Sleep
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It is now well acknowledged that napping constitutes an inherent component of the human circadian system. To date, however, few studies have examined the effects of spontaneous napping on human free-running rhythms. This study investigated the free-running circadian periods of rest/activity and body core temperature in a group of young subjects who were permitted to nap during their time in isolation. ⋯ Nappers exhibited free-running rhythms in both rest/activity and body core temperature that were not significantly different from 24 hours. Nappers showed a tendency for shorter free-running periods in both variables, when compared with Nonnappers. These findings emphasize the need for careful reassessment of data obtained from traditional free-run protocols.
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Comparative Study
Effect of nasal continuous positive airway pressure during sleep on 24-hour blood pressure in obstructive sleep apnea.
Ambulatory blood pressure (BP) was measured noninvasively (Oxford Medilog ABP) at 15-minute intervals for 24 hours before and after 8 weeks of treatment with nasal continuous positive airway pressure (nCPAP) in 19 men with obstructive sleep apnea (OSA). We included both normotensive and hypertensive patients, but hypertensives were studied after withdrawal of antihypertensive drugs. Ambulatory BP before and after treatment was compared using patients as their own controls. ⋯ The mean blood pressure fell in both normotensive and hypertensive patients. Patients who were inadequately treated with nCPAP had no reduction in mean 24-hour BP. Effective treatment of sleep apnea with nCPAP was associated with a significant fall in both systolic and diastolic BP independent of changes in body weight or alcohol consumption, suggesting that sleep apnea was an independent factor contributing to elevated nighttime and daytime BP in these patients.
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We investigated the way in which nasal continuous positive airway pressure (CPAP) affects the circadian profiles of blood pressure (BP) and heart rate (HR) in obstructive sleep apnea syndrome (OSAS) patients. Nine patients with OSAS, confirmed by nocturnal polysomnography, were studied with ambulatory blood pressure monitoring (Colin ABPM-630) during two 48-hour periods, before and during nasal CPAP treatment, at the Stanford University Sleep Disorders Clinic. During each 48-hour monitoring period, blood pressure measurements were taken by the ambulatory device every 30 minutes. ⋯ Average BP (systolic/diastolic) and HR during the 48-hour periods decreased significantly from 148.6/88.2 mm Hg to 138.7/81.4 mm Hg, and from 77.9 beats per minute (bpm) to 67.2 bpm in hypertensives during CPAP treatment (p = 0.04), but there were no significant changes observed in normotensives. Average BP, during the day and at night, decreased from 152.3/91.8 mm Hg to 141.2/85.1 mm Hg and from 133.9/76.8 mm Hg to 125.9/73.7 mm Hg, respectively, in the hypertensives during CPAP, but such changes were not observed in normotensives. Average HR during the day and at night decreased significantly from 85.2 bpm to 72.6 bpm and from 69.8 bpm to 56.5 bpm in the hypertensives (p = 0.04), but not in normotensives.(ABSTRACT TRUNCATED AT 250 WORDS)
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Past studies have predicted that early morning awakening insomnia is associated with advanced or early circadian rhythms. Because bright light stimulation in the evening can delay the phase of circadian rhythms, we tested its effects on nine (4 females, 5 males) early morning awakening insomniacs. Their sleep was evaluated with wrist actigraphy and their temperature and melatonin circadian rhythms were measured in constant routine procedures. ⋯ Following the evening bright light treatment, temperature rhythm phase markers were delayed 2-4 hours and melatonin phase markers were delayed 1-2 hours. Sleep onset times were not changed but the mean final wake-up time was delayed from 0459 hours to 0611 hours, resulting in a mean increase of total sleep time of > 1 hour. This pilot study suggests that evening bright light stimulation may be an effective nondrug treatment for early morning awakening insomnia.
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Randomized Controlled Trial Clinical Trial
Successful treatment of the idiopathic restless legs syndrome in a randomized double-blind trial of oxycodone versus placebo.
In a double-blind randomized crossover trial, oxycodone or placebo was given in divided night-time doses to 11 patients with idiopathic restless legs syndrome (RLS) for 2 weeks prior to appropriate polysomnographic studies. Under double-blinded conditions, patients were asked to do daily ratings of their leg sensations, motor restlessness and daytime alertness on a 1-4 scale for the 2 weeks prior to the polysomnographic studies and for the nights of the polysomnographic studies as well. Leg sensations (p < 0.009), motor restlessness (p < 0.006) and daytime alertness (p < 0.03) were significantly improved on oxycodone as compared to baseline or placebo. ⋯ On an average dose of 15.9 mg oxycodone (equivalent to approximately three 5-mg tablets of commercial preparation), there was a statistically significant reduction in the number of periodic limb movements in sleep [(PLMS)/hour sleep (p < 0.004)] and in the number of arousals/hour sleep (p < 0.009) on drugs as compared to baseline or placebo. A statistically significant improvement was also noted in sleep efficiency (p < 0.006) and 10 of the 11 patients preferred oxycodone over placebo. We conclude that oxycodone is an effective treatment for RLS and PLMS.