrees C) conditions. Serum concentrations of testosterone, cortisol, HSP70, and IL-6 and IL-15 were measured before, at the end, and 1 h after RE sessions. Participants in both groups consumed 4 ml of water/kg body mass every 15 min. ResultsThere were time-related changes in testosterone, HSP70, and IL-6 (P< 0.001), and cortisol and IL-15 (P< 0.05). Levels of cortisol, HSP70, and IL-6 increased immediately for RE at 35 degrees C, and testosterone and IL-15 levels were decreased. Changes in serum testosterone, HSP70, cortisol, and IL-15 and IL-6 levels were reversed after 1 h. A significant time x condition interaction was observed for IL-15 and HSP70 (P< 0.001), cortisol and IL-6 (P< 0.05), but not for testosterone (P> 0.05). ConclusionRE in a heated environment may not be appropriate for achieving muscle adaptations due to acute changes of hormonal and inflammatory markers