scholarly journals Comparisons of core temperature between a telemetric pill and heart rate estimated core temperature in firefighters

2021 ◽  
Author(s):  
Stephen J. Pearson ◽  
Brian Highlands ◽  
Rebecca Jones ◽  
Martyn J. Mattthews
Keyword(s):  
Heart Rate ◽  
Core Temperature

Hypothalamic paraventricular nucleus is critical for renal vasoconstriction elicited by elevations in body temperature

2008 ◽  
Vol 294 (2) ◽  
pp. F309-F315 ◽  
Author(s):  
Joo Lee Cham ◽  
Emilio Badoer
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Core Temperature ◽  
Paraventricular Nucleus ◽  
Hypothalamic Paraventricular Nucleus ◽  
Body Core Temperature ◽  
Control Group ◽  
Body Core

Redistribution of blood from the viscera to the peripheral vasculature is the major cardiovascular response designed to restore thermoregulatory homeostasis after an elevation in body core temperature. In this study, we investigated the role of the hypothalamic paraventricular nucleus (PVN) in the reflex decrease in renal blood flow that is induced by hyperthermia, as this brain region is known to play a key role in renal function and may contribute to the central pathways underlying thermoregulatory responses. In anesthetized rats, blood pressure, heart rate, renal blood flow, and tail skin temperature were recorded in response to elevating body core temperature. In the control group, saline was microinjected bilaterally into the PVN; in the second group, muscimol (1 nmol in 100 nl per side) was microinjected to inhibit neuronal activity in the PVN; and in a third group, muscimol was microinjected outside the PVN. Compared with control, microinjection of muscimol into the PVN did not significantly affect the blood pressure or heart rate responses. However, the normal reflex reduction in renal blood flow observed in response to hyperthermia in the control group (∼70% from a resting level of 11.5 ml/min) was abolished by the microinjection of muscimol into the PVN (maximum reduction of 8% from a resting of 9.1 ml/min). This effect was specific to the PVN since microinjection of muscimol outside the PVN did not prevent the normal renal blood flow response. The data suggest that the PVN plays an essential role in the reflex decrease in renal blood flow elicited by hyperthermia.

scholarly journals Estimating Resting Core Temperature Using Heart Rate

2018 ◽  
Vol 1 (2) ◽  
pp. 79-86 ◽  
Author(s):  
David P. Looney ◽  
Mark J. Buller ◽  
Andrei V. Gribok ◽  
Jayme L. Leger ◽  
Adam W. Potter ◽  
...  
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Estimation Algorithm ◽  
Quadratic Equation ◽  
Estimation Accuracy ◽  
Future Research ◽  
Accuracy And Precision ◽  
Military Populations ◽  
Thermal Work ◽  
Ct Data

ECTemp™ is a heart rate (HR)-based core temperature (CT) estimation algorithm mainly used as a real-time thermal-work strain indicator in military populations. ECTemp™ may also be valuable for resting CT estimation, which is critical for circadian rhythm research. This investigation developed and incorporated a sigmoid equation into ECTemp™ to better estimate resting CT. HR and CT data were collected over two calorimeter test trials from 16 volunteers (age, 23 ± 3 yrs; height, 1.72 ± 0.07 m; body mass, 68.5 ± 8.1 kg) during periods of sleep and inactivity. Half of the test trials were combined with ECTemp™’s original development dataset to train the new sigmoid model while the other was used for model validation. Models were compared by their estimation accuracy and precision. While both models produced accurate CT estimates, the sigmoid model had a smaller bias (−0.04 ± 0.26°C vs. −0.19 ± 0.29°C) and root mean square error (RMSE; 0.26°C vs. 0.35°C). ECTemp™ is a validated HR-based resting CT estimation algorithm. The new sigmoid equation corrects lower CT estimates while producing nearly identical estimates to the original quadratic equation at higher CT. The demonstrated accuracy of ECTemp™ encourages future research to explore the algorithm’s potential as a non-invasive means of tracking CT circadian rhythms.

scholarly journals Heart Rate And Core Temperature Responses Of Pit Crew Athletes During Elite Automobile Races.

2009 ◽  
Vol 41 ◽  
pp. 147
Author(s):  
David P. Ferguson ◽  
Trudy L. Moore-Harrison ◽  
Robert S. Bowen ◽  
Katrina J. Hall ◽  
Emily E. Schmitt ◽  
...  
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Temperature Responses

11 Circadian Rhythm of Core Temperature, Blood Pressure and Heart Rate in Hypothyroid and Normal Rats

2015 ◽  
pp. 55-59
Author(s):  
P De Remigis ◽  
P Cugini ◽  
F Halberg ◽  
S Sensi ◽  
D Scavo
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Circadian Rhythm ◽  
Core Temperature

Oxygen pulse in guinea pigs in hyperbaric helium and hydrogen

1997 ◽  
Vol 82 (3) ◽  
pp. 988-997 ◽  
Author(s):  
Susan R. Kayar ◽  
Erich C. Parker
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Guinea Pigs ◽  
Multivariate Regression Analysis ◽  
Heart Beat ◽  
Hyperbaric Chamber ◽  
Oxygen Pulse ◽  
Chamber Temperature ◽  
Hyperbaric Environment ◽  
Temperature And Pressure

Kayar, Susan R., and Erich C. Parker. Oxygen pulse in guinea pigs in hyperbaric helium and hydrogen. J. Appl. Physiol. 82(3): 988–997, 1997.—We analyzed O2 pulse, the total volume of O2 consumed per heart beat, in guinea pigs at pressures from 10 to 60 atmospheres. Animals were placed in a hyperbaric chamber and breathed 2% O2 in either helium (heliox) or hydrogen (hydrox). Oxygen consumption rate (V˙o 2) was measured by gas chromatographic analysis. Core temperature and heart rate were measured by using surgically implanted radiotelemeters. TheV˙o 2 was modulated over a fourfold range by varying chamber temperature from 25 to 36°C. There was a direct correlation betweenV˙o 2 and heart rate, which was significantly different for animals in heliox vs. hydrox ( P = 0.003). By using multivariate regression analysis, we identified variables that were significant to O2 pulse: body surface area, chamber temperature, core temperature, and pressure. After normalizing for all nonpressure variables, the residual O2 pulse was found to decrease significantly ( P = 0.02) with pressure for animals in heliox but did not decrease significantly ( P = 0.38) with pressure for animals in hydrox over the range of pressures studied. This amounted to a roughly 25% lower O2 pulse for normothermic animals in 60 atmospheres heliox vs. hydrox. These results suggest that reduction of cardiovascular efficiency in a hyperbaric environment can be mitigated by the choice of breathing gas.

Perceived Exertion during Physical Exercise among Individuals High and Low in Fitness

1996 ◽  
Vol 82 (2) ◽  
pp. 419-424 ◽  
Author(s):  
Antonios K. Travlos ◽  
Daniel Q. Marisi
Keyword(s):  
Heart Rate ◽  
Physical Exercise ◽  
Oxygen Uptake ◽  
Core Temperature ◽  
Maximal Oxygen Uptake ◽  
Perceived Exertion ◽  
Cycle Ergometer ◽  
Ratings Of Perceived Exertion ◽  
Workload Analysis ◽  
Fitness Level

This study was conducted to investigate the influence of fitness level and gradually increased amounts of exercise on individuals' ratings of perceived exertion (RPE). 20 men served as paid subjects. They were divided into groups of high (>56 ml/kg/min.) and low fitness (<46 ml/kg/min.) according to their maximal oxygen uptake (VO2 max). Participants were required to pedal on a cycle ergometer at a progressively increased workload (every 10 min.) corresponding to 40, 50, 60, 70, and 80% of individual VO2 max values. Heart rates, RPE, and core temperatures were recorded every 5th minute after the initiation of exercising at a specific workload. Analysis indicated that, when controlling for VO2 max values, elevations of heart rate and core temperature were not affected by fitness. However, highly fit individuals perceived themselves under less exertion than did the group low in fitness. Correlations showed that, taking into consideration fitness, there is a stronger relationship between RPE and heart rate and RPE and core temperature for the highly fit individuals than for the less fit.

scholarly journals Core temperature up to 41.5ºC during the UCI Road Cycling World Championships in the heat

2018 ◽  
Vol 53 (7) ◽  
pp. 426-429 ◽  
Author(s):  
Sebastien Racinais ◽  
Sebastien Moussay ◽  
David Nichols ◽  
Gavin Travers ◽  
Taoufik Belfekih ◽  
...  
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Power Output ◽  
Temperature Response ◽  
Time Trial ◽  
Ambient Conditions ◽  
Wet Bulb Globe Temperature ◽  
Road Cycling ◽  
Road Race ◽  
Globe Temperature

ObjectiveTo characterise the core temperature response and power output profile of elite male and female cyclists during the 2016 UCI Road World Championships. This may contribute to formulating environmental heat stress policies.MethodsCore temperature was recorded via an ingestible capsule in 10, 15 and 15 cyclists during the team time trial (TTT), individual time trial (ITT) and road race (RR), respectively. Power output and heart rate were extracted from individual cycling computers. Ambient conditions in direct sunlight were hot (37°C±3°C) but dry (25%±16% relative humidity), corresponding to a wet-bulb globe temperature of 27°C±2°C.ResultsCore temperature increased during all races (p<0.001), reaching higher peak values in TTT (39.8°C±0.9°C) and ITT (39.8°C±0.4°C), relative to RR (39.2°C±0.4°C, p<0.001). The highest temperature recorded was 41.5°C (TTT). Power output was significantly higher during TTT (4.7±0.3 W/kg) and ITT (4.9±0.5 W/kg) than RR (2.7±0.4 W/kg, p<0.001). Heart rate increased during the TTs (p<0.001) while power output decreased (p<0.001).Conclusion85% of the cyclists participating in the study (ie, 34 of 40) reached a core temperature of at least 39°C with 25% (ie, 10 of 40) exceeding 40°C. Higher core temperatures were reached during the time trials than the RR.

Reduced stress- and cold-induced increase in energy expenditure in interleukin-6-deficient mice

2006 ◽  
Vol 291 (3) ◽  
pp. R551-R557 ◽  
Author(s):  
Ingrid Wernstedt ◽  
Amanda Edgley ◽  
Anna Berndtsson ◽  
Jenny Fäldt ◽  
Göran Bergström ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Core Temperature ◽  
Cold Exposure ◽  
Interleukin 6 ◽  
Utilization Rate ◽  
Sympathetic Outflow ◽  
Wild Type ◽  
Deficient Mice

Interleukin-6 (IL-6) deficient (-/-) mice develop mature onset obesity. Pharmacological studies have shown that IL-6 has direct lipolytic effects and when administered centrally increases sympathetic outflow. However, the metabolic functions of endogenous IL-6 are not fully elucidated. We aimed to investigate the effect of IL-6 deficiency with respect to cold exposure and cage-switch stress, that is, situations that normally increase sympathetic outflow. Energy metabolism, core temperature, heart rate, and activity were investigated in young preobese IL-6−/− mice by indirect calorimetry together with telemetry. Baseline measurements and the effect of cage-switch stress were investigated at thermoneutrality (30°C) and at room temperature (20°C). The effect of cold exposure was investigated at 4°C. At 30°C, the basal core temperature was 0.6 ± 0.24°C lower in IL-6−/− compared with wild-type mice, whereas the oxygen consumption did not differ significantly. The respiratory exchange ratio at 20°C was significantly higher and the calculated fat utilization rate was lower in IL-6−/− mice. In response to cage-switch stress, the increase in oxygen consumption at both 30 and 20°C was lower in IL-6−/− than in wild-type mice. The increase in heart rate was lower in IL-6−/− mice at 30°C. At 4°C, both the oxygen consumption and core temperature were lower in IL-6−/− compared with wild-type mice, suggesting a lower cold-induced thermogenesis in IL-6−/− mice. The present results indicate that endogenous IL-6 is of importance for stress- and cold-induced energy expenditure in mice.

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