Disturbance of thermal homeostasis following dynamic exercise

2007 ◽  
Vol 32 (4) ◽  
pp. 818-831 ◽  
Author(s):  
Glen P. Kenny ◽  
Ollie Jay ◽  
W. Shane Journeay
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Core Body Temperature ◽  
Dynamic Exercise ◽  
Hemodynamic Changes ◽  
Post Exercise ◽  
Cutaneous Vasodilation ◽  
Baseline Values ◽  
Sudomotor Activity ◽  
Core Body

Recovery from dynamic exercise results in significant perturbations of thermoregulatory control. These perturbations evoke a prolonged elevation in core body temperature and a concomitant decrease in sweating, skin blood flow, and skin temperature to pre-exercise baseline values within the early stages of recovery. Cutaneous vasodilation and sweating are critical responses necessary for effective thermoregulation during heat stress in humans. The ability to modulate the rate of heat loss through adjustments in vasomotor and sudomotor activity is a fundamental mechanism of thermoregulatory homeostasis. There is a growing body of evidence in support of a possible relationship between hemodynamic changes postexercise and heat loss responses. Specifically, nonthermoregulatory factors, such as baroreceptors, associated with hemodynamic changes, influence the regulation of core body temperature during exercise recovery. The following review will examine the etiology of the post-exercise disturbance in thermal homeostasis and evaluate possible thermal and nonthermal factors associated with a prolonged hyperthermic state following exercise.

Infrared thermal imaging as a method to study thermogenesis in the neonatal lamb

2014 ◽  
Vol 54 (9) ◽  
pp. 1497 ◽  
Author(s):  
S. A. McCoard ◽  
H. V. Henderson ◽  
F. W. Knol ◽  
S. K. Dowling ◽  
J. R. Webster
Keyword(s):  
Body Temperature ◽  
Heat Loss ◽  
Cold Exposure ◽  
Thermal Imaging ◽  
Core Body Temperature ◽  
Recovery Period ◽  
Exposure Period ◽  
Skin Surface ◽  
Infrared Thermal Imaging ◽  
Core Body

The combination of heat generation and reducing heat loss from the skin surface is important for maintaining core body temperature in a neonate. Thermogenesis studies traditionally focus on measurement of core body temperature but not the contribution of radiated heat loss at the skin surface. This study aimed to evaluate the utility of using thermal imaging to measure radiated heat loss in newborn lambs. Continuous thermal images of newborn lambs were captured for 30 min each during the baseline (11−18°C), cold-exposure (0°C) and recovery (11−18°C) periods by using an infrared camera. Core body temperature measured by rectal thermometer was also recorded at the end of each period. In all, 7 of the 10 lambs evaluated had reduced rectal temperatures (0.4−1°C) between the baseline and recovery periods, while three maintained body temperature despite cold exposure. During the baseline period, infrared heat loss was relatively stable, followed by a rapid decrease of 5°C within 5 min of cold exposure. Heat loss continued to decrease linearly in the cold-exposure period by a further 10°C, but increased rapidly to baseline levels during the recovery period. A temperature change of between 20°C and 35°C was observed during the study, which was likely to be due to changes in vasoconstriction in the skin to conserve heat. The present study has highlighted the sensitivity of infrared thermal imaging to estimate heat loss from the skin in the newborn lamb and shown that rapid changes in heat loss occur in response to cold exposure.

scholarly journals Elevated body temperature during sleep in orexin knockout mice

2006 ◽  
Vol 291 (3) ◽  
pp. R533-R540 ◽  
Author(s):  
Takatoshi Mochizuki ◽  
Elizabeth B. Klerman ◽  
Takeshi Sakurai ◽  
Thomas E. Scammell
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Heat Loss ◽  
Core Body Temperature ◽  
Biological Rhythms ◽  
Physiological Factors ◽  
Sustained Activity ◽  
Recovery Sleep ◽  
Core Body ◽  
Elevated Body Temperature

Core body temperature (Tb) is influenced by many physiological factors, including behavioral state, locomotor activity, and biological rhythms. To determine the relative roles of these factors, we examined Tb in orexin knockout (KO) mice, which have a narcolepsy-like phenotype with severe sleep-wake fragmentation. Because orexin is released during wakefulness and is thought to promote heat production, we hypothesized that orexin KO mice would have lower Tb while awake. Surprisingly, Tb was the same in orexin KO mice and wild-type (WT) littermates during sustained wakefulness. Orexin KO mice had normal diurnal variations in Tb, but the ultradian rhythms of Tb, locomotor activity, and wakefulness were markedly reduced. During the first 15 min of spontaneous sleep, the Tb of WT mice decreased by 1.0°C, but Tb in orexin KO mice decreased only 0.4°C. Even during intense recovery sleep after 8 h of sleep deprivation, the Tb of orexin KO mice remained 0.7°C higher than in WT mice. This blunted fall in Tb during sleep may be due to inadequate activation of heat loss mechanisms or sustained activity in heat-generating systems. These observations reveal an unexpected role for orexin in thermoregulation. In addition, because heat loss is an essential aspect of sleep, the blunted fall in Tb of orexin KO mice may provide an explanation for the fragmented sleep of narcolepsy.

Core body temperature changes after sauna exposition in healthy subjects

2012 ◽  
Vol 26 (2) ◽  
Author(s):  
Joanna Pawlak ◽  
Paweł Zalewski ◽  
Jacek J. Klawe ◽  
Monika Zawadka ◽  
Anna Bitner ◽  
...  
Keyword(s):  
Body Temperature ◽  
Healthy Subjects ◽  
Core Body Temperature ◽  
Temperature Changes ◽  
Core Body
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