Menstrual Cycle Phases Influence on Cardiorespiratory Response to Exercise in Endurance-Trained Females

Area of Science:

• Exercise Physiology
• Reproductive Endocrinology

Background:

• Sex hormone fluctuations across the menstrual cycle can influence physiological responses to exercise.
• Understanding these impacts is crucial for optimizing training and performance in female athletes.

Purpose of the Study:

• To analyze the impact of menstrual cycle phase on cardiorespiratory responses during high-intensity interval exercise (HIIE).
• To determine if hormonal changes affect physiological markers during intense exercise in endurance-trained females.

Main Methods:

• Twenty-one endurance-trained females completed HIIE in early-follicular, late-follicular, and mid-luteal phases.
• Menstrual cycle phases were verified using calendar, LH, and serum hormone analysis.
• Cardiorespiratory variables (e.g., ventilation, heart rate, oxygen consumption) were measured during exercise.

Main Results:

• Menstrual cycle phase significantly impacted ventilatory and heart rate responses to HIIE.
• Oxygen consumption, CO2 production, RER, breathing frequency, energy expenditure, and perceived exertion remained unaltered.
• Most measured cardiorespiratory variables were unaffected by menstrual cycle phase during HIIE.

Conclusions:

• Sex hormone fluctuations during the menstrual cycle do not significantly disrupt cardiorespiratory adjustments to HIIE in endurance athletes.
• While most physiological responses are stable, heart rate response shows variability.
• Training programs should consider the menstrual cycle phase, particularly for heart rate-based training adjustments.