Cardiorespiratory transfer during sleep: a study in healthy young men

Area of Science:

• Cardiorespiratory Physiology
• Sleep Science
• Autonomic Nervous System Regulation

Background:

• Respiratory influences on cardiovascular variability are significant during wakefulness.
• Understanding these cardiorespiratory interactions during sleep is crucial for assessing autonomic function.
• Previous research has not fully elucidated the role of breathing pattern modifications in sleep-related cardiovascular variability.

Purpose of the Study:

• To investigate the extent to which changes in breathing parameters account for respiratory-related blood pressure (BP) and R-R interval (RRI) variability during nocturnal sleep.
• To determine the relationship between specific breathing pattern modifications and cardiorespiratory transfer characteristics across different sleep stages.
• To assess the contribution of respiratory modulation of vagal activity to BP and RRI variability during sleep.

Main Methods:

• Continuous polygraphic recordings were obtained from 13 healthy young men, including BP (Finapres), electrocardiogram, and respiration (Respitrace).
• Transfer characteristics (coherence and gain) between thoraco-abdominal motion and respiratory-related BP/RRI variability were analyzed.
• Statistical analyses correlated changes in breathing parameters (respiratory rate, tidal volume, ribcage-to-abdominal motion ratio) with sleep stage transitions.

Main Results:

• Cardiorespiratory transfer characteristics significantly increased from wake to light sleep and light to deep sleep, returning to waking levels during rapid-eye-movement (REM) sleep (P < 0.0001).
• These changes were significantly associated with modifications in respiratory rate, tidal volume, and the ribcage-to-abdominal motion ratio across sleep stages (0.28 < r < 0.39; P < 0.0001).
• Breathing pattern modifications accounted for 8-15% of the variance in cardiorespiratory transfer during sleep.

Conclusions:

• Changes in breathing patterns are a significant factor influencing cardiorespiratory transfer variability during sleep.
• Respiratory modulation of vagal activity is not the primary mechanism driving the magnitude of respiratory-related BP and RRI variability during sleep.
• The findings highlight the importance of considering breathing pattern dynamics in the interpretation of cardiorespiratory control during sleep.