Ishijima, T., Hashimoto, H., Satou, K., Kanosue, K., Muraoka, I., Suzuki, Ki. & Higuchi, M. (2009). The effect of menstrual cycle on cardiovascular and subjective response during prolonged submaximal exercise in the heat. A paper presented at the 14th Annual Congress of the European College of Sport Science, Oslo, Norway, June 24-27.

"Women before menopausal are exposed physiological and psychological changes by hormonal variation during the menstrual phase. Although only a few studies with hormonal verification have investigated cardiovascular and subjective responses to submaximal exercise in the heat, no changes have been found over the menstrual cycle for these responses. As the cause of “no changes”, it should be pointed out the problem might be the exercise protocol (exercise intensity and duration)."

This study examined the effect of the menstrual cycle on cardiovascular and subjective responses during prolonged submaximal exercise in the heat for young adult women (N = 6) with regular menstrual cycles. Ss completed two trials consisting of 90 minutes cycling exercise at 50%VO2max in the heat (temperature ~30°; humidity; 50%) during the follicular phase (days 2-7) and luteal phase (days 18-24) of their menstrual cycles. Before and after exercise, blood sex hormone concentrations were measured. Ss did not ingest any fluid during the cycling exercise. During cycling exercise, ventilation, VO2, VCO2, respiratory rate, respiratory exchange ratio, heart rate, body core temperature, rating of perceived exertion-overall, rating of perceived exertion-cardiovascular, rating of perceived exertion-legs, blood glucose, and blood lactate were measured every 15 minutes.

Serum estradiol and progesterone concentrations were higher during the luteal phase when compared to the follicular phase. During cycling in the heat, body weight loss in the luteal trial was higher than in the follicular trial. During cycling exercise, VO2, heart rate, respiratory rate, and body core temperature were significantly increased in both trials. Although the respiratory exchange ratio during the luteal trial was higher than in the follicular trial during cycling exercise, no other cardiovascular parameter differed between the trials. All ratings of perceived exertion were significantly increased during cycling exercise in both trials. Rating of perceived exertion-overall and rating of perceived exertion-legs during the luteal trial were higher than in the follicular trial over the complete exercise.

Implication. Physiological and psychological strains increase during the luteal phase during prolonged submaximal exercise in hot conditions. Most cardiovascular indices do not change over the menstrual cycle. In the luteal phase, ratings of perceived exertion are higher than in the follicular phase.

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