Cortisol, high sensitivity C-reactive protein and ferritin adaptation to endurance training in naturally menstruating females vs. females using hormonal contraceptives

Abstract

Introduction: Ferritin, hs-CRP and cortisol are markers of iron metabolism, inflammation and stress, respectively. The current longitudinal study investigated the effect of eight weeks of moderate-intensity aerobic exercise on cortisol, high-sensitivity C-reactive protein (hs-CRP), and ferritin among naturally menstruating females and hormonal contraceptive users.

Methods: Thirty-two healthy young female volunteers were assigned to two experimental groups: the control group (n=13) (CON) (naturally menstruating females) and the hormonal contraceptive users (HC) group (n=19). Each group engaged in 1-3 workouts (running or brisk walking) per week for eight weeks, with each session lasting between 30-90 minutes. The training program involved maintaining a heart rate within the range of 60-75% of the maximum heart rate. Blood samples were collected in the early follicular phase and hormonal contraceptive active pill phase before and after eight weeks. Both groups follow the same training program with equal intensity and volume. The menstrual cycle (MC) phases were determined from the first day of bleeding. Clearblue advanced digital ovulation (CB-OT) kits were used for ovulation detection.

Results: No significant changes in cortisol and ferritin concentrations were reported after 8 weeks in either group, and the relative changes in cortisol and ferritin were not significant between groups (p>0.05). Cortisol showed a statistically significant difference between groups at both baseline and post-MIET, with the HC group demonstrating higher concentrations. A significant within-group difference was observed in hs-CRP for both groups. The CON group experienced a reduction, while the HC group saw an increase post-MIET, and there was a significant difference in the relative change in hs-CRP between the groups (p < 0.05).No significant relationship was reported between cortisol, hs-CRP, or between cortisol and ferritin (p>0.05)