Study of cardiovascular reactivity to mental stress in different phases of menstrual cycle.

Background: It is a well known fact that normally female sex hormone levels fluctuate during the menstrual cycle. The presence of receptors for these hormones on both heart and blood vessels may also hint at variations in physiological functions during menstrual cycle. So this study was an attempt to determine whether the follicular and luteal phases of menstrual cycle are characterized by variations in cardiovascular parameters in the resting state and also examine changes in cardiovascular reactivity to mental stress challenge during both the phases of menstrual cycle. Methodology: Thirty healthy females in the age group of 18-25 years with regular menstrual cycles fulfilling the inclusion criteria were examined for cardiovascular parameters (heart rate and blood pressures) at rest and their reactivity to mental stress during the follicular and luteal phase and were compared by using paired t-test. A p-value of <0.05 was considered as statistically significant. Results: The women included in the study produced the well known reactivity to mental stress, in terms of blood pressure and heart rate increases, but the two phases of menstrual cycle were indistinguishable in so far as reactivity patterns were considered. The resting values of these cardiovascular parameters were also alike during the two phases. Conclusion: We were unable to unearth any differences in resting and reactivity values of cardiovascular parameters during the course of a normal menstrual cycle. This shows that stress reactivity variations during different phases of menstrual cycle may not be due to variations in hormonal levels per se, but due to collusion of hormonal variations and unknown genetic influences.