Specifying the Cardio-Respiratory Patterns During Fast-Paced Breathing

Area of Science:

• Physiology
• Cardiovascular Science
• Respiratory Medicine

Background:

• Fast-paced breathing (FPB) is proposed to enhance physiological activation for motor-cognitive tasks.
• Limited empirical data exists on the specific cardiac changes induced by FPB.
• Understanding cardiac responses is crucial for optimizing FPB protocols.

Purpose of the Study:

• To systematically quantify changes in heart rate variability and cardiac contractility during FPB.
• To compare FPB at 35 and 55 cycles/min (CPM) against spontaneous and slower paced breathing.
• To assess the influence of breathing discomfort on cardiac responses.

Main Methods:

• Thirty-eight healthy, active participants underwent 2.5-minute breathing exercises at various frequencies (spontaneous, 6, 15, 35, 55 CPM).
• Electrocardiography and impedance cardiography monitored heart rate variability (RMSSD) and cardiac contractility (pre-ejection period).
• Breathing discomfort was self-reported.

Main Results:

• FPB at 35 and 55 CPM significantly reduced heart rate variability.
• Cardiac contractility increased significantly only at 55 CPM FPB.
• Breathing discomfort escalated with increasing deviation from spontaneous breathing rate.

Conclusions:

• Cardiac responses to FPB are frequency-dependent, with higher frequencies inducing more pronounced effects.
• FPB at 55 CPM demonstrates significant cardiac stimulation, impacting both variability and contractility.
• These findings contribute to understanding the physiological mechanisms underlying paced breathing techniques.