Stress responsivity in exercisers and non-exercisers during different phases of the menstrual cycle.

It has been suggested that, premenstrually, women are more vulnerable to the effects of stress. It has also been proposed that the fitter the individual is, the less the body responds to, and the more quickly it recovers from, a stressful experience. The present study investigated whether premenstrual sensitivity to a stressful laboratory task would be attenuated in women who exercised. Responses to the task across the menstrual cycle were studied in 20 women who exercised regularly and 20 women who were sedentary. Heart rate and blood pressure as well as subjective mood responses were measured in each of three phases: premenstrual, menstrual and postmenstrual. Exercising and sedentary women differed in sensitivity to stress: heart rate responsivity to stress was less in exercisers, but mood fluctuation was greater. Menstrual cycle phase, by contrast, influenced general levels of heart-rate and mood, but did not affect responsivity to stress or performance. These findings suggest that the menstrual cycle and physical exercise have independent effects on cardiovascular and emotional state.