Effects of mild heat exposure on sleep stages and body temperature in older men

Okamoto-Mizuno, Kazue; Tsuzuki, Kazuyo; Mizuno, Koji

doi:10.1007/s00484-004-0209-3

Cited by 57 publications

(42 citation statements)

References 34 publications

(43 reference statements)

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“…In summer, there can be competition between sleep maintenance and the thermoregulatory system as the neural mechanism controlling sleep receives input from the hypothalamus and peripheral temperature receptors (Sakaguchi et al 1979). In a previous study, a Ta of 32°C increased wakefulness and suppressed REM in older men (Okamoto-Mizuno et al 2004). Although the Ta of the present study was lower than that reported in the previous study, wakefulness was significantly increased.…”

Section: Discussioncontrasting

confidence: 51%

Effects of season on sleep and skin temperature in the elderly

Okamoto-Mizuno

Tsuzuki

2009

Int J Biometeorol

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The effects of season on sleep and skin temperature (Tsk) in 19 healthy, elderly volunteers were investigated. Measurements were obtained in summer, winter, and fall, and activity levels were monitored using a wrist actigraph system for five consecutive days. The temperature and humidity of the bedrooms of the subjects' homes were measured continuously for five days. During actigraphic measurement, Tsk during sleep was measured for two nights. The bedroom temperature and humidity significantly increased in summer compared to winter and fall. In summer, the total sleep time decreased (mean +/- SE min; summer, 350.8 +/- 15.7; winter, 426.5 +/- 14.2; fall, 403.2 +/- 16.4) and wakefulness increased (P < 0.003) compared to those in fall or winter. The sleep efficiency index that was derived from wrist actigraphy was significantly decreased (P < 0.001) in summer (81.4 +/- 2.9%) compared with winter (91.6 +/- 1.3%) or fall (90.2 +/- 1.2%). The forehead Tsk significantly increased, while the chest and thigh Tsks were decreased in summer compared to those in fall or winter. These results suggest that, in the elderly, sleep is disturbed in summer more than in other seasons, and that this disturbance is related to fluctuations in Tsk.

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Section: Discussioncontrasting

confidence: 51%

Effects of season on sleep and skin temperature in the elderly

Okamoto-Mizuno

Tsuzuki

2009

Int J Biometeorol

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“…Although ambient temperature can not be ignored, it should be noted that passive heating with a warm footbath in this study had minimal effects on either objective or perceived sleep outcomes in older adults. Reduced heat dissipation capacity in older adults (Dorsey et al, 1999; Minson, Holowatz, Wong, Kenney, & Wilkins, 2002; Okamoto-Mizuno, Tsuzuki, & Mizuno, 2004), rather than effects of ambient temperature, may be a more plausible explanation for our observed effects of a foot bath on body temperature in older adults.…”

Section: Discussionmentioning

confidence: 87%

A warm footbath before bedtime and sleep in older Taiwanese with sleep disturbance

Liao

Chiu

Landis

2008

Research in Nursing & Health

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A single-group crossover design was used to examine the effects of a warm footbath on body temperatures, distal-proximal skin temperature gradient (DPG), and sleep outcomes in 15 Taiwanese elders with self-reported sleep disturbance. Body temperatures and polysomnography were recorded for 3 consecutive nights. Participants were assigned randomly to receive a 41°C footbath for 40 minutes before sleep onset on night 2 or night 3. Mean DPG before lights off was significantly elevated on the bathing night. There were no significant differences in sleep outcomes between the two nights. However, when the first two non-rapid eye movement (NREM) sleep periods were examined, the amount of wakefulness was decreased in the second NREM period on the bathing night. Keywords sleep/rest; agingInsomnia is a common complaint in older adults. They have trouble falling asleep, as well as frequent or prolonged nocturnal or early morning awakenings with an inability to return to sleep (Ancoli-Israel, 1997;Ancoli-Israel & Roth, 1999;Floyd, Medler, Ager, & Janisse, 2000). The overall prevalence of insomnia in the elderly ranges from 14.0% -42.2% based on epidemiological surveys (Chiu et al., 1999;Kim, Uchiyama, Okawa, Liu, & Ogihara, 2000;Ohayon, 1996). As many as 25% of healthy elderly men and women may have chronic insomnia (Ohayon & Smirne, 2002). Global sleep dissatisfaction, defined as overall dissatisfaction with sleep, ranges from 7.7 -20.8% in the elderly, which is higher than in the general population (7.0-10.1%; Pallesen et al., 2001).Sleep is periodic resting behavior characterized by "few body movements, a recumbent posture, and complex brain electroencephalographic activity" (Carskadon & Dement, 2000, p.15). Human sleep architecture is defined by polysomnography (PSG) and divided into stages: four of non-rapid eye movement (NREM) sleep (stage 1 to 4), and one stage of rapid-eye movement (REM) sleep (Rechtschaffen & Kales 1968 Age has large effects on sleep architecture. Compared to young adults, PSG-derived sleep architecture in older adults shows increased amounts of nocturnal wakefulness, increased NREM stage 1 sleep with reduced amounts or complete absence of NREM stages 3 and 4 sleep (Floyd et al., 2000;Van Someren, 2000a). In some studies, the percentage of REM sleep was reduced slightly in older adults (Van Cauter, Leproult, & Plat, 2000), whereas findings from other studies showed that older adults experienced typical amounts of REM sleep (Campbell & Murphy, 1998). Long sleep latencies (e.g. > 30 minutes), reduced sleep efficiency (e.g. < 85%), and a sleep duration of ≤ 6 hours were common in older adults. These characteristics are consistent with the criteria of insomnia, although not all older adults complained of poor sleep (Vitiello, Larsen, & Moe, 2004).In addition to changes in sleep architecture, there are changes in the circadian rhythm of body temperature in older adults compared to young adults. A circadian rhythm is the variation in body functions and behaviors that occur in a regular pattern ar...

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“…The amount of REM sleep during summer remained almost at the basal level. The effect of acute exposure to warm ambient temperature on sleep has been studied extensively on human volunteers in controlled laboratory conditions (Karacan et al 1978;Muzet et al 1983;Libert et al 1988;OkamotoMizuno et al 1999;Okamoto-Mizuno et al 2004). These studies indicated that TST, stages 1 and 2, stages 3 and 4 and REM sleep decreased, with frequent and longer awakenings, greater shifting among sleep stages, and delayed onset of deep sleep (stages 3 and 4).…”

Section: Discussionmentioning

confidence: 99%

Changes in sleep patterns during prolonged stays in Antarctica

et al. 2008

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Various countries have permanent research bases in Antarctica that are manned year-round by a few members of an expedition team, facing extremes of temperature with the associated hardships. Acclimatisation to such an environment is associated with pyschophysiological changes along with alterations in sleep patterns. The present study was undertaken to explore the changes in sleep patterns of six members of the Indian expedition team during their winter stay at Maitri, the permanent research station of India in Antarctica. The mean (+/- SEM) age, height and weight of the subjects were 35.7 +/- 2.32 years, 168.3 +/- 2.37 cm and 71.0 +/- 1.88 kg, respectively. Polysomnographic sleep recordings were obtained as baseline data in November 2004 in Delhi (altitude 260 m, latitude 29 degrees N, longitude 77 degrees E); data on the same parameters were collected at Maitri, Antarctica (altitude 120 m, latitude 70 degrees 45' 39'' S, longitude 11 degrees 44' 49'' E) from January to December 2005. A one-way analysis of variance with repeated measures showed a significant variation with time (month effect) in most of the sleep parameters recorded. Total sleep time decreased from Delhi baseline values in all months, sleep efficiency decreased significantly during winter months, duration of waking period after sleep onset increased significantly in winter, sleep latency increased immediately after exposure in January, stages 3 and 4 (slow wave sleep) reduced during dark winter months, whereas stages 1 and 2 and rapid eye movement sleep increased during dark winter months. This study observed a prevailing general trend of sleep disturbances amongst overwintering members in a modern Antarctic station.

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Effects of mild heat exposure on sleep stages and body temperature in older men

Cited by 57 publications

References 34 publications

Effects of season on sleep and skin temperature in the elderly

Effects of season on sleep and skin temperature in the elderly

A warm footbath before bedtime and sleep in older Taiwanese with sleep disturbance

Changes in sleep patterns during prolonged stays in Antarctica

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