No effect of supplemented heat stress during an acute endurance exercise session in hypoxia on hepcidin regulation.

Abstract

The purpose of the present study was to compare endurance exercise-induced hepcidin elevation among "normoxia", "hypoxia" and "combined heat and hypoxia". Twelve males (21.5 ± 0.3years, 168.1 ± 1.2cm, 63.6 ± 2.0kg) participated in the present study. They performed 60min of cycling at 60% of [Formula: see text] in either "heat and hypoxia" (HHYP; FiO2 14.5%, 32°C), "hypoxia" (HYP; FiO2 14.5%, 23°C) or "normoxia" (NOR; FiO2 20.9%, 23°C). After completing the exercise, participants remained in the prescribed conditions for 3h post-exercise. Blood samples were collected before, immediately and 3h after exercise. Plasma IL-6 level significantly increased immediately after exercise (P < 0.05), with no significant difference among the trials. A significant elevation in serum EPO was observed 3h after exercise in hypoxic trials (HHYP and HYP, P < 0.05), with no significant difference between HHYP and HYP. Serum hepcidin level increased 3h after exercise in all trials (NOR, before 18.3 ± 3.9 and post180 31.2 ± 6.3ng/mL; HYP, before 13.5 ± 2.5 and post180 23.3 ± 3.6ng/mL, HHYP; before 15.8 ± 3.3 and post180 31.4 ± 5.3ng/mL, P < 0.05). However, there was no significant difference among the trials during post-exercise. Endurance exercise in "combined heat and hypoxia" did not exacerbate exercise-induced hepcidin elevation compared with the same exercise in "hypoxia" or "normoxia".