Estimating changes in mean body temperature for humans during exercise using core and skin temperatures is inaccurate even with a correction factor

2007 ◽  
Vol 103 (2) ◽  
pp. 443-451 ◽  
Author(s):  
Ollie Jay ◽  
Francis D. Reardon ◽  
Paul Webb ◽  
Michel B. DuCharme ◽  
Tim Ramsay ◽  
...  
Keyword(s):  
Body Temperature ◽  
Skin Temperature ◽  
Correction Factor ◽  
Estimation Error ◽  
Compartment Model ◽  
Traditional Model ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Two Compartment Model ◽  
Adjusted Model

Changes in mean body temperature (ΔT̄b) estimated by the traditional two-compartment model of “core” and “shell” temperatures and an adjusted two-compartment model incorporating a correction factor were compared with values derived by whole body calorimetry. Sixty participants (31 men, 29 women) cycled at 40% of peak O2 consumption for 60 or 90 min in the Snellen calorimeter at 24 or 30°C. The core compartment was represented by esophageal, rectal (Tre), and aural canal temperature, and the shell compartment was represented by a 12-point mean skin temperature (T̄sk). Using Tre and conventional core-to-shell weightings ( X) of 0.66, 0.79, and 0.90, mean ΔT̄b estimation error (with 95% confidence interval limits in parentheses) for the traditional model was −95.2% (−83.0, −107.3) to −76.6% (−72.8, −80.5) after 10 min and −47.2% (−40.9, −53.5) to −22.6% (−14.5, −30.7) after 90 min. Using Tre, X = 0.80, and a correction factor ( X0) of 0.40, mean ΔT̄b estimation error for the adjusted model was +9.5% (+16.9, +2.1) to −0.3% (+11.9, −12.5) after 10 min and +15.0% (+27.2, +2.8) to −13.7% (−4.2, −23.3) after 90 min. Quadratic analyses of calorimetry ΔT̄b data was subsequently used to derive best-fitting values of X for both models and X0 for the adjusted model for each measure of core temperature. The most accurate model at any time point or condition only accounted for 20% of the variation observed in ΔT̄b for the traditional model and 56% for the adjusted model. In conclusion, throughout exercise the estimation of ΔT̄b using any measure of core temperature together with mean skin temperature irrespective of weighting is inaccurate even with a correction factor customized for the specific conditions.

scholarly journals Effect of food intake on the ventilatory response to increasing core temperature during exercise

2019 ◽  
Vol 44 (1) ◽  
pp. 22-30 ◽  
Author(s):  
Keiji Hayashi ◽  
Nozomi Ito ◽  
Yoko Ichikawa ◽  
Yuichi Suzuki
Keyword(s):  
Food Intake ◽  
Body Temperature ◽  
Skin Temperature ◽  
Core Temperature ◽  
Mean Skin Temperature ◽  
Carbon Dioxide Elimination ◽  
Transient Effect ◽  
Mean Body Temperature ◽  
Ventilatory Parameters ◽  
Effect Of Food

Food intake increases metabolism and body temperature, which may in turn influence ventilatory responses. Our aim was to assess the effect of food intake on ventilatory sensitivity to rising core temperature during exercise. Nine healthy male subjects exercised on a cycle ergometer at 50% of peak oxygen uptake in sessions with and without prior food intake. Ventilatory sensitivity to rising core temperature was defined by the slopes of regression lines relating ventilatory parameters to core temperature. Mean skin temperature, mean body temperature (calculated from esophageal temperature and mean skin temperature), oxygen uptake, carbon dioxide elimination, minute ventilation, alveolar ventilation, and tidal volume (VT) were all significantly higher at baseline in sessions with food intake than without food intake. During exercise, esophageal temperature, mean skin temperature, mean body temperature, carbon dioxide elimination, and end-tidal CO2 pressure were all significantly higher in sessions with food intake than without it. By contrast, ventilatory parameters did not differ between sessions with and without food intake, with the exception of VT during the first 5 min of exercise. The ventilatory sensitivities to rising core temperature also did not differ, with the exception of an early transient effect on VT. Food intake increases body temperature before and during exercise. Other than during the first 5 min of exercise, food intake does not affect ventilatory parameters during exercise, despite elevation of both body temperature and metabolism. Thus, with the exception of an early transient effect on VT, ventilatory sensitivity to rising core temperature is not affected by food intake.

Estimating changes in volume-weighted mean body temperature using thermometry with an individualized correction factor

2010 ◽  
Vol 299 (2) ◽  
pp. R387-R394 ◽  
Author(s):  
Ollie Jay ◽  
Michel B. DuCharme ◽  
Paul Webb ◽  
Francis D. Reardon ◽  
Glen P. Kenny
Keyword(s):  
Body Temperature ◽  
Skin Temperature ◽  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
Estimation Error ◽  
Core Shell ◽  
Weighted Mean ◽  
Mean Body Temperature ◽  
C 30

This study investigated whether the estimation error of volume-weighted mean body temperature (ΔT̄b) using changes in core and skin temperature can be accounted for using personal and environmental parameters. Whole body calorimetry was used to directly measure ΔT̄b in an Experimental group (EG) of 36 participants (24 males, 12 females) and a Validation group (VG) of 20 (9 males, 11 females) throughout 90 min of cycle ergometry at 40°C, 30% relative humidity (RH) ( n = 9 EG, 5 VG); 30°C, 30% RH ( n = 9 EG, 5 VG); 30°C, 60% RH ( n = 9 EG, 5 VG); and 24°C, 30% RH ( n = 9 EG, 5 VG). The core of the two-compartment thermometry model was represented by rectal temperature and the shell by a 12-point mean skin temperature (ΔT̄sk). The estimation error (X0) between ΔT̄b from calorimetry and ΔT̄b from thermometry using core/shell weightings of 0.66/0.34, 0.79/0.21, and 0.90/0.10 was calculated after 30, 60, and 90 min of exercise, respectively. The association between X0 and the individual variation in metabolic heat production (M − W), body surface area (BSA), body fat percentage (%fat), and body surface area-to-mass ratio (BSA/BM) as well as differences in environmental conditions (Oxford index) in the EG data were assessed using stepwise linear regression. At all time points and with all core/shell weightings tested, M − W, BSA, and Oxford index independently correlated significantly with the residual variance in X0, but %fat and BSA/BM did not. The subsequent regression models were used to predict the thermometric estimation error (X0_pred) for each individual in the VG. The value estimated for X0_pred was then added to the ΔT̄b estimated using the two-compartment thermometry models yielding an adjusted estimation (ΔT̄b_adj) for the individuals in the VG. When comparing ΔT̄b_adj to the ΔT̄b derived from calorimetry in the VG, the best performing model used a core/shell weighting of 0.66/0.34 describing 74%, 84%, and 82% of the variation observed in ΔT̄b from calorimetry after 30, 60, and 90 min, respectively.

The effect of hand immersion on body temperature when wearing impermeable clothing

1991 ◽  
Vol 77 (1) ◽  
pp. 41-47
Author(s):  
A. J. Allsopp ◽  
Kerry A. Poole
Keyword(s):  
Body Temperature ◽  
Skin Temperature ◽  
Environmental Temperature ◽  
List Type ◽  
Physiological Measures ◽  
Total Work ◽  
Mean Skin Temperature ◽  
Work Time ◽  
Experimental Conditions ◽  
Rest Periods

AbstractThe effects of hand immersion on body temperature have been investigated in men wearing impermeable NBC clothing. Six men worked continuously at a rate of approximately 490 J.sec−1 in an environmental temperature of 30°C. Each subject was permitted to rest for a period of 20 minutes when their aural temperature reached 37.5°C, and again on reaching 38°C, and for a third time on reaching 38.5°C (three rest periods in total). Each subject completed three experimental conditions whereby, during the rest periods they either: a.Did not immerse their hands (control).b.Immersed both hands in a water bath set at 25°c.c.Immersed both hands in water at 10°C.Physiological measures of core temperature, skin temperature and heart rate were recorded at intervals throughout the experiment.Measures of mean aural temperature and mean skin temperature were significantly (P<0.05) reduced if hands were immersed during these rest periods, compared to non immersion. As a result, the total work time of subjects was extended when in the immersed conditions by some 10–20 minutes within the confines of the protocol.It is concluded that this technique of simple hand immersion may be effective in reducing heat stress where normal routes to heat loss are compromised.

scholarly journals Improved 2000-m Rowing Performance in a Cool Environment With an External Heating Garment

2021 ◽  
Vol 16 (1) ◽  
pp. 103-109
Author(s):  
Gavin Cowper ◽  
Martin Barwood ◽  
Stuart Goodall
Keyword(s):  
Body Temperature ◽  
Skin Temperature ◽  
Core Body Temperature ◽  
Time Trial ◽  
Mean Skin Temperature ◽  
Warm Up ◽  
External Heating ◽  
Rowing Performance ◽  
Cool Environment ◽  
Core Body

Purpose: Rowers can be in marshaling areas for up to 20 to 25 min before the start of a race, which likely negates any benefits of an active warm-up, especially in cold environments. It is unknown if using a heated jacket following a standardized rowing warm-up can improve 2000-m rowing performance. Methods: On 2 separate occasions, 10 trained male rowers completed a standardized rowing warm-up, followed by 25 min of passive rest before a 2000-m rowing time trial on a rowing ergometer. Throughout the passive rest, the participants wore either a standardized tracksuit top (CON) or an externally heated jacket (HEAT). The trials, presented in a randomized crossover fashion, were performed in a controlled environment (temperature 8°C, humidity 50%). Rowing time-trial performance, core body temperature, and mean skin temperature, along with perceptual variables, were measured. Results: During the 25-min period, core body temperature increased in HEAT and decreased in CON (Δ0.54°C [0.74°C] vs −0.93°C [1.14°C]; P = .02). Additionally, mean skin temperature (30.22°C [1.03°C] vs 28.86°C [1.07°C]) was higher in HEAT versus CON (P < .01). In line with the physiological data, the perceptual data confirmed that participants were more comfortable in HEAT versus CON, and subsequently, rowing performance was improved in HEAT compared with CON (433.1 [12.7] s vs 437.9 [14.4] s, P < .01). Conclusion: The data demonstrate that an upper-body external heating garment worn following a warm-up can improve rowing performance in a cool environment.

Effect of O2 affinity on arterial PO2 in animals with central vascular shunts

1982 ◽  
Vol 53 (6) ◽  
pp. 1360-1364 ◽  
Author(s):  
S. C. Wood
Keyword(s):  
Body Temperature ◽  
Compartment Model ◽  
Congenital Defects ◽  
Arterial Blood ◽  
Venous Shunt ◽  
Two Compartment Model ◽  
Ectothermic Vertebrate ◽  
The Right ◽  
Dissociation Curves

Central vascular or intracardiac shunts result in venous admixture and reduced saturation of systemic arterial blood. This is pronounced in most species of amphibians and reptiles and may occur as congenital defects in homeotherms. A two-compartment model is useful to analyze the effects of shunt on O2 transport. The PO2 of a mixture of pulmonary (ideal) and mixed venous (shunt) blood will be a function of the resulting O2 saturation, analogous to the principle of the “mixing method” in vitro. Furthermore, for a given saturation, the PO2 of systemic arterial blood (PaO2) should be inversely related to the O2 affinity of the mixed blood. The present study tested this two-compartment model of shunt in animals with normally occurring right-to-left shunts (amphibians and reptiles) and with dogs having artificial shunts. The O2 dissociation curves (ODC) of the blood were manipulated by varying body temperature and blood pH. For any level of saturation of systemic arterial blood, the PaO2 was found to increase with factors that shifted the ODC to the right. This experimental support of mathematical models of shunting and PaO2 suggests that animals with intracardiac or central vascular shunts are benefited by low-O2-affinity blood, a condition that is common in amphibians and reptiles. For an individual ectothermic vertebrate, an increase in O2 demand due to increased body temperature would, because of decreased O2 affinity, be accompanied and perhaps facilitated by an increase in PaO2 if saturation remained constant.

A three-compartment thermometry model for the improved estimation of changes in body heat content

2007 ◽  
Vol 292 (1) ◽  
pp. R167-R175 ◽  
Author(s):  
Ollie Jay ◽  
Louise M. Gariépy ◽  
Francis D. Reardon ◽  
Paul Webb ◽  
Michel B. Ducharme ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Estimation Error ◽  
Heat Content ◽  
Compartment Model ◽  
Whole Body ◽  
Moderate Intensity ◽  
Upper Trapezius ◽  
Two Compartment Model ◽  
Three Compartment Model ◽  
Body Heat

The aim of this study was to use whole body calorimetry to directly measure the change in body heat content (ΔHb) during steady-state exercise and compare these values with those estimated using thermometry. The thermometry models tested were the traditional two-compartment model of “core” and “shell” temperatures, and a three-compartment model of “core,” “muscle,” and “shell” temperatures; with individual compartments within each model weighted for their relative influence upon ΔHb by coefficients subject to a nonnegative and a sum-to-one constraint. Fifty-two participants performed 90 min of moderate-intensity exercise (40% of V̇o2 peak) on a cycle ergometer in the Snellen air calorimeter, at regulated air temperatures of 24°C or 30°C and a relative humidity of either 30% or 60%. The “core” compartment was represented by temperatures measured in the esophagus (Tes), rectum (Tre), and aural canal (Tau), while the “muscle” compartment was represented by regional muscle temperature measured in the vastus lateralis (Tvl), triceps brachii (Ttb), and upper trapezius (Tut). The “shell” compartment was represented by the weighted mean of 12 skin temperatures (T̄sk). The whole body calorimetry data were used to derive optimally fitting two- and three-compartment thermometry models. The traditional two-compartment model was found to be statistically biased, systematically underestimating ΔHb by 15.5% (SD 31.3) at 24°C and by 35.5% (SD 21.9) at 30°C. The three-compartment model showed no such bias, yielding a more precise estimate of ΔHb as evidenced by a mean estimation error of 1.1% (SD 29.5) at 24°C and 5.4% (SD 30.0) at 30°C with an adjusted R2 of 0.48 and 0.51, respectively. It is concluded that a major source of error in the estimation of ΔHb using the traditional two-compartment thermometry model is the lack of an expression independently representing the heat storage in muscle during exercise.

Safety and health risks for workers exposed to cold thermal environments: A frozen food processing industry perspective

Work ◽  
2021 ◽  
pp. 1-11
Author(s):  
Tomi Zlatar ◽  
Béda Barkokébas Junior ◽  
Laura Martins Bezerra ◽  
Margarida Maria Araujo Brito ◽  
José Torres Costa ◽  
...  
Keyword(s):  
Skin Temperature ◽  
Food Industry ◽  
Thermal Sensation ◽  
Cold Work ◽  
Health And Safety ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Frozen Food ◽  
Thermal Environments ◽  
Fresh Food

BACKGROUND: Environmental temperatures in the fresh food industry vary from 0°C to 10°C, and go below -20°C for the frozen food industry, representing risk for the health and safety of workers involved. OBJECTIVE: The aim of this work was to evaluate the cold thermal stress risks for workers working in a frozen food industry. METHODS: A total of 27 acclimatized workers (13 male and 14 female) participated in a study which was conducted during 11 working days. The thermal sensation questionnaire and the cold work health questionnaire (CWHQ) were applied to all participants. Additionally, 4 workers were chosen to be fully monitored with a thermometer telemetry capsule for measuring the intra-abdominal temperature and 8 skin temperature sensors. RESULTS: The lowest recorded hand temperature was 14.09°C, lowest forehead 18.55°C, mean skin temperature had variations of 1.10 to 3.20°C along the working period. Highest and most frequent fluctuations were found in the hand and forehead skin temperatures, small changes were found in mean skin temperature. CONCLUSIONS: Answers to the CWHQ increase concern on clinical forms of “a frigore”, and in two cases the mean body temperature decreased below 35.0°C, which is defined in the current literature as a mild form of hypothermia.

Variable open-loop gain in the control of thermogenesis in cold-exposed rabbits

1980 ◽  
Vol 48 (3) ◽  
pp. 495-499 ◽  
Author(s):  
J. T. Stitt
Keyword(s):  
Steady State ◽  
Body Temperature ◽  
Skin Temperature ◽  
Rectal Temperature ◽  
Open Loop ◽  
Loop Gain ◽  
Mean Skin Temperature ◽  
Hypothalamic Temperature ◽  
Multiplicative Interaction ◽  
Ambient Temperatures

We have previously demonstrated a multiplicative interaction between mean skin temperature (Tsk) and hypothalamic temperature (Thy) in the control of thermogenesis in cold exposed rabbits. Such a model predicts that open-loop gain will not be constant, but will vary according to the direction and degree of Thy displacements and to the prevailing level of Tsk when Thy is altered. Open-loop gain was calculated from steady-state displacements in body temperature induced by sustained step displacements in Thy. Hypothalamic temperature of rabbits was clamped at various levels ranging from 2 degrees C above to 3 degrees C below normal Thy and the resulting changes in rectal temperature attained at steady state were recorded. Experiments were conducted at ambient temperatures (Ta) of 2 degrees and 15 degrees C. Open-loop gain in response to hypothalamic heating was always greater than that obtained in response to equivalent levels of hypothalamic cooling. Furthermore, at lower levels of Tsk (Ta = 2 degrees C) open-loop gain was greater for all levels of Thy displacement when compared to that measured at higher levels of Tsk (Ta = 15 degrees C).

Day–night variation of thermoregulatory responses of heifers exposed to high environmental temperatures

1997 ◽  
Vol 129 (2) ◽  
pp. 199-204 ◽  
Author(s):  
C. M. MUNDIA ◽  
S. YAMAMOTO
Keyword(s):  
Skin Temperature ◽  
Respiration Rate ◽  
Heat Balance ◽  
Thermal Sensitivity ◽  
Skin Surface ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Rate Of Increase ◽  
Vaginal Temperature ◽  
Environmental Temperatures

In order to assess relative thermal sensitivity between the day and the night, vaginal temperature (Tv), heat production (HP), heart rate (HR), respiration rate (RR), skin surface temperatures (from which mean skin temperature (Ts) was calculated) and standing time were measured at environmental temperatures (Te) of 23, 28, 33 and 38°C during the day (11.00–15.00 h) and during the night (23.00–03.00 h) using four Holstein heifers. Both Tv and mean body temperature (Tb) were greater during the night than during the day, increased with increased Te, and the rate of increase of both Tv and Tb with increased Te was greater during the night (P<0·05). Estimated mean HP was similar during the night and during the day, and HP did not increase with increased Te. Respiration rate was greater but not significantly different at night compared to during the day, and increased with increased Te. Mean skin temperature was similar between day and night, and increased with increased Te. The amount of time engaged in standing activity was greater but not significantly different during the night than during the day and standing activity increased with increased Te. The results suggest that thermal sensitivity is lower during the night than during the day, and consequently the greater night responses of Tv and Tb, over day responses, are a requirement for the maintenance of heat balance.

Treatment of myxoedema coma factors associated with fatal outcome

1985 ◽  
Vol 108 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Britta Hylander ◽  
Urban Rosenqvist
Keyword(s):  
Heart Rate ◽  
Retrospective Study ◽  
Body Temperature ◽  
Causes Of Death ◽  
Fatal Outcome ◽  
Compartment Model ◽  
High Serum ◽  
High Serum Level ◽  
Factors Associated ◽  
Two Compartment Model

Abstract. Treatment of myxoedema coma has been associated with a high mortality. The causes of death were analysed in this paper by retrospective study of the records of 11 myxoedema coma patients. The serum thyroxine (T4) and triiodothyronine (T3) levels were estimated retrospectively from the amounts of hormone given to the patients by a two-compartment model. Seven patients died and 4 survived. The patients who died were significantly older (78.9 ± 2.2 years, mean ± sem) than those who survived (66.8 ± 3.7 years). The initial heart rate was lower in the deceased group, but both groups had increased their heart rate on treatment. The surviving patients showed an increase in body temperature during the first 3 days of treatment, in contrast to the patients who eventually died. The deceased patients had received larger amounts of thyroid hormone and had calculated levels of T3 that were nearly twice as high as those of the surviving patients. Old age and a high serum level of T3 are determinants for the fatal outcome of myxoedema coma. Our analysis underscores the importance of using a cautious replacement regimen in myxoedema coma patients.

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