The menstrual cycle and exercise‐induced cutaneous blood flow

Abstract

The study purpose was to determine if menstrual cycle (mc) phase impacts the cutaneous vascular response to exercise in young women. Thirteen healthy women ages 20‐28 yrs were studied (mean 23.3 years). None of the women were taking oral contraceptives and all reported having had regular menstrual cycles for the past year. The exercise consisted of 20 min of brisk treadmill walking at a room temp of 32 C and 45% relative humidity. Skin blood flow (SBF) at the forearm and back was recorded before and throughout the exercise. A dual‐channel laser Doppler flowmeter was used to measure SBFs, and the values were stored in computer and later analyzed by commercial software. Using ANOVA mean SBFs for both skin locations were compared before and at 2 min intervals during exercise. One set of SBFs was taken at the mid‐follicular phase (F) of the mc. Another set was recorded at the mid‐luteal phase (L). The order in which the mc phases were studied was randomized. The vascular responses at the two phases were then compared to determine if mc phase altered the thermoregulatory response. Results showed vasodilation at each skin location during both mc phases. When the two phases were compared, it was found that the response was most pronounced during the L phase (12% greater SBF at forearm, P = 0.08; 23% greater SBF at back, P = 0.03). The different vascular responses to exercise are likely accounted for by the different hormonal conditions present.