Author(s): TAKITO, M., OLIVEIRA, T.N., SAUNDERS, B., DI BELLA, Z.J., KILPATRICK, M.W., ASANO, R.Y., HACKNEY, A.C., PRADO, R.C.R., Institution: SCHOOL OF PHYSICAL EDUCATION AND SPORT OF UNIVERSITY OF SAO PAULO, Country: BRAZIL, Abstract-ID: 913

INTRODUCTION:
The menstrual cycle is a complex and cyclic process in the female reproductive system, characterized by hormonal fluctuations, which has been understudied. Despite growing interest in this topic, findings remain inconsistent, especially regarding how different phases of the menstrual cycle affect maximal exercise capacity and psychophysiological responses in physically active women (1,2). As such, this study evaluated the exercise capacity and psychophysiological responses to a progressive cycling test throughout the menstrual cycle in women.

METHODS:
Nineteen physically active and eumenorrheic women (24±4 yrs, V̇O2peak=38.4±3.1 mL.kg-1.min-1) completed five graded exercise tests; three of those were performed at specific phases of the menstrual cycle (i.e., menses, follicular, and luteal). Samples of blood, menstrual distress, mood, and anxiety were collected before and after each test. Affect, exertion, heart rate, and motivation were collected before, during, and after exercise. One-way ANOVA for repeated measures compared the exercise capacity between the menstrual cycle phases (i.e., menses, follicular, and luteal) and a two-way ANOVA to compare the differences between menstrual cycle phases and exercise moment. A simple linear regression was conducted to examine whether the level of menstrual cramps could significantly predict exercise capacity during the menses phase. Statistical significance was set at p < 0.05.

RESULTS:
Progesterone increased in response to the exercise, and an interaction effect indicated that estrogen responses to exercise varied depending on the phase. The menstrual cycle phase did not significantly impact exercise capacity. However, Wpeak and time to exhaustion were impaired during the menses phase among women who reported high levels of menstrual cramps (p<0.05). Higher affective valence scores were associated with improved outcomes (time to exhaustion: +8.5 s; Wpeak: +4.2 W; p = 0.02; R2 = 0.36), whereas higher arousal scores were associated with reduced exercise capacity (time to exhaustion: -6.4 s; Wpeak: -11.4 W; p = 0.01; R2 = 0.46) between the menstrual cycle. Motivation was lower during menses compared with the follicular phase (p = 0.04).

CONCLUSION:
These findings suggest that although the menstrual cycle phase does not uniformly affect maximal exercise capacity, individual symptoms, such as menstrual cramps, may play a critical role. Future studies are encouraged to explore both physiological and psychological responses further to exercise across the menstrual cycle, with particular attention to symptom variability and female-specific experiences.

[1] Prado et al. (2021). Physiol Behav, 232, 113290
[2] Prado et al. (2022). Int J Sports Physiol Perform, 18(2) 142–14.


Funding: CNPq [403633/2021-4], CAPES [Finance Code 001 and #88887.716790/2022-00], and FAPESP [2021/06836-0 and 2022/07327-4].