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Cardiovascular variability after arousal from sleep: time-varying spectral analysis
Anna Blasi1, Javier Jo, Edwin Valladares
1Biomedical Engineering Dept., OHE-500, Univ. Park, Los Angeles, CA 90089-1451, USA. khoo@bmsr.usc.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 24, 2003
Summary
Acoustic arousal during sleep causes lasting increases in blood pressure and heart rate variability, suggesting prolonged sympathetic nervous system activation. Parasympathetic activity changes are linked to breathing patterns.
Area of Science:
- Cardiovascular Physiology
- Sleep Science
- Autonomic Nervous System Regulation
Background:
- Heart rate variability (HRV) and blood pressure variability (BPV) reflect autonomic nervous system (ANS) function.
- Arousals from sleep significantly impact cardiovascular regulation.
- Understanding the temporal dynamics of cardiovascular responses to arousal is crucial for assessing autonomic function.
Purpose of the Study:
- To analyze time-varying spectral characteristics of HRV and BPV during acoustically induced arousals from sleep.
- To investigate the influence of respiration on HRV changes during arousal.
- To determine the duration of sympathoexcitatory cardiovascular effects following arousal.
Main Methods:
- Time-varying autoregressive modeling applied to HRV and BPV data from 16 healthy subjects during sleep arousals.
- Analysis of high-frequency (HF) and low-frequency (LF) power of HRV.
- Calculation of LF/HF ratio, systolic BPV LF power, and respiratory airflow HF power.
- Assessment of the transfer gain between respiration and heart rate.
Main Results:
- Cortical arousal led to rapid increases in muscle sympathetic nerve activity and heart rate, returning quickly to baseline.
- Systolic blood pressure, HRV LF/HF ratio, HRV LF power, and BPV LF power remained elevated for up to 40 seconds post-arousal.
- Concomitant decreases in HRV HF power and respiratory airflow HF power were observed, with unchanged respiratory-heart rate transfer gain.
Conclusions:
- Arousal-induced alterations in parasympathetic activity are closely associated with respiratory patterns.
- Sympathetic nervous system activation following arousal has prolonged cardiovascular effects that may accumulate with closely spaced, repetitive arousals.