Daily rhythms of metabolic heat production, body temperature, and locomotor activity in golden hamsters

1996 ◽  
Vol 21 (4) ◽  
pp. 227-230 ◽  
Author(s):  
Candice M. Brown ◽  
Roberto Refinetti
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Heat Production ◽  
Metabolic Heat Production ◽  
Daily Rhythms ◽  
Metabolic Heat ◽  
Golden Hamsters ◽  
Production Body

scholarly journals Human thermoregulatory responses during serial cold-water immersions

1998 ◽  
Vol 85 (1) ◽  
pp. 204-209 ◽  
Author(s):  
John W. Castellani ◽  
Andrew J. Young ◽  
Michael N. Sawka ◽  
Kent B. Pandolf
Keyword(s):  
Body Temperature ◽  
Rectal Temperature ◽  
Heat Production ◽  
Alternative Explanation ◽  
Cold Water ◽  
Metabolic Heat Production ◽  
Normal Body Temperature ◽  
Repeat Trial ◽  
Metabolic Heat ◽  
Made In

This study examined whether serial cold-water immersions over a 10-h period would lead to fatigue of shivering and vasoconstriction. Eight men were immersed (2 h) in 20°C water three times (0700, 1100, and 1500) in 1 day (Repeat). This trial was compared with single immersions (Control) conducted at the same times of day. Before Repeat exposures at 1100 and 1500, rewarming was employed to standardize initial rectal temperature. The following observations were made in the Repeat relative to the Control trial: 1) rectal temperature was lower and heat debt was higher ( P < 0.05) at 1100; 2) metabolic heat production was lower ( P < 0.05) at 1100 and 1500; 3) subjects perceived the Repeat trial as warmer at 1100. These data suggest that repeated cold exposures may impair the ability to maintain normal body temperature because of a blunting of metabolic heat production, perhaps reflecting a fatigue mechanism. An alternative explanation is that shivering habituation develops rapidly during serially repeated cold exposures.

scholarly journals Does Similar Whole Body Cooling Induce Gender-Specific Attention Stability Deterioration?

2018 ◽  
Vol 1 (96) ◽  
Author(s):  
Rima Solianik ◽  
Albertas Skurvydas ◽  
Marius Brazaitis
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Metabolic Heat Production ◽  
Whole Body ◽  
Complex Task ◽  
Metabolic Heat ◽  
Induced Stress ◽  
Body Cooling ◽  
Whole Body Cooling ◽  
Gender Specific

Background. There is evidence of greater whole body cooling induced unpredictable task switching and memory deterioration in men than in women; however, it is not known how whole body cooling affects attention stability. This study aimed at identifying if there are any gender-specific differences in the effect of cold water immersion-induced stress on attention stability.Methods. Thirteen men and thirteen women were exposed to acute cold stress by immersion in 14°C water until rectal temperature reached 35.5°C or for a maximum of 170 min. Thermoregulatory response (i.e. changes of body temperature and metabolic heat production) and attention stability response (i.e. Schulte table (less cognitively demanding task) and Schulte-Gorbov table (more cognitively demanding task)) were monitored.Results. During cold stress, body temperature variables decreased (p < .05) and did not differ between genders. Metabolic  heat  production  was  greater  (p  <  .05)  in  men  than  in  women.  Body  cooling  significantly  increased  (p < .05) the duration of Schulte table performance for both genders, whereas an increase (p < .05) of the duration of Schulte-Gorbov table performance was observed only in men. Conclusion. This is the first study to find the evidence supporting the idea of gender-specific and task-dependent attention stability response after whole body cooling. Whole body cooling induced stress had similar influence on simple attention stability task in men and women, whereas more complex task was adversely affected only in men. This greater men’s decrement of complex task performance can be associated with their greater catecholamines-induced metabolic heat production.Keywords: men, women, cognitive performance, metabolic heat production, shivering.

Regulation of body temperature in the Budherygah, Melopsittacus undulatus

1976 ◽  
Vol 24 (1) ◽  
pp. 39 ◽  
Author(s):  
WW Weathers ◽  
DC Schoenbaechler
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Water Loss ◽  
Standard Metabolic Rate ◽  
Evaporative Water Loss ◽  
Metabolic Heat Production ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Metabolic Water

The standard metabolic rate of budgerygahs, determined during October and November, was 30% lower at night (1.96 ml O2 g-1 h-1) than during the day (2.55 ml O2 g-1h-1 ). The zone of thermal neutrality extended from 29 to 41�C. At ambient temperatures (Ta) below 29�C, oxygen consumption [V(02)] increased with decreasing Ta according to the relation V(02) (ml O2 g-1 h-1) = 5.65 - 0.127Ta. At Ta's between 0 and 16�C, body temperature (Tb) averaged 37.7�C (which is low by avian standards) and was independent of Ta. Above 20�C, Tb increased with increasing Ta, and within the zone of thermal neutrality Tb increased by approximately 4�C. The relation between V(O2) and Tb within the zone of thermal neutrality is described by the equation V(O2 = 6.29 - 0.105 Tb. This ability to decrease metabolic heat production while Tb rises could contribute to the water economy of budgerygahs. At moderate Ta's the rate of evaporative water loss of budgerygahs is only 60% that predicted for a 31 g bird. At Ta's below 14�C budgerygahs can balance evaporative water loss with metabolic water production. At 45�C Tb was between 1.0 and 5.0�C below Ta, and evaporative cooling accounted for up to 156% of metabolic heat production. At high Ta's budgerygahs appear to augment evaporation by lingual flutter.

Nitric oxide increases cutaneous and respiratory heat dissipation in conscious rabbits

1997 ◽  
Vol 272 (6) ◽  
pp. R1691-R1697 ◽  
Author(s):  
M. L. Mathai ◽  
H. Hjelmqvist ◽  
R. Keil ◽  
R. Gerstberger
Keyword(s):  
Nitric Oxide ◽  
Body Temperature ◽  
Heat Production ◽  
Heat Dissipation ◽  
Metabolic Heat Production ◽  
No Donor ◽  
Evaporative Water ◽  
Deep Body Temperature ◽  
Conscious Rabbit ◽  
Metabolic Heat

The influence of systemic nitric oxide (NO) donor infusion and NO synthase inhibition on major thermoregulatory mechanisms was investigated under thermoneutral conditions (24 degrees C) in the conscious rabbit. Both low (25 nmol.min-1.kg-1) and high-dose (75 nmol.min-1.kg-1) infusion of the NO donors 3-morpholinosydnonimine-hydrochloride and S-nitroso-N-acetylpenicillamine augmented respiratory heat dissipation due to raised respiratory frequency (RF) and evaporative water loss (REWL). At the higher dose of NO donor, RF and REWL increased (from 107 +/- 16 to 156 +/- 19 breaths/min and from 7.12 +/- 0.97 to 11.29 +/- 1.29 mg.min-1.kg-1; P < 0.05), and, combined with a moderate rise in cutaneous heat dissipation (ear skin temperature increased from 29.03 +/- 1.76 to 33.29 +/- 2.71 degrees C; P < 0.05), deep body temperature was slightly reduced (-0.1 degrees C, P > 0.05) without a change in metabolic heat production. In contrast, blockade of endogenous NO synthesis induced a sustained rise in body temperature (0.2 degrees C, P < 0.05), concomitant with a reduction in both RF and REWL (from 131 +/- 11 to 94 +/- 12 breaths/min and from 10.86 +/- 1.14 to 8.70 +/- 0.88 mg.min-1.kg-1, P < 0.05), whereas metabolic heat production decreased slightly and cutaneous heat dissipation was minimally altered. The data indicate that, under thermoneutral conditions, systemically applied NO primarily influences body temperature in the conscious rabbit by modulating the rate of respiratory heat dissipation, whereas the roles of cutaneous heat dissipation and metabolic heat production are relatively minor.

Regulated nocturnal hypothermia induced in pigeons by food deprivation

1989 ◽  
Vol 256 (3) ◽  
pp. R733-R738 ◽  
Author(s):  
R. Graf ◽  
S. Krishna ◽  
H. C. Heller
Keyword(s):  
Spinal Cord ◽  
Body Temperature ◽  
Food Deprivation ◽  
Heat Production ◽  
Metabolic Heat Production ◽  
Threshold Temperature ◽  
Feedback Parameter ◽  
Metabolic Heat ◽  
Spinal Cord Temperature ◽  
Thermoregulatory System

The daily body temperature (Tb) cycle of pigeons is altered by food deprivation in that Tb falls to lower and lower levels on consecutive nights after the onset of deprivation, whereas the Tb levels during corresponding days remain nearly unchanged. Manipulations of spinal cord temperature, a major feedback parameter in the avian thermoregulatory system, reveal that episodes of nocturnal hypothermia are regulated. The spinal cord threshold temperature for inducing increases in metabolic heat production falls to progressively lower levels each night and returns to normal euthermic levels during the day.

Effect of wind and solar radiation on metabolic heat production in a small desert rodent, Spermophilus tereticaudus

2000 ◽  
Vol 203 (5) ◽  
pp. 879-888 ◽  
Author(s):  
K.M. Wooden ◽  
G.E. Walsberg
Keyword(s):  
Wind Speed ◽  
Body Temperature ◽  
Solar Radiation ◽  
Heat Production ◽  
Tissue Level ◽  
Short Wave ◽  
Metabolic Heat Production ◽  
Metabolic Heat ◽  
Simulated Solar Radiation ◽  
Solar Radiation Exposure

To understand better how complex interactions between environmental variables affect the energy balance of small diurnal animals, we studied the effects of the absence and presence of 950 W m(−)(2) simulated solar radiation combined with wind speeds ranging from 0. 25 to 1.00 m s(−)(1) on the metabolic rate and body temperature of the round-tailed ground squirrel Spermophilus tereticaudus. As wind speed increased from 0.25 to 1.00 m s(−)(1), metabolic heat production increased by 0.94 W in the absence of solar radiation and by 0.98 W in the presence of 950 W m(−)(2) simulated solar radiation. Exposure to simulated solar radiation reduced metabolic heat production by 0.68 W at a wind speed of 0.25 m s(−)(1), by 0.64 W at 0.50 m s(−)(1) and by 0.64 W at 1.00 m s(−)(1). Body temperature was significantly affected by environmental conditions, ranging from 32. 5 degrees C at a wind speed of 1.0 m s(−)(1) and no irradiance to 35. 6 degrees C at a wind speed of 0.50 m s(−)(1) with 950 W m(−)(2)short-wave irradiance. In addition, several unusual findings resulted from this study. The coat of S. tereticaudus is very sparse, and the observed heat transfer of 5.68+/−0.37 W m(−)(2) degrees C(−)(1) (mean +/− s.e.m., N=11) is much higher than expected from either allometric equations or comparative studies with other rodents of similar mass. Solar heat gain was remarkably low, equalling only 10 % of intercepted radiation and suggesting a remarkably high regional thermal resistance at the tissue level. Animals remained normally active and alert at body temperatures as low as 32.5 degrees C. These findings suggest a unique combination of adaptations that allow S. tereticaudus to exploit a harsh desert environment.

scholarly journals Dinosaur body temperatures: the occurrence of endothermy and ectothermy

Paleobiology ◽  
2003 ◽  
Vol 29 (1) ◽  
pp. 105-122 ◽  
Author(s):  
Frank Seebacher
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Field Data ◽  
Metabolic Heat Production ◽  
Biophysical Model ◽  
Large Species ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Metabolic Heat ◽  
Thermal Relations

Despite numerous studies, the thermal physiology of dinosaurs remains unresolved. Thus, perhaps the commonly asked question whether dinosaurs were ectotherms or endotherms is inappropriate, and it is more constructive to ask which dinosaurs were likely to have been endothermic and which ones ectothermic. Field data from crocodiles over a large size range show that body temperature fluctuations decrease with increasing body mass, and that average daily body temperatures increase with increasing mass. A biophysical model, the biological relevance of which was tested against field data, was used to predict body temperatures of dinosaurs. However, rather than predicting thermal relations of a hypothetical dinosaur, the model considered correct paleogeographical distribution and climate to predict the thermal relations of a large number of dinosaurs known from the fossil record (>700). Many dinosaurs could have had “high” (>30°) and stable (daily amplitude >2°) body temperatures without metabolic heat production even in winter, so it is unlikely that selection pressure would have favored the evolution of elevated resting metabolic rates in those species. Recent evidence of ontogenetic growth rates indicates that even the juveniles of large species (3000–4000 kg) could have had biologically functional body temperature ranges during early development. Smaller dinosaurs (<100 kg) at mid to high latitudes (>45°) could not have had high and stable body temperatures without metabolic heat production. However, elevated metabolic rates were unlikely to have provided selective advantage in the absence of some form of insulation, so probably insulation was present before endothermy evolved, or else it coevolved with elevated metabolic rates. Superimposing these findings onto a phylogeny of the Dinosauria suggests that endothermy most likely evolved among the Coelurosauria and, to a lesser extent, among the Hypsilophodontidae, but not among the Stegosauridae, Nodosauridae, Ankylosauridae, Hadrosauridae, Ceratopsidae, Prosauropoda, and Sauropoda.

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