EFFECTS OF THE MENSTRUAL CYCLE ON THE SWEATING RESPONSE OF WOMEN IN A HOT ENVIRONMENT

Abstract

Women exercising during the luteal phase of the menstrual cycle in a hot environment are exposed to additional heat sources. For instance, women are exposed to heat produced by the exercising muscles, heat gained from the environment, and heat from the elevated body temperature observed during the luteal phase of the menstrual cycle. PURPOSE The study was designed to investigate the effects of the menstrual cycle phase on the sweating response of female athletes exercising in a hot environment. METHODS Seven eumenorrheic female athletes performed a 60-min run on a treadmill at 60% peak oxygen consumption, wearing a vinyl sauna suit. The subjects were tested in both the mid-follicular (days 4–7 after flow onset) and the mid-luteal (days 19–22 after flow onset) phases of the menstrual cycle. Rectal temperature, mean body temperature, mean skin temperature, temperature inside the sauna suit, sweat rate, weight loss, plasma volume changes, heart rate, rating of perceived exertion, and respiratory exchange ratio were measured. A one-tailed repeated measures t-test was used to analyze differences between the two menstrual cycle phases. RESULTS Significantly higher mean (p < .05) rectal temperature, mean body temperature, mean skin temperature and heart rate were found during the luteal phase than the follicular phase of the menstrual cycle. No significant (p > .05) differences were found between phases relative to the rest of the variables measured. CONCLUSION The results indicate that thermoregulation and cardiovascular strain were affected by the menstrual cycle phase. More thermoregulatory stress and more cardiovascular strain were experienced during the luteal phase than the follicular phase. Supported by Dept. of Exercise Science, Springfield College.