Effect of exercise in a warm environment on circulating neutrophils

The primary purpose of this investigation was to determine if exercise in the heat elicited a greater increase in the number of circulating neutrophils than exercise in a cool environment. The secondary purposes were to, 1) investigate the relationship between the change in core temperature (T(re)) and the degree of neutrophilia and 2) validate a previously stated hypothesis that T(re) must increase to greater than 38°C to elicit a significant rise in neutrophilia. Cycling for 40 minutes at 65% VO(2)peak caused neutrophilia, which was most evident two hours post-exercise. Moreover, exposure to the heat during exercise resulted in higher core temperatures and elicited a greater neutrophilia two hours post-exercise. No relationship was observed between a T(re) of 38°C and increases in the circulating neutrophil count. However, a T(re) of 38°C appears to contribute to exercise-induced neutrophilia since a greater exercise-induced T(re) occurred concomitantly with greater neutrophilia