Influence of Menstrual Cycle Phase, Oral Contraceptive Use and Sex-Related Differences on Heat Tolerance while Wearing NBC Protective Clothing


  1. McLellan, T.M.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Canadian Forces personnel must be able to sustain operations in an environment contaminated with NBC agents. However, because of the thickness and low vapour permeability of the protective clothing ensemble, there is considerable heat strain associated with wearing full NBC protection in warm and hot environments. The report focuses on the problems of wearing the NBC clothing for women and how their responses compare with men. Due to oscillations in core temperature throughout the menstrual cycle, women who are non-users of oral contraceptives will show variations in heat tolerance when protective clothing is worn. Tolerance times will be the longest during the early follicular phase (days 2-5) of the cycle when starting core temperature is at its lowest value. Because of the increase in body temperature associated with ovulation, tolerance times will be reduced by about 10% during the luteal phase of the cycle. The use of oral contraceptives appears to eliminate these oscillations in heat tolerance. The proportion of body fat has a significant impact on the body's overall capacity to store heat. Those individuals, male or female, with a higher body fat content will have a reduced capacity to store heat and, therefore, a lower heat tolerance when protective clothing is worn. During light exercise, tolerance times for men while wearing NBC clothing exceeded those for women by 25%. TRUNCATED
Follicular phase;Luteal phase;Body fatness;Aerobic fitness
Report Number
DCIEM-97-R-50 —
Date of publication
01 Oct 1997
Number of Pages
Hardcopy;Document Image stored on Optical Disk

Permanent link

Document 1 of 1

Date modified: