How Significant Is Magnesium In Thermoregulation?

Nine apparently healthy male subjects, mean age 22.8 yr, SD 4.1, free from disease, medication or addiction who gave informed consent, underwent acclimation process in a heat chamber; exposed during 2 h daily for 10 consecutive days to a temperature of 40°C and 40% relative humidity while walking on a treadmill elevated by 3 at a speed of 5 km/h (VO₂1.2 l-min^-1). Serum, mononuclear and erythrocyte magnesium (S-Mg, M-Mg and E-Mg, respectively) were monitored on day 1, 5 and 10 before and after the heat exposure. S-Mg decreased while M-Mg increased after the heat exposures, suggesting a shift of S-Mg to mononuclear cells. The decrease of S-Mg was sustained at the end of the acclimation process. E-Mg increased up to day 5 and decreased gradually approximating the baseline by day 10. Mg appears to play a significant role in heat acclimation.