Differences in Heart Rate Variability and Baroreflex Sensitivity between Male and Female Athletes

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Regulation
• Exercise Physiology

Background:

• Heart rate variability (HRV), blood pressure variability (BPV), and spontaneous baroreflex sensitivity (BRS) are key indicators of autonomic cardiovascular control.
• Previous research indicates sex-based differences in HRV and BRS, but not specifically in athletes.
• This study investigates sex differences in autonomic regulation markers among athletes.

Purpose of the Study:

• To compare autonomic regulation markers (BPV, HRV, BRS) between male and female athletes.
• To assess the influence of a controlled slow breathing protocol on these markers in athletes of both sexes.

Main Methods:

• 100 male and 65 female athletes underwent baseline pre-season assessment.
• Resting beat-to-beat blood pressure and R-R intervals were recorded using photoplethysmography and ECG.
• A 5-minute slow breathing protocol (6 breaths/min) was administered, followed by spectral and linear analysis, including BRS calculation.

Main Results:

• Male athletes exhibited significantly lower mean heart rate, RR interval SD2/SD1, and HRV % low-frequency power compared to females.
• Male athletes also showed higher blood pressure high-frequency power during controlled respiration.
• No significant differences were observed in any spontaneous baroreflex sensitivity parameters between male and female athletes.

Conclusions:

• Heart rate variability and blood pressure variability responses to slow breathing differ between male and female athletes.
• Spontaneous baroreflex sensitivity responses to slow breathing do not differ between male and female athletes.
• These findings highlight sex-specific autonomic adaptations in athletes.