STUDY OBJECTIVE Obstructive sleep apnea (OSA) patients have a high frequency of arousals. We hypothesized that arousals significantly influence tonic sympathetic nervous system function. DESIGN We examined the association of 11 variables measuring sympathetic activity, including plasma norepinephrine (NE), urinary NE, and BP measurements, with movement and cortical arousals. PATIENTS Sixty-...

Disorders of fluid balance are common in the elderly and often are caused by age-related alterations in urinary tract function, which can present clinically as urinary frequency, nocturia, and incontinence. Among the factors predisposing to the development of these clinical disturbances are aging changes in the renal and hormonal systems that control water and sodium excretion along with change...

OBJECTIVE The objective of this study is to investigate the association between actigraphic estimates of the sleep-wake rhythm and a range of functional domains that contribute to well-being in demented elderly patients. METHOD Eighty-seven women aged 85.5 +/- 5.9 years (mean +/- standard deviation) wore an actigraph for two weeks. Activity profiles were analyzed using nonparametric variables...

The modest daytime hypertension and sympathetic upregulation associated with the sleep apnoea/hypopnoea syndrome (SAHS), does not explain the relatively large increased risk of cardiac morbidity and mortality in the SAHS patients population. Therefore, efferent vagal and sympathetic activity was evaluated during wakefulness in SAHS subjects and matched healthy controls, in order to determine if...

BACKGROUND Through adaptation, animals can function visually under an extremely broad range of light intensities. Light adaptation starts in the retina, through shifts in photoreceptor sensitivity and kinetics plus modulation of visual processing in retinal circuits. Although considerable research has been conducted on retinal adaptation in nocturnal species with rod-dominated retinas, such as ...

The siesta habit is associated with a 37% reduction in coronary mortality, possibly because of reduced cardiovascular stress associated with daytime sleep. Whether the most important behavior is the daytime nap itself, a supine posture, or the expectancy of a nap is unknown. We present the first detailed description on healthy individuals of the acute changes in cardiovascular function during d...