The effects of menstrual cycle phase on acute critical power testing performance in healthy females.

AIM

Critical power (CP) is derived from the hyperbolic relationship between power output and time to exhaustion (TTE) and delineates severe-intensity exercise from the heavy-intensity domain. Fluctuations in endogenous and exogenous female sex hormones may influence this power-duration relationship.

PURPOSE

This study examined CP and subjective fatigue between low-hormonal (LHP) and high-hormonal (HHP) phases of the menstrual cycle (MC) in eumenorrheic (EUM), intrauterine device (IUD), and oral contraceptive (OC) using females.

METHODS

Thirty-five participants (mean ± SD: age: 24.3 ± 6.1 yrs, weight: 65.2 ± 7.0 kg) completed a randomized crossover design. Performance outcomes (CP [W], anaerobic work capacity [W´; J], TTE [sec], and total work [J]) were evaluated from three TTE trials at 110%, 80%, and 95% of peak oxygen consumption. Subjective feelings of fatigue, sleepiness, consciousness, and energy were obtained from validated questionnaires.

RESULTS

CP (LHP-HHP; Δ ± SE: 0.81 ± 1.87 W), W´ (Δ -295.44 ± 415.04 J), TTE (Δ: 110%: -7.98 ± 6.16 s; 95%: 1.21 ± 9.44 s; 80%: - 52.63 ± 25.80 s), total work (Δ: - 8,022 ± 4,590 J), and energy (Δ: - 1.69 ± 8.45 a.u) were not significantly different between MC phases. Greater subjective fatigue (LHP-HHP; Δ: - 5.69 ± 12.08 a.u; p = 0.009), sleepiness (Δ: - 3.34 ± 9.70 a.u; p = 0.049), and consciousness (Δ: - 0.86 ± 2.1 a.u; p = 0.024) were identified in HHP.

CONCLUSION

These data suggest that MC phase does not alter parameters of the power-duration relationship in recreationally active females, but subjective feelings of fatigue may be altered during the high-hormone phase of the MC.