Relationship between change in core temperature and change in cortisol and TNFα during exercise

• Published in: Journal of thermal biology 2010-10, Vol.35 (7), p.348-353
• Main Authors: Hosick, Peter A., Berry, Mark P., McMurray, Robert G., Cooper, Erica S., Hackney, A.C.
• Format: Article
• Language: English
• Subjects: Environmental stress; Heat exposure; Hormones; Immersion
• ISSN: 0306-4565; 1879-0992
• DOI: 10.1016/j.jtherbio.2010.07.003

The combined thermal load created by exercise and a hot environment is associated with an exaggerated core temperature response. The elevated core temperature is believed to increase the total stress of the exercise. Increased stress during exercise has been associated with increased levels of cortisol. The association of cortisol with increased inflammatory responses following exercise in the heat is equivocal. Thus, the purpose of the current investigation was to explore the relationship between increases in rectal temperature ( T re) and TNFα and cortisol. To induce T re changes, 8 male subjects (mean±SD, age=23.6±2 yr, VO 2max=52.8±3.7 mL/kg/min, BMI=24.2±1.9) participated in two 40 min trials of cycle ergometry at 65% of VO 2peak immersed to chest level in cool (25 °C) and warm (38.5 °C) water. T re was monitored throughout each trial, with blood samples taken immediately pre and post of each trial. Neither cortisol nor TNFα changed significantly during exercise in the cool water; however, in the warm trial, both cortisol and TNFα significantly increased ( p