Comparison of Linear and Nonlinear HRV Dynamics Across Exercise Intensities After Menopause

Area of Science:

• Cardiovascular Physiology
• Exercise Science
• Autonomic Nervous System Function

Background:

• Heart rate variability (HRV) reflects autonomic nervous system balance.
• Understanding HRV dynamics during exercise is crucial for assessing cardiovascular health.
• Postmenopausal women may experience altered autonomic function with aging and exercise.

Purpose of the Study:

• To compare linear and nonlinear heart rate variability dynamics during rest, maximal exercise, and recovery.
• To investigate the effects of moderate versus high-intensity exercise training on HRV in postmenopausal women.
• To assess specific HRV indices including RR triangular index, TINN, SD1, SD2, SD1/SD2, DFA α1, DFA α2, and α1/α2.

Main Methods:

• Comparison of HRV parameters between moderate and high-intensity trained postmenopausal women.
• Measurement of HRV during rest, maximal exercise, and 2 minutes of active recovery.
• Analysis of linear (RR triangular index, TINN) and nonlinear (SD1, SD2, SD1/SD2, DFA α1, DFA α2, α1/α2) HRV indices.

Main Results:

• Maximal exercise significantly reduced most HRV indices (SD1, SD2, DFA α1, DFA α2, α1/α2, RRTri, TINN) and increased SD1/SD2 in both groups.
• Active recovery led to significant increases in SD1, SD2, DFA α1, and TINN compared to exercise levels.
• The moderate-intensity group exhibited higher RR triangular index levels during recovery compared to the high-intensity group.

Conclusions:

• Both moderate and high-intensity exercise training induce a healthy HRV response to maximal exercise and subsequent recovery in postmenopausal women.
• Moderate-intensity training may offer a slightly superior recovery profile for the RR triangular index.
• HRV analysis provides valuable insights into the autonomic adaptations to different exercise intensities in this population.