Heart rate and its variability change after the menopause

Area of Science:

• Cardiovascular Physiology
• Menopause Research
• Autonomic Nervous System Function

Background:

• Hormonal changes during menopause can impact cardiovascular health.
• Resting heart rate and heart rate variability are key indicators of cardiovascular function and autonomic nervous system activity.
• Previous research has indicated potential alterations in these parameters post-menopause.

Purpose of the Study:

• To compare resting heart rate and heart rate variability between premenopausal and postmenopausal women.
• To investigate the timeline of cardiovascular changes in relation to the last menstrual period (LMP).
• To assess the influence of menopause on autonomic nervous system function, independent of hormone replacement therapy.

Main Methods:

• Electrocardiograph (ECG) records were used to measure heart rate (mean R-R interval) and heart rate variability (standard deviation of R-R intervals).
• Participants included 33 postmenopausal women (LMP >= 1 year prior) and 50 premenopausal women.
• Activity levels were standardized using a modified Allied Dunbar National Fitness Survey scale.

Main Results:

• Postmenopausal women, particularly those >= 1 year past LMP, showed a significant reduction in mean R-R interval (slower heart rate).
• A significant decrease in heart rate variability (reduced standard deviation of R-R intervals) was observed in postmenopausal women (>= 1 year past LMP).
• No significant changes in heart rate or heart rate variability were detected within the first year post-menopause.

Conclusions:

• Menopause, particularly beyond the first year, is associated with significant reductions in resting heart rate and heart rate variability.
• These findings suggest a decline in autonomic nervous system function following menopause.
• The cardiovascular effects of menopause on heart rate regulation become evident more than one year after the final menstrual period.