Heart rate variability and exercise in aging women

Area of Science:

• Exercise Physiology
• Cardiovascular Health
• Autonomic Nervous System Function

Background:

• Previous research indicated exercise training improves maximal cardiorespiratory exercise capacity (VO2max) and heart rate variability (HRV).
• However, no VO2max improvement was observed in women aged 60 years and older.
• This study investigates the HRV response to exercise in postmenopausal women stratified by age (younger and older than 60).

Purpose of the Study:

• To examine the heart rate variability (HRV) response to varying intensities of exercise training in postmenopausal women.
• To compare the HRV response between postmenopausal women younger than 60 years and those 60 years and older.
• To assess the impact of exercise on parasympathetic tone and its relationship with age.

Main Methods:

• 365 sedentary, overweight, hypertensive, postmenopausal women were randomized into a sedentary control group or exercise groups.
• Exercise groups trained at 50% (4 kcal/kg/week), 100% (8 kcal/kg/week), or 150% (12 kcal/kg/week) of NIH physical activity guidelines.
• Primary outcomes included time and frequency domain indices of heart rate variability (HRV).

Main Results:

• Significant improvements in parasympathetic tone (measured by rMSSD and high frequency power) were observed in both age groups at 8 and 12 kcal/kg/week.
• Specifically, rMSSD showed notable increases in women aged 60 and older at higher exercise intensities (8 and 12 KKW).
• While VO2max did not improve in older women, their HRV indices demonstrated a positive response to exercise training.

Conclusions:

• Exercise training, particularly at higher intensities, enhances parasympathetic indices of heart rate variability (HRV) in postmenopausal women, including those aged 60 and older.
• Despite no improvement in maximal cardiorespiratory exercise capacity (VO2max), the increase in HRV suggests potential cardiovascular benefits.
• Heart rate variability (HRV) serves as a crucial indicator of cardiovascular disease (CVD) risk and has neurovisceral implications independent of cardiorespiratory function.