Resting and exercise ventilatory chemosensitivity across the menstrual cycle

Area of Science:

• Physiology
• Reproductive Endocrinology
• Respiratory Control

Background:

• Ventilatory chemosensitivity, the body's response to changes in oxygen and carbon dioxide levels, is influenced by hormones.
• Estrogen and progesterone levels fluctuate throughout the menstrual cycle, prompting investigation into their effects on respiratory control.

Purpose of the Study:

• To investigate the impact of menstrual cycle phase on resting and exercise ventilatory chemosensitivity in women.
• To compare ventilatory chemosensitivity and exercise responses between women across their menstrual cycle and with men.

Main Methods:

• Healthy women (n=10) were assessed across four menstrual cycle phases (early follicular, late follicular, early luteal, mid-luteal).
• Men (n=10) served as controls.
• Measurements included resting ventilation, hypoxic ventilatory response (iHVR), hypercapnic ventilatory response, and submaximal exercise in normoxia and hypoxia.

Main Results:

• Resting minute ventilation was higher in the mid-luteal phase compared to early and late follicular phases.
• Hypoxic chemosensitivity (iHVR) was unaffected by menstrual cycle phase and similar between sexes.
• Exercise ventilation and ventilatory responses to normoxic and hypoxic exercise were similar between sexes and unaffected by menstrual cycle phase.

Conclusions:

• Naturally occurring changes in estrogen and progesterone do not significantly alter ventilatory chemosensitivity in women.
• Hormonal influences on chemosensitivity are insufficient to overcome inherent physiological variability.
• Exercise-related physiological mechanisms appear to override hormonal effects on ventilation during physical activity.