Menstrual cycle,exercise and stress response

ABSTRACT Menstrual Cycle, Exercise and Stress Response Aim: Aim of this thesis was to assess the interactions between exercise (shortand long-term) and phases of the menstrual cycles on the activity of stress axes (hipothalamo-pituitary-adrenal: HPA and autonomous nervous system: ANS). Material and Method: In Experiment I, women undertaking physical- or mental-based education were filled questionnaires (n=340) about their menstrual cycles. In Experiments II and III, healthy and young (18-22 year-old) sportswomen (n=29) or sedentary women (n=28) were investigated at menstruation phase, follicular phase, periovulatory stage, luteal phase and premenstrual phase for the activity of their stress axes (HPA and ANS) in response to low- or high-effort exercise (10 min jogging, 100 m sprint, respectively). Salivary cortisol, heart rate variability (HRV) and salivary alpha-amylase were measured. In Experiment IV, diurnal cortisol and alpha-amylase were assessed in the same women during menstruation. In Experiment V, tendency of women towards physical or mental activities were assessed at menstruation phases. Results: Menstruation was longer and BMI was higher in women undertaking mental-based education (P<0.05). Sportswomen had higher HRV (p<0.05) and exercise decreased HRV but increased alpha-amylase (P<0.05). Menstrual phases did not affect stress axes (P>0.05). Diurnal secretion of cortisol was higher in sportswomen (P<0.05) and pain was higher during menstruation and premenstrual phases. Conclusion: In conclusion, (1) long-term exercise was associated with improved ANS, better BMI index, less menstrual bleeding, (2) among the parameters studied HRV best reflected the changes caused by exercise, (3) menstrual phases did not affect stress axes, and thus they can be studied in women at any phase. Key Words: Menstruation, Exercise, HRV, Cortisol, Alpha-amylase