Changes in Exhaled Carbon Dioxide during the Menstrual Cycle and Menopause

Area of Science:

• Metabolic physiology
• Women's health
• Endocrinology

Background:

• The menstrual cycle (MC) involves hormonal fluctuations impacting women's metabolism and physiology.
• Exhaled carbon dioxide (CO2) is a marker of metabolic fuel utilization.
• Understanding metabolic variations during the MC and menopause is crucial for women's health and fertility management.

Purpose of the Study:

• To investigate metabolic variations throughout the menstrual cycle using exhaled CO2 patterns measured by the Lumen device.
• To explore differences in CO2 levels in menopausal women with and without hormone replacement therapy (HRT).

Main Methods:

• A retrospective cohort study analyzed exhaled CO2 data from 3,981 Lumen users.
• Participants included eumenorrheic women and menopausal women with or without HRT.
• Linear mixed models were used to assess CO2 changes across MC phases and between menopausal groups.

Main Results:

• Eumenorrheic women exhibited cyclical CO2 patterns, with elevated levels during menstrual, estrogenic, and ovulation phases.
• CO2 levels decreased during post-ovulation and pre-menstrual phases, with consistent patterns despite cycle length variations.
• Menopausal women without HRT showed significantly different CO2 levels compared to those with HRT, who had lower levels.

Conclusions:

• Distinct CO2 patterns correlate with menstrual cycle phases, indicating hormonal influences on metabolism.
• Menopausal women's CO2 profiles are altered by the presence or absence of HRT.
• Exhaled CO2 monitoring may serve as a tool for tracking the MC and understanding menopausal metabolic changes.