Sex differences in heat shock protein 72 expression in peripheral blood mononuclear cells to acute exercise in the heat.
BACKGROUND
Heat shock protein 72 (Hsp72) is responsible for maintaining critical cellular function during heat stress. Hsp72 confers thermotolerance and may play a role in heat acclimation. Animal research suggests a difference between sexes in Hsp72 expression in response to exercise, however, human data is lacking.


OBJECTIVE
To determine sex differences in intracellular heat shock protein 72 (Hsp72) following exercise in the heat.


METHODS
Nine non-heat acclimated women with normal menstrual cycles (VO2pk 58 ± 5 mL.kgFFM(-1).min(-1)) and nine non-heat acclimated men (VO2pk 60 ± 7 ml.kgFFM(-1).min(-1)) completed 2 treadmill bouts at 60% VO2pk for 60 min in a 42°C, 20% RH environment. Women were tested in follicular (fol) and luteal (lut) phases. The duplicate trials were separated by 12 days for men and women. Blood samples were drawn pre, immediately post, 1, and 4 hrs post-exercise.


RESULTS
Men and women differed in their Hsp72 response after exercise (time X sex X trial interaction; P < 0.05). Men increased Hsp72 after exercise more than women. Both men and women produced less Hsp72 during trial 2 compared to trial 1. Estrogen (r = 0.24; P > 0.05) and progesterone (r = 0.27, P > 0.05) concentrations were not correlated with Hsp72.


CONCLUSIONS
Our findings suggest that men and women differ in their cellular stress response. Men up-regulated Hsp72 after a single bout of exercise in the heat, which persists for 12 days, suggesting an accumulation of Hsp72 which may lead to acquired cellular thermotolerance.
Department of Kinesiology, California Baptist University, Riverside, USA.
Trevor
T
Gillum
Department of Sports and Exercise Science, West Texas A&M University, Canyon, USA.
Matthew
M
Kuennen
Department of Health, Exercise and Sport Sciences, The University of New Mexico, Albuquerque, USA.
Cheryl
C
Gourley
Department of Internal Medicine, The University of New Mexico, Albuquerque, USA.
Karol
K
Dokladny
Department of Health, Exercise and Sport Sciences, The University of New Mexico, Albuquerque, USA.
Suzanne
S
Schneider
Department of Internal Medicine, The University of New Mexico, Albuquerque, USA.
Pope
P
Moseley
Endogenous antioxidants; Menstrual Phase; Thermoregulation; Thermotolerance