Influence of menstrual cycle phase and oral contraceptive use during compensable and uncompensable heat strain
Year: 1997
Type: dissertation
Abstract: The purpose of this study was to determine the influence of menstrual cycle phase and oral contraceptive use during compensable and uncompensable heat strain. Eighteen women (18-35 yr), who differed only with respect to oral contraceptive use (n = 9) or non-use (n = 9), performed light intermittent exercise at 40$\sp\circ$C, 30% relative humidity while wearing either Canadian Forces combat clothing or NBC protective clothing. Thermoregulatory responses in each clothing configuration were compared during the early follicular (EF, days 2-5), late follicular (LF, days 9-12), and mid luteal (ML, days 19-22) phases of the menstrual cycle. Rectal temperature was elevated in ML compared with EF among the non-users, but not the users in both clothing configurations. There were no phase-related or group-related differences in any of the other indices of heat strain. Tolerance times were similar between the two groups in all three phases during the compensable heat strain trials. During uncompensable heat strain, tolerance times were significantly longer during EF (128.1 $\pm$ 13.4 min) compared with ML (107.4 $\pm$ 8.6 min) for the non-users, indicating that these women are at a thermoregulatory advantage during the EF phase of their menstrual cycle. For the users, tolerance times were similar in all three phases and did not differ from those of the non-users during uncompensable heat strain. Our results demonstrate that oral contraceptive use appears to make the thermoregulatory responses to heat strain more uniform over the course of the menstrual cycle.
Author: Sandra A. Tenaglia
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2789320274