IMPORTANCE All studies of 24-hour intraocular pressure (IOP) rhythm conducted to date have used repeated IOP measurements requiring nocturnal awakenings, potentially disturbing sleep macrostructure. OBJECTIVE To evaluate the effects on sleep architecture and IOP rhythm of hourly awakening vs a contact lens sensor (CLS) to continuously monitor IOP without awakening. DESIGN, SETTING, AND PART...

Why do we go to sleep late and struggle to wake up on time? Historically, light-dark cycles were dictated by the solar day, but now humans can extend light exposure by switching on artificial lights. We use a mathematical model incorporating effects of light, circadian rhythmicity and sleep homeostasis to provide a quantitative theoretical framework to understand effects of modern patterns of l...

The effects of immediate-release melatonin on circadian rest-activity profiles, cognition, and mood were investigated in ten elderly individuals with self-reported sleep-wake disturbances. Melatonin (6 mg), administered 2 hr before habitual bedtime, enhanced the rest-activity rhythm and improved sleep quality as observed in a reduction in sleep onset latency and in the number of transitions fro...

Repeated stressor exposure can sensitize physiological responses to novel stressors and facilitate the development of stress-related psychiatric disorders including anxiety. Disruptions in diurnal rhythms of sleep-wake behavior accompany stress-related psychiatric disorders and could contribute to their development. Complex stressors that include fear-eliciting stimuli can be a component of rep...

Recent epidemiological and clinical studies indicate that the control of sleep-wake states may be an important factor in the regulation of energy metabolism. Leptin is a peripherally synthesized hormone that has critical signaling properties in the brain for the control of long-term energy homeostasis. In this study, we examined the hypothesis that leptin signaling exerts a role in sleep-wake r...

BACKGROUND Cranial radiation therapy (CRT) is required for successful treatment of a variety of brain tumours in childhood. OBJECTIVE To investigate whether childhood CRT leads to altered sleep-wakefulness organization in adulthood, and to identify the determinants of such alterations. SUBJECTS AND METHODS Subjective (questionnaires) and objective (actigraphy) measures of circadian rhythmic...

Circadian rhythm sleep disorders are common in clinical practice. The disorders covered in this review are delayed sleep phase disorder, advanced sleep phase disorder, free-running, irregular sleep-wake rhythm, jet lag disorder and shift work disorder. Bright light treatment and exogenous melatonin administration are considered to be the treatments of choice for these circadian rhythm sleep dis...

To determine the relationships among plasma ghrelin and leptin concentrations and hypothalamic ghrelin contents, and sleep, cortical brain temperature (Tcrt), and feeding, we determined these parameters in rats in three experimental conditions: in free-feeding rats with normal diurnal rhythms, in rats with feeding restricted to the 12-h light period (RF), and in rats subjected to 5-h of sleep d...

Circadian disruption in shift-work is common and has deleterious effects on health and performance. Current efforts to mitigate these harms reasonably focus on the phase of the circadian pacemaker, which unfortunately in humans, shifts slowly and often incompletely. Temporal reorganization of rhythmic waveform (i.e., the shape of its 24 h oscillation), rather than phase, however, may better mat...

While circulating levels of PTH follow a diurnal pattern, it has been unclear whether these changes are truly endogenous or are dictated by external factors that themselves follow a diurnal pattern, such as sleep-wake cycles, light-dark cycles, meals, or posture. We evaluated the diurnal rhythm of PTH in 11 normal healthy male volunteers in our Intensive Physiologic Monitoring Unit. The first 3...