Exposure to bright light for several hours during the daytime lowers tympanic temperature

Aizawa, Seika; Tokura, Hiromi

doi:10.1007/s004840050058

Cited by 21 publications

(14 citation statements)

References 8 publications

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“…Therefore, tympanic temperature is often used as an indicator to explain the changes of autonomic and behavioral temperature regulation (Cabanac, 1995). Thus, such different sensitivity between tympanic and rectal temperatures might be probably responsible for different core temperature during the daytime between our present experiment and the one by Aizawa and Tokura (1997). In our experiment, the level of rectal temperature during the nighttime was not different between the two light conditions.…”

Section: Discussionsupporting

confidence: 47%

“…Our results during the daytime were consistent with their findings. On the contrary, Aizawa and Tokura (1997) found that exposure to bright light during the daytime made the tympanic temperature lower significantly in a few hours after light application. These discrepancies probably seemed to reflect the different sensitivity to internal and external stimuli between rectal and tympanic temperatures (Cabanac and Caputa, 1979).…”

Section: Discussionmentioning

confidence: 73%

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Effects of Different Light Intensities during the Daytime on Circadian Rhythm of Core Temperature in Humans.

Park

Tokura

1998

Appl Human Sci

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Abstract. The present study was to determine the effects of bright light exposure during the daytime on core temperature rhythm. Eight female students participated as subjects. They were exposed to bright light of 5000 lux or dim light of 200 lux for 13 hours (06:30-19:30) for two consecutive days. Except the sleep period (22:30-06:30) and during the bright light exposure, light intensity was controlled at 200 lux. Rectal temperature data were collected every 10 min throughout the whole experimental period. The mean level of rectal temperature was not significantly different between the bright and the dim light conditions. However, the evening fall and the morning rise of rectal temperature were significantly greater in the bright light conditions on Day 2 compared to the dim. Furthermore, cosinor analysis showed that the acrophase of rectal temperature rhythm was earlier on Day 2 in the bright light conditions than the dim, and was significantly delayed on Day 2 compared to Day 1 in the dim light conditions. These results suggest that low intensity during the daytime for two consecutive days may induce a phase delay of core temperature rhythm rather than the bright light exposure at least in normally entrained female subjects.

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Section: Discussionsupporting

confidence: 47%

Section: Discussionmentioning

confidence: 73%

Effects of Different Light Intensities during the Daytime on Circadian Rhythm of Core Temperature in Humans.

Park

Tokura

1998

Appl Human Sci

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“…The most important finding is that tympanic temperature gradually decreases slightly, but significantly if the participants spend time under constant bright light (more than 2,000 lx) for several hours during the daytime, compared with dim light (less than 100 lx) (Aizawa and Tokura, 1997, 1998a, 1998b. Similar change may be valid for rectal temperature (Sato et al, 2003).…”

Section: Introduction-light and Core Temperature-supporting

confidence: 53%

How Does Light Intensity Influence Evening Dressing Behavior in the Cold?

Tokura

Kim

2005

J. Physiol. Anthropol.

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Core temperature (tympanic and rectal temperatures) is lowered for several hours under diurnal bright light exposure and its evening fall is inhibited under evening bright light exposure. Melatonin may be involved in the behavior of these core temperatures. Diurnal bright light exposure for several hours may make dressing behavior and thermal sensibility in the evening cold slower and dull, compared with diurnal dim light exposure. On the contrary, evening bright light exposure for several hours may make the dressing behavior and thermal sensibility in the evening cold quicker and sharper, compared with evening dim light exposure. The underlying physiological mechanisms for these findings are that the thermoregulatory set-point would be reduced more markedly in the evening under the influence of higher elevation of melatonin under the diurnal bright light exposure, and its evening decline would be inhibited by suppression of the nocturnal rise of melatonin under evening bright light exposure.

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“…Subjects practiced attaching the sensors several times before experiments. It has been reported that tympanic temperature was affected by ambient illuminance (Aizawa et al, 1997). Horizontal illuminance at the working plane in front of the subject was 909 lx from four fluorescent tubes on the ceiling, which was within the Japanese Industrial Standard (JIS) recommended illuminance range for office work.…”

Section: Measured Variablesmentioning

confidence: 95%

Seasonal Variations of Physiological Characteristics and Thermal Sensation under Identical Thermal Conditions

Umemiya

2006

J Physiol Anthropol

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Seasonal variations of human thermal characteristics were inspected in thermal comfort and when constantly indoors. Metabolic rate, tympanic temperature, skin temperature, body fat, body weight and thermal sensation were measured under identical thermal conditions in a chamber over the course of one year. Experiments were carried out for each subject in both summer and winter. Six subjects were measured 35 times in summer and 45 times in winter. one subject was measured weekly for 14 months. Measurements for analyses were taken 40-60 min after entrance into the chamber. Results revealed the following. 1) For all subjects, the metabolic rate, tympanic temperature and body fat were lower in summer than in winter; thigh skin temperatures were higher in summer than in winter. The averaged individual ratio of seasonal difference was 11.9% for metabolic rate, 14.9% for body fat, 1.8% for thigh temperature and 0.53% for tympanic temperature. Seasonal differences of about 10% in metabolic rate were maintained in this study. 2) Seasonal variations of the variables were examined for phase relationships against the outdoor temperature. 2-1) Metabolic rate, thermal sensation, body weight and body fat changed in reverse phase, whereas skin temperature was in-phase. 2-2) Skin temperature lagged by about one month in both summer and winter. Body fat also lagged by about one month in summer, but corresponded to the phase in winter. Metabolic rates were also in-phase in winter but led about three months in summer. Thermal sensations lagged by about three months in winter but were in-phase in summer. Body weight was in-phase in summer and winter. 2-3) Summer disorders were observed particularly in seasonal variations of metabolic rates, tympanic temperature, skin temperatures, and thermal sensation, thereby suggesting that the effect of temperature exposure was altered by airconditioner use.

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Exposure to bright light for several hours during the daytime lowers tympanic temperature

Cited by 21 publications

References 8 publications

Effects of Different Light Intensities during the Daytime on Circadian Rhythm of Core Temperature in Humans.

Effects of Different Light Intensities during the Daytime on Circadian Rhythm of Core Temperature in Humans.

How Does Light Intensity Influence Evening Dressing Behavior in the Cold?

Seasonal Variations of Physiological Characteristics and Thermal Sensation under Identical Thermal Conditions

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