The Influence of Menstrual Cycle Phase and Cramp Severity on Psychological Responses and Exercise Capacity in Physically Active Eumenorrheic Women.

Introduction: The scientific literature is characterized by a historical underrepresentation of the female population in sports science. A critical issue in the current literature is the inconsistency between objectively measured (e.g., time to exhaustion) and subjectively perceived performance across the menstrual cycle. This inconsistency is often attributed to methodological limitations (e.g., absence of hormonal assessments and ovulation kits) and to the lack of consideration of menstrual-related symptoms and psychological variables.

Purpose: The primary

Objective: of the study was to compare graded exercise test (GXT) performance outcomes across menstrual cycle phases. A secondary

objective was to investigate whether cramp severity was associated with GXT performance during menses. A final

objective was to investigate whether cramp severity was associated with GXT performance during menses. A final objective was to examine the effects of menstrual cycle phase on psychological responses to exercise.

Methods: Nineteen physically active eumenorrheic women (age 24 ± 4 years, V̇O2peak 38.4 ± 3.1 mL·kg -1·min -1) completed five GXTs: two for familiarization and three performed during experimental sessions scheduled in three specific phases of the menstrual cycle (menses, follicular, and luteal). Variables of interest included estradiol and progesterone levels, affective valence, arousal, anxiety, heart rate, rating of perceived exertion, mood disturbance, and motivation. Exercise capacity was operationalized as GXT performance outcomes (peak power output [Wpeak] and time to exhaustion). Cramp severity was measured only during menses.

Results: No statistically significant differences in Wpeak or time to exhaustion were detected across menstrual cycle phases (p > 0.05). Secondary and exploratory regression analyses indicated that each one-point increase in menstrual cramp severity during menses was associated with lower GXT performance (Wpeak: -1.50 W; time to exhaustion: 2.72 s; p = 0.04; R 2 = ~0.35). Higher affective valence scores were associated with improved Wpeak (+4.27 W) and time to exhaustion (-8.51 s; p = 0.02; R 2 = ~0.36), whereas higher arousal scores were associated with lower Wpeak (-11.40 W) and higher time to exhaustion (6.47 s; p = 0.01; R 2 = ~0.46) across the menstrual cycle. Motivation was lower during menses than during the follicular phase (p = 0.04).

Conclusions: No statistically significant differences in GXT performance were detected across menstrual cycle phases. However, secondary and exploratory analyses suggest that greater menstrual cramp severity during menses was associated with lower time to exhaustion and Wpeak. These

Findings: provide preliminary evidence that menstrual-related symptoms and psychological factors may contribute to variability in GXT performance outcomes and warrant further investigation in larger cohorts.