Recent studies have demonstrated that the free cortisol response to awakening can serve as a useful index of hypothalamus-pituitary-adrenal axis (HPA) activity. This endocrine marker is rather consistent, shows good intraindividual stability across time and appears to be able to uncover subtle changes in HPA regulation. The present twin study investigated genetic factors as sources of the inter...

The objective of this study was to evaluate whether long-term shift work is associated with both the total hormonal secretion after awakening and the pattern of the cortisol levels during the first hour following awakening, among 65 randomly selected police officers who represent a high stress occupation. Dominant shift (Day, Afternoon, or Midnight) was ascertained using daily payroll records o...

Cortisol concentration in both serum and saliva sharply increases and reaches a peak within the first hour after waking in the morning. This phenomenon is known as the cortisol awakening response (CAR) and is used as an index of hypothalamus-pituitary-adrenal (HPA) axis function. We examined whether ovarian steroid concentrations increased after awakening as with the CAR in the HPA axis. To do ...

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...

BEING ASLEEP AT THE TIME OF RESIDUAL FIRE IS AN IMPORTANT RISK FACTOR FOR FIRE-RELATED DEATH.1 CONVENTIONAL RESIDENTIAL SMOKE ALARMS generally produce a tone of 85 dB, which will awaken most sleeping adults.2,3 However, studies of auditory arousal thresholds during sleep have shown that a much higher average stimulus intensity is required to elicit arousals in children than in adults, and that ...

Previous genetic investigations of variation in normal sleep have focused on measures that describe sleep over longer periods of time. We undertook a study with the aim of evaluating whether heritability can be found in single-night sleep traits. A classical twin study design of monozygotic and dizygotic twins, enriched with siblings of twins was employed. The study included adult twin pairs an...

Sleep disturbance induced by night-time noise is a serious environmental problem that can cause adverse health effects, such as hypertension and ischemic heart disease. Night-time noise indices are used to facilitate the enforcement of permitted noise levels during night-time. However, existing night-time noise indices, such as sound exposure level (SEL), maximum sound level (LA max) and night ...