scholarly journals Body Temperature Frequency Distributions: A Tool for Assessing Thermal Performance in Endotherms?

2021 ◽  
Vol 12 ◽  
Author(s):  
D.L. Levesque ◽  
J. Nowack ◽  
J.G. Boyles

There is increasing recognition that rather than being fully homeothermic, most endotherms display some degree of flexibility in body temperature. However, the degree to which this occurs varies widely from the relatively strict homeothermy in species, such as humans to the dramatic seasonal hibernation seen in Holarctic ground squirrels, to many points in between. To date, attempts to analyse this variability within the framework generated by the study of thermal performance curves have been lacking. We tested if frequency distribution histograms of continuous body temperature measurements could provide a useful analogue to a thermal performance curve in endotherms. We provide examples from mammals displaying a range of thermoregulatory phenotypes, break down continuous core body temperature traces into various components (active and rest phase modes, spreads and skew) and compare these components to hypothetical performance curves. We did not find analogous patterns to ectotherm thermal performance curves, in either full datasets or by breaking body temperature values into more biologically relevant components. Most species had either bimodal or right-skewed (or both) distributions for both active and rest phase body temperatures, indicating a greater capacity for mammals to tolerate body temperatures elevated above the optimal temperatures than commonly assumed. We suggest that while core body temperature distributions may prove useful in generating optimal body temperatures for thermal performance studies and in various ecological applications, they may not be a good means of assessing the shape and breath of thermal performance in endotherms. We also urge researchers to move beyond only using mean body temperatures and to embrace the full variability in both active and resting temperatures in endotherms.

2010 ◽  
Vol 299 (6) ◽  
pp. R1478-R1488 ◽  
Author(s):  
Marshall Hampton ◽  
Bethany T. Nelson ◽  
Matthew T. Andrews

Small hibernating mammals show regular oscillations in their heart rate and body temperature throughout the winter. Long periods of torpor are abruptly interrupted by arousals with heart rates that rapidly increase from 5 beats/min to over 400 beats/min and body temperatures that increase by ∼30°C only to drop back into the hypothermic torpid state within hours. Surgically implanted transmitters were used to obtain high-resolution electrocardiogram and body temperature data from hibernating thirteen-lined ground squirrels ( Spermophilus tridecemlineatus ). These data were used to construct a model of the circulatory system to gain greater understanding of these rapid and extreme changes in physiology. Our model provides estimates of metabolic rates during the torpor-arousal cycles in different model compartments that would be difficult to measure directly. In the compartment that models the more metabolically active tissues and organs (heart, brain, liver, and brown adipose tissue) the peak metabolic rate occurs at a core body temperature of 19°C approximately midway through an arousal. The peak metabolic rate of the active tissues is nine times the normothermic rate after the arousal is complete. For the overall metabolic rate in all tissues, the peak-to-resting ratio is five. This value is high for a rodent, which provides evidence for the hypothesis that the arousal from torpor is limited by the capabilities of the cardiovascular system.


CNS Spectrums ◽  
2008 ◽  
Vol 13 (3) ◽  
pp. 227-229 ◽  
Author(s):  
Alen J. Salerian ◽  
Nansen G. Saleri

ABSTRACTReduction of core body temperature has been proposed to contribute to the increased lifespan and the anti-aging effects conferred by caloric restriction in mice and higher primates. Cooler biologically compatible core body temperatures have also been hypothesized to combat neurodegenerative disorders. Yet, validation of these hypotheses has been difficult until recently, when it demonstrated that transgenic mice engineered to have chronic low core body temperature have longer lifespan independent of alteration in diet or caloric restriction. This article reviews the literature and highlights the potential influence of core body temperature's governing role on aging and in the pathophysiology of neurodegenerative disorders in humans. What makes recent findings more significant for humans is the existence of several methods to lower and maintain low core body temperatures in human subjects. The therapeutic potential of “cooler people” may also raise the possibility that this could reverse the adverse-health consequences of elevations in core body temperature.


1990 ◽  
Vol 68 (1) ◽  
pp. 140-143 ◽  
Author(s):  
Dag Vongraven ◽  
Morten Ekker ◽  
Arild R. Espelien ◽  
Frode J. Aarvik

Postmortem temperature regimes were measured in 11 minke whales, Balaenoptera acutorostrata, at tissue depths varying from 1.5 (in the blubber) to 30 cm, at two different sites on the whales' sides, one in the flipper region (site A) and one in the dorsal fin region (site B). Body temperatures of instantaneously killed whales were assumed to represent those of living animals. Core body temperatures were 35.0 °C at site A and 35.6 °C at site B. Core body temperature and the size of the thermal core were affected by blubber thickness and the time between harpoon strike and death, but were not influenced by duration of pursuit prior to harpooning. Both intra- and inter-specific comparisons reveal that the thickness of the blubber layer is important for the maintenance of thermal gradients and, thereby, for heat conservation.


2021 ◽  
Vol 13 ◽  
Author(s):  
Patrick Eggenberger ◽  
Michael Bürgisser ◽  
René M. Rossi ◽  
Simon Annaheim

Wearable devices for remote and continuous health monitoring in older populations frequently include sensors for body temperature measurements (i.e., skin and core body temperatures). Healthy aging is associated with core body temperatures that are in the lower range of age-related normal values (36.3 ± 0.6°C, oral temperature), while patients with Alzheimer’s disease (AD) exhibit core body temperatures above normal values (up to 0.2°C). However, the relation of body temperature measures with neurocognitive health in older adults remains unknown. This study aimed to explore the association of body temperature with cognitive performance in older adults with and without mild cognitive impairment (MCI). Eighty community-dwelling older adults (≥65 years) participated, of which 54 participants were cognitively healthy and 26 participants met the criteria for MCI. Skin temperatures at the rib cage and the scapula were measured in the laboratory (single-point measurement) and neuropsychological tests were conducted to assess general cognitive performance, episodic memory, verbal fluency, executive function, and processing speed. In a subgroup (n = 15, nine healthy, six MCI), skin and core body temperatures were measured continuously during 12 h of habitual daily activities (long-term measurement). Spearman’s partial correlation analyses, controlled for age, revealed that lower median body temperature and higher peak-to-peak body temperature amplitude was associated with better general cognitive performance and with better performance in specific domains of cognition; [e.g., rib median skin temperature (single-point) vs. processing speed: rs = 0.33, p = 0.002; rib median skin temperature (long-term) vs. executive function: rs = 0.56, p = 0.023; and peak-to-peak core body temperature amplitude (long-term) vs. episodic memory: rs = 0.51, p = 0.032]. Additionally, cognitively healthy older adults showed lower median body temperature and higher peak-to-peak body temperature amplitude compared to older adults with MCI (e.g., rib median skin temperature, single-point: p = 0.035, r = 0.20). We conclude that both skin and core body temperature measures are potential early biomarkers of cognitive decline and preclinical symptoms of MCI/AD. It may therefore be promising to integrate body temperature measures into multi-parameter systems for the remote and continuous monitoring of neurocognitive health in older adults.


In this paper a stochastic differential equation (SDE) model of generic body temperature (such as axilla, mouth, anus, etc.) fluctuation is developed. We consider a mean-reverting SDE process and use zero-mean martingale estimation function to get the parameters. Subsequently we use data generated from another dynamic model of core body temperature a ground truth for comparison with test our SDE model.


2010 ◽  
Vol 299 (3) ◽  
pp. R907-R917 ◽  
Author(s):  
Belinda A. Henry ◽  
Dominique Blache ◽  
Alexandra Rao ◽  
Iain J. Clarke ◽  
Shane K. Maloney

In addition to homeostatic regulation of body mass, nonhomeostatic factors impact on energy balance. Herein we describe effects of temperament on adipose and core body temperatures in sheep. Animals were genetically selected for Nervous or Calm traits. We characterized the effects of 1) high- and low-energy intake and maintenance feeding, 2) meal anticipation, and 3) adrenocorticotropin challenge on core body and adipose temperatures. Temperature measurements (5 min) were made using a thermistor inserted into the carotid artery (core body) and a probe in the retroperitoneal fat. An imposed feeding window was used to establish postprandial elevations in temperature. Fat tissue was taken from retroperitoneal and subcutaneous regions for real-time PCR analyses. We demonstrate that innate differences in temperament impact on adipose and core body temperatures in response to various dietary and evocative stimuli. In response to homeostatic cues (low-energy intake and maintenance feeding) core body temperature tended to be higher in Calm compared with Nervous animals. In contrast, in response to nonhomeostatic cues, Nervous animals had higher anticipatory thermogenic responses than Calm animals. Expression of uncoupling protein (UCP)-1 and -2 mRNA were higher in retroperitoneal tissue than in subcutaneous tissue, but UCP3 and leptin mRNA levels were similar at both sites; expression of these genes was similar in Nervous and Calm animals. There were no differences in stress responsiveness. We conclude that temperament differentially influences adipose thermogenesis and the regulation of core body temperature in responses to both homeostatic and nonhomeostatic stimuli.


2012 ◽  
Vol 26 (2) ◽  
Author(s):  
Joanna Pawlak ◽  
Paweł Zalewski ◽  
Jacek J. Klawe ◽  
Monika Zawadka ◽  
Anna Bitner ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document