Cardiorespiratory coupling strength in athletes and non-athletes

Area of Science:

• Cardiovascular Physiology
• Nonlinear Dynamics
• Autonomic Nervous System Function

Background:

• Heart period (HP) variability often exhibits nonlinearities due to cardiorespiratory coupling (CRC).
• Standard analysis of HP variability frequently omits concurrent respiratory movement (RESP) recordings.
• Understanding CRC is crucial for assessing cardiovascular regulation, especially during physiological challenges.

Purpose of the Study:

• To evaluate cardiovascular dynamics and CRC in athletes versus non-athletes during a postural challenge.
• To apply Joint Symbolic Analysis (JSA) for a deeper understanding of CRC.
• To investigate the influence of nonlinear components in HP variability.

Main Methods:

• A cross-sectional study involving 50 men (25 athletes, 25 non-athletes) aged 20-40.
• Recording of electrocardiogram, blood pressure, and RESP signals in supine (REST) and standing (STAND) positions.
• Computation of time/frequency domain indices, baroreflex sensitivity, and JSA based on symbolic HP and RESP patterns.

Main Results:

• JSA identified significantly higher CRC strength at REST in athletes.
• The response of CRC to the STAND maneuver was more pronounced in athletes, indicating greater autonomic reactivity.
• CRC response to postural change varied with analysis time scales, being more evident in athletes.

Conclusions:

• JSA offers superior insights into CRC compared to linear methods, especially for athletes.
• The nonlinear relationship between HP and RESP variability is better captured by JSA.
• Athletes demonstrate a more reactive autonomic control system, as evidenced by their CRC during postural challenges.