The effect of the menstrual cycle on postexercise hypotension

Factors associated with the normal menstrual cycle affect cardiovascular regulation. For example, estrogen favors vasodilation which may be antagonized by progesterone. Currently, the effect of the menstrual cycle on postexercise hypotension is unknown. We hypothesized that, due to enhanced vasodilation in the ovulatory phase, postexercise hypotension and leg vasodilation would be augmented during the ovulatory phase. We studied eleven women (24.6 ± 4.5 yr) during the early follicular, ovulatory and mid‐luteal phases. Arterial blood pressure (auscultation) and femoral blood flow (Doppler ultrasound) were measured before and after 60 min of cycling at 60% of VO2peak. Femoral vascular conductance was calculated as flow/pressure. Prior to exercise, there were no differences in mean arterial pressure or femoral vascular conductance (both P > 0.379) across menstrual phases. At 60 min postexercise, mean arterial pressure was reduced from preexercise across all menstrual phases (P < 0.001 vs. preexercise); however, the decrease was not different across menstrual phases (P = 0.798) (early follicular; 2.3 ± 0.5 mmHg; ovulatory; 2.7 ± 0.4 mmHg; mid‐luteal; 3.6 ± 0.5 mmHg). At 60 min postexercise, femoral vascular conductance was elevated from preexercise across all menstrual phases (P < 0.001 vs. preexercise); however, the increase was not different across menstrual phases (P = 0.161) (early follicular; Δ66.9 ±20.5 %; ovulatory; Δ41.7 ±17.5 %; mid‐luteal; Δ 61.1 ± 12.8 %). In contrast to our hypothesis, postexercise hypotension and leg vasodilation were not altered by factors associated with the normal menstrual cycle. Supported by AHA grant 555623Z.