Cardiovascular variability after arousal from sleep: time-varying spectral analysis

• Published in: Journal of applied physiology (1985) Vol. 95; no. 4; pp. 1394 - 1404
• Main Authors: Blasi, Anna, Jo, Javier, Valladares, Edwin, Morgan, Barbara J, Skatrud, James B, Khoo, Michael C. K
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.10.2003; American Physiological Society
• Subjects: Adult; Arousal - physiology; Biological and medical sciences; Blood pressure; Blood Pressure - physiology; Cardiovascular Physiological Phenomena; Fundamental and applied biological sciences. Psychology; Heart; Heart Rate - physiology; Humans; Middle Aged; Models, Biological; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Parasympathetic Nervous System - physiology; Pulmonary Ventilation - physiology; Respiratory system; Sleep; Sleep - physiology; Sympathetic Nervous System - physiology; Time Factors; Vertebrates: nervous system and sense organs; Human; Cardiovascular control; Variability; Sleep disorder; physiological oscillations; Spectral analysis; Heart rate; blood pressure variability; Sleep; sleep-disordered breathing; Autonomic nervous system; heart rate variability; Arousal; mathematical modeling; Blood pressure; Sleep wake cycle; Mathematical model
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01095.2002

1 Biomedical Engineering Department, University of Southern California, Los Angeles, California 90089; and 2 Departments of Medicine, and Orthopedics & Rehabilitation, University of Wisconsin, Madison, Wisconsin Submitted 2 December 2002 ; accepted in final form 13 June 2003 We performed time-varying spectral analyses of heart rate variability (HRV) and blood pressure variability (BPV) recorded from 16 normal humans during acoustically induced arousals from sleep. Time-varying autoregressive modeling was employed to estimate the time courses of high-frequency HRV power, low-frequency HRV power, the ratio between low-frequency and high-frequency HRV power, and low-frequency power of systolic BPV. To delineate the influence of respiration on HRV, we also computed respiratory airflow high-frequency power, the modified ratio of low-frequency to high-frequency HRV power, and the average transfer gain between respiration and heart rate. During cortical arousal, muscle sympathetic nerve activity and heart rate increased and returned rapidly to baseline, but systolic blood pressure, the ratio between low-frequency and high-frequency HRV power, low-frequency HRV power, the modified ratio of low-frequency to high-frequency HRV power, and low-frequency power of systolic BPV displayed increases that remained above baseline up to 40 s after arousal. High-frequency HRV power and airflow high-frequency power showed concommitant decreases to levels below baseline, whereas the average transfer gain between respiration and heart rate remained unchanged. These findings suggest that 1 ) arousal-induced changes in parasympathetic activity are strongly coupled to respiratory pattern and 2 ) the sympathoexcitatory cardiovascular effects of arousal are relatively long lasting and may accumulate if repetitive arousals occur in close succession. autonomic nervous system; heart rate variability; blood pressure variability; sleep-disordered breathing; mathematical modeling; physiological oscillations Address for reprint requests and other correspondence: M. C. K. Khoo, Biomedical Engineering Dept., OHE-500, Univ. Park, Los Angeles, CA 90089-1451 (E-mail: khoo{at}bmsr.usc.edu ).