Bonnet MH, Arand DL. 24-Hour metabolic rate in insomniacs and matched normal sleepers. Sleep 18: 581-8

Dayton VA Hospital, Wright State University, Ohio, USA.
Sleep (Impact Factor: 4.59). 10/1995; 18(7):581-8.
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Groups of 10 objectively defined insomniacs and age-, sex- and weight-matched normal sleepers were evaluated on sleep, performance, mood, personality and metabolic measures over a 36-hour sleep laboratory stay. Insomniacs were defined to have increased wake time during the night but also had decreased stage 2 and rapid eye movement sleep. As expected insomniacs reported increased confusion, tension and depression and decreased vigor on the profile of mood states mood scale throughout the evaluation period as compared to the normals. Insomniacs also had decreased memory ability on the short-term memory test and the MAST. These performance and mood differences were not secondary to sleepiness because the insomniacs also had significantly increased multiple sleep latency test (MSLT) values throughout the evaluation period. In conjunction with the consistent mood, performance and MSLT differences during the day and the sleep differences at night, whole body VO2, measured at intervals across the day and throughout one night of sleep, was consistently elevated at all measurement points in the insomniacs as compared to the normals. The nocturnal increase in metabolic rate remained even after metabolic values from periods during the night containing wake time or arousals were eliminated from the data set. It was concluded that patients who report chronic insomnia may suffer from a more general disorder of hyperarousal (as measured here by a 24-hour increase in metabolic rate) that may be responsible for both the daytime symptoms and the nocturnal poor sleep. Future studies need to explore 24-hour insomnia treatment strategies that decrease hyperarousal.

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    • "Insomnia is estimated to affect approximately 10% of the adult population (Morin et al., 2006), and is associated with chronic symptoms of fatigue (Orff et al., 2007), impairment of sustained attention (Altena et al., 2008), poorer working memory (Bonnet and Arand, 1995) and degraded quality of life (Bolge et al., 2009). Given this, insomnia is also regarded as a significant public health issue (Altevogt and Colten, 2006). "
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    ABSTRACT: While high levels of activity and exercise training have been associated with improvements in sleep quality, minimum levels of activity likely to improve sleep outcomes have not been explored. A two-armed parallel randomized controlled trial (N=41; 30 females) was designed to assess whether increasing physical activity to the level recommended in public health guidelines can improve sleep quality among inactive adults meeting research diagnostic criteria for insomnia. The intervention consisted of a monitored program of ≥150 min of moderate- to vigorous-intensity physical activity per week, for 6 months. The principal end-point was the Insomnia Severity Index at 6 months post-baseline. Secondary outcomes included measures of mood, fatigue and daytime sleepiness. Activity and light exposure were monitored throughout the trial using accelerometry and actigraphy. At 6 months post-baseline, the physical activity group showed significantly reduced insomnia symptom severity (F8,26 = 5.16, P = 0.03), with an average reduction of four points on the Insomnia Severity Index; and significantly reduced depression and anxiety scores (F6,28 = 5.61, P = 0.02; and F6,28 = 4.41, P = 0.05, respectively). All of the changes were independent of daily light exposure. Daytime fatigue showed no significant effect of the intervention (F8,26 = 1.84, P = 0.18). Adherence and retention were high. Internationally recommended minimum levels of physical activity improve daytime and night-time symptoms of chronic insomnia independent of daily light exposure levels. © 2015 European Sleep Research Society.
    Journal of Sleep Research 04/2015; 24(5). DOI:10.1111/jsr.12297 · 3.35 Impact Factor
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    • "Notwithstanding, brain mechanisms of insomnia have remained elusive, hampering the development of effective treatments. The symptoms of insomnia are not limited to sleep and may best be summarized as a round-the-clock state of hyper-arousal (Bonnet and Arand, 1995). Indeed, subjective hyper-arousal indices like tension, irritability, hypersensitivity and behavioural hyper-responsivity are complemented by physiological indices of hyper-arousal. "
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    ABSTRACT: Insomnia is prevalent, severe and partially heritable. Unfortunately, its neuronal correlates remain enigmatic, hampering the development of mechanistic models and rational treatments. Consistently reported impairments concern fragmented sleep, hyper-arousal and executive dysfunction. Because fronto-striatal networks could well play a role in sleep, arousal regulation and executive functioning, the present series of studies used an executive task to evaluate fronto-striatal functioning in disturbed sleep. Patients with insomnia showed reduced recruitment of the head of the left caudate nucleus during executive functioning, which was not secondary to altered performance or baseline perfusion. Individual differences in caudate recruitment were associated with hyper-arousal severity. Seed-based functional connectivity analysis suggested that attenuated input from a projecting orbitofrontal area with reduced grey matter density contributes to altered caudate recruitment in patients with insomnia. Attenuated caudate recruitment persisted after successful treatment of insomnia, warranting evaluation as a potential vulnerability trait. A similar selective reduction in caudate recruitment could be elicited in participants without sleep complaints by slow-wave sleep fragmentation, providing a model to facilitate investigation of the causes and consequences of insomnia.
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    • "Patients with insomnia, despite lacking night sleep and day-time fatigue, are at a higher state of alertness than those who have appropriate sleep, which has also been demonstrated by the fact that patients with insomnia have longer sleep latency than a control group consisting of ordinary people who sleep upon an execution of latency repeat inspection. This suggests that insomnia is an over-alertness obstacle ranging for 24 hours, and not one limited only to nighttime [78]. As another piece of evidence of over-alertness, patients with insomnia have an increased metabolic rate for 24 hours, their sympathetic nervous system is relatively exacerbated [78], and their adrenal cortex hormone and cortisol density are markedly increased compared to ordinary people [2]. "
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