Influence of daily-life activation on pulse rate and blood pressure changes during the menstrual cycle

The aim of the present study was to evaluate the influence of endogenous cyclic changes in female sex hormones during the complete normal menstrual cycle on the daily-life activation of blood pressure and pulse rate. Sixteen normotensive women were investigated daily in the morning during strict bed rest and in the evening after normal daily activities throughout two complete menstrual cycles. Analysis of variance revealed a significant change in morning temperature during the menstrual cycle (P < 0.001), with a raise after midcycle. There was no significant variation in body weight during the cycle. Resting pulse rate increased by 1.7 beats/min from follicular (days 2-8) to luteal (days 20-26) phase in morning recordings (P < 0.01) and by 2.9 beats/min in evening recordings (P < 0.001). Pulse pressure was 2.7 mmHg and systolic blood pressure 3.9 mmHg higher in the evening compared with the morning readings (P < 0.05 for both) in the luteal phase, but were similar in the follicular phase. The influence of daily-life activation on pulse rate and systolic blood pressure, defined as the difference between morning and evening levels, was significantly greater in the luteal phase compared with the follicular phase (delta 1.3 beats/min, P < 0.05 and delta 3.0 mmHg, P < 0.05, respectively). In the present study we find evidence of an altered response in haemodynamic recordings to environmental stress during the menstrual cycle. This interpretation is supported by previous findings of increased responses to experimental stress and extends these observations to naturally occurring stress in daily-life.