Study Objectives: We introduce new quantitative approaches to study sleep-stage transitions with the goal of addressing the two following questions: (i) Can the new approaches provide more information on the structure of sleep-stage transitions? (ii) How does sleep fragmentation in patients with sleep apnea affect the structure of sleepstage transitions? Design: We analyze hypnograms and compar...

Preschool children with sleep deficit may suffer from autonomic symptoms or hypotension. Heart rate variability, reflecting cardiac parasympathetic and sympathetic activities, and blood pressure were assessed to clarify the effects of nocturnal sleep duration on cardiac autonomic function in 134 preschool children aged 5 and 6 years. Parents reported their children's typical bedtimes and wake t...

Sleep reduction is associated with increased energy intake and weight gain, though few studies have explored the relationship between sleep architecture and energy balance measures in the context of experimental sleep restriction. Fourteen males and 13 females (body mass index: 22-26 kg/m(2)) participated in a crossover sleep curtailment study. Participants were studied under two sleep conditio...

In Japan, percutaneous coronary intervention (PCI) is a major therapeutic intervention for ischemic heart disease (IHD). Previous studies suggested that an association of the risk of IHD caused by sleep duration was related to factors closely associated with daily activities. However, in Japan, there is no study about this relationship objectively measured using the actigraphy in patients with ...

The duration of each episode of any one electrophysiological sleep stage or any episode of intervening wakefulness was determined in three kinds of disturbed sleep, namely, in naturally impaired sleep of late middle-aged, normal people, in sleep after caffeine administration, and in sleep after hypnotic drug withdrawal. When compared with the sleep of young people, the sleep of late middle-aged...

OBJECTIVES Sleep patterns have been linked to various health outcomes, but sleep patterns in the British population have not been extensively reported. We aimed to describe the sleep characteristics reported by the European Prospective Investigation of Cancer (EPIC)-Norfolk participants, with a particular emphasis on the comparison of measures of sleep quantity. METHODS From 2006 to 2007, a t...

During adolescence, there is a tendency to sleep late and sleep less because of altered psychosocial and life-style changes. Recent studies have demonstrated the link between sleeping less and gaining weight in children, adolescents, and adults. We studied the effect of late sleeping and sleeping less on body mass index (BMI) in medical college freshmen. All participants were adolescents (104 m...

Despite mounting evidence that sleep duration is a risk factor across diverse health and functional domains, little is known about the distribution and determinants of sleep. In 2003-2004, the authors used wrist activity monitoring and sleep logs to measure time in bed, sleep latency (time required to fall asleep), sleep duration, and sleep efficiency (percentage of time in bed spent sleeping) ...