Altered phase relation between sleep timing and core body temperature rhythm in delayed sleep phase syndrome and non-24-hour sleep–wake syndrome in humans

An increase in variation in the 24 h pattern of body temperature (heterothermy) in mammals can be induced by energy and water deficits. Since performance traits such as growth and reproduction also are impacted by energy and water balance, we investigated whether the characteristics of the body temperature rhythm provide an indication of the reproductive success of an individual. We show that the amplitude of the daily rhythm of body temperature in wild rabbits ( Oryctolagus cuniculus ) prior to breeding is inversely related to the number of pregnancies in the subsequent seven months, while the minimum daily body temperature is positively correlated to the number of pregnancies. Because reproductive output could be predicted from characteristics of the core body temperature rhythm prior to the breeding season, we propose that the pattern of the 24 h body temperature rhythm could provide an index of animal fitness in a given environment.

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Body Temperature Monitoring in Subjects with Delayed Sleep Phase Syndrome

Neuropsychobiology ◽

10.1159/000118495 ◽

1988 ◽

Vol 20 (4) ◽

pp. 174-177 ◽

Cited By ~ 12

Author(s):

Norio Ozaki ◽

Tokihisa Iwata ◽

Akinori Itoh ◽

Susumu Kogawa ◽

Tatsuro Ohta ◽

...

Keyword(s):

Body Temperature ◽

Temperature Monitoring ◽

Sleep Phase ◽

Delayed Sleep Phase Syndrome ◽

Delayed Sleep Phase ◽

Delayed Sleep

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Modification of circadian body temperature rhythm during the luteal menstrual phase: role of melatonin

Journal of Applied Physiology ◽

10.1152/jappl.1996.80.1.25 ◽

1996 ◽

Vol 80 (1) ◽

pp. 25-29 ◽

Cited By ~ 44

Author(s):

A. Cagnacci ◽

R. Soldani ◽

G. A. Laughlin ◽

S. S. Yen

Keyword(s):

Body Temperature ◽

Core Body Temperature ◽

Menstrual Phase ◽

Temperature Rhythm ◽

Melatonin Administration ◽

Early Follicular Phase ◽

Body Temperature Rhythm ◽

The Mean ◽

Core Body

In women during early follicular phase (FP), the rise of melatonin at night accounts for 40% of the nocturnal core body temperature (Tc) decline. In seven normal-cycling women, the circadian rhythms of Tc and melatonin of the FP were compared with those of the luteal phase (LP). In addition, in both phases the Tc response to daytime melatonin administration was investigated. Melatonin levels were comparable during the two menstrual phases, but the nocturnal melatonin onset was delayed by 90 min in the LP (P < 0.01). This was accompanied by a delay of the nadir of the Tc circadian rhythm (P < 0.002), a 0.3 degrees C elevation (P < 0.005) of the mean 24-h value, and a 40% blunting (P < 0.002) of the amplitude. This attenuation of circadian Tc in LP women was replicated in two estrogen-treated hypogonadal women by the administration of medroxyprogesterone acetate. The daytime administration of melatonin (2.5 mg) decreased Tc during the FP (P < 0.01) but was ineffective in the LP. Present data indicate that in LP, in association with high progesterone levels, an attenuated and phase-delayed circadian Tc rhythm may, in part, be due to a reduced effect of melatonin.

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