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While there is a developing understanding of the influence of sleep on cardiovascular autonomic activity in humans, there remain unresolved issues. In particular, the effect of time within the sleep period, independent of sleep stage, has not been investigated. Further, the influence of sleep on central sympathetic nervous system (SNS) activity is uncertain(More)
Existing literature on reward motivation pays scant attention to the fact that reward potential of the environment varies dramatically with the light/dark cycle. Evolution, by contrast, treats this fact very seriously: In all species, the circadian system is adapted to optimize the daily rhythm of environmental engagement. We used 3 standard protocols to(More)
Arousals from sleep can be associated with increases in blood pressure (BP). However, it is uncertain whether this is due to a direct effect of arousals on BP, or is secondary to respiratory stimuli present at the time of the arousal. Cheyne-Stokes respiration (CSR) in patients with congestive heart failure (CHF) provides unique conditions that may allow(More)
At the onset of non-rapid-eye-movement (NREM) sleep there is a fall in ventilation and an increase in upper airway resistance (UAR). In healthy men there is a progressive increase in UAR as NREM sleep deepens. This study compared the pattern of change in UAR and ventilation in 14 men and 14 women (aged 18-25 yr) both during sleep onset and over the NREM(More)
Heart rate (HR), blood pressure (BP) and autonomic nervous system (ANS) activity vary diurnally, with a reduction in HR and BP, and a shift to vagal dominance during the dark phase. However, the cause of these changes, particularly the relative influence of sleep and circadian mechanisms, remains uncertain. The present study assessed the effect of sleep(More)
STUDY OBJECTIVES The intent of the study was to explore the nature and function of the cardiovascular activation response that occurs at an arousal from sleep. DESIGN Four experiments were conducted. The first compared the pattern of physiologic response to orienting and startle stimuli and arousal from sleep. The second and third measured the amplitude(More)
Previous work has shown that the magnitude of state-related ventilatory fluctuations is amplified over the sleep-onset period and that this amplification is partly due to peripheral chemoreceptor activity, because it is reduced by hyperoxia (J. Dunai, M. Wilkinson, and J. Trinder. J. Appl. Physiol. 81: 2235-2243, 1996). These data also indicated(More)
Arousal from sleep is associated with elevated cardiac and respiratory activity. It is unclear whether this occurs because of homeostatic mechanisms or a reflex activation response associated with arousal. Cardiorespiratory activity was measured during spontaneous arousals from sleep in subjects breathing passively on a ventilator. Under such conditions,(More)
Alterations in a number of measures of cardiac activity were examined during sleep onset in 6 participants over 3 experimental nights. Each sleep onset was divided into four consecutive phases: wakefulness, mixed alpha and theta activity, stage 2 NREM sleep with arousals, and stable stage 2 sleep. The variables measured were heart rate (HR), respiratory(More)
In studies of elderly individuals, ventilation and EEG-defined arousal have been shown to vary periodically and synchronously. Such results have been interpreted as indicating the primacy of sleep/wake state in causing ventilatory instability during sleep onset. However, because the elderly individuals studied were periodic breathers, the results do not(More)