An improved estimation of mean body temperature using combined direct calorimetry and thermometry

Snellen, J. W.

doi:10.1007/s004210050671

Cited by 28 publications

(15 citation statements)

References 10 publications

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“…However, the present study, with the exception of Snellen (38), is the first to use whole body direct air calorimetry to assess such a concept. Nadel et al (28) where T es is esophageal temperature; T m is quadriceps temperature, and T sk is mean skin temperature.…”

Section: Discussionmentioning

confidence: 95%

“…Previous research has shown that the two-compartmental thermometry model greatly underestimates ⌬T b and therefore ⌬H b (15,18,38,43). Despite this, the two-compartment model is still extensively used for the estimation of ⌬T b and ⌬H b , both as an analytical tool for assessing individual heat load status for a wide range of subpopulations (1,7,36,49) and extensively as a physiological criterion for maximal heat exposure (2,16,17,19,22).…”

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confidence: 99%

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

Jay¹,

Gariépy²,

Reardon³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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Jay, O, Gariépy LM, Reardon FD, Webb P, Ducharme MB, Ramsay T, Kenny GP. A three-compartment thermometry model for the improved estimation of changes in body heat content. Am J Physiol Regul Integr Comp Physiol 292: R167-R175, 2007. First published August 24, 2006; doi:10.1152/ajpregu.00338.2006.-The aim of this study was to use whole body calorimetry to directly measure the change in body heat content (⌬Hb) during steady-state exercise and compare these values with those estimated using thermometry. The thermometry models tested were the traditional twocompartment model of "core" and "shell" temperatures, and a threecompartment model of "core," "muscle," and "shell" temperatures; with individual compartments within each model weighted for their relative influence upon ⌬Hb by coefficients subject to a nonnegative and a sum-to-one constraint. Fifty-two participants performed 90 min of moderate-intensity exercise (40% of V O2 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 (T sk). 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 ⌬Hb 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 ⌬Hb 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 R 2 of 0.48 and 0.51, respectively. It is concluded that a major source of error in the estimation of ⌬Hb using the traditional two-compartment thermometry model is the lack of an expression independently representing the heat storage in muscle during exercise. body heat storage; calorimetry; muscle temperature; thermoregulation THE DERIVATION OF THE CHANGE in body heat content (⌬H b ) is of fundamental importance to the physiologist assessing the exposure of the human body to environmental conditions that result in thermal imbalance. In theory, the measurement of body heat exchange using simultaneous measures of direct and indirect calorimetry is the only method whereby ⌬H b can be directly determined. Thus the difference between metabolic heat production using the stoichiometric relationship of the products and reactants of oxidative metabolism (indirect calorimetry) and the total heat lost from the body can be used to estimate ⌬H b . By definition, ⌬H b is the product of the change of the mean temperature of the tissues of the body (⌬T b ), the total body mass (b m ), and the average sp...

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Section: Discussionmentioning

confidence: 95%

mentioning

confidence: 99%

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

Jay¹,

Gariépy²,

Reardon³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Modified from Kenny et al (2008) and used with permission. approach can result in significant underestimations of heat storage (Vallerand et al, 1992b;Snellen, 2000;Jay et al, 2007aJay et al, , 2007bSawka and Castellani, 2007). Comparisons using direct calorimetry showed those errors increased when moderate intensity exercise ( $ 40% maximal aerobic power) was performed in warmer conditions (i.e.…”

Section: Partitional Calorimetry Thermometry and Mean Body Temperaturementioning

confidence: 97%

Considerations for the measurement of core, skin and mean body temperatures

Taylor

Tipton

Kenny

2014

Journal of Thermal Biology

336

243

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“…Alternative coefficients have also been suggested for differing levels of clothing insulation (Aoyagi et al, 1996a(Aoyagi et al, , 1996b. However irrespective of the selected weighting coefficients several studies Horstman and Horvath, 1972;Snellen, 2000;Vallerand et al, 1992) have demonstrated that the two-compartmental thermometry model significantly underestimates DT ළ b and therefore DH b by up to ϳ35% (Jay et al, 2007). The thermometry approach is also limited to steady-state body temperatures both at rest and during exercise.…”

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The Determination of Changes in Body Heat Content during Exercise Using Calorimetry and Thermometry

Jay

Kenny

2007

JHES

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Following the onset of exercise there is a sudden increase in metabolic heat production that cannot be initially offset by the body's heat loss mechanisms. During this thermal imbalance a change in body heat content (DH b ) occurs. The only way the value for DH b can be truly determined is by performing simultaneous direct measurements of the rates of heat production and heat loss. There are several calorimetric methods that can be used to quantify these values. The most accurate and simple method for measuring the rate of heat production is by separately calculating the energy released from the oxidation of fats and carbohydrates using indirect calorimetry, while direct air flow calorimetry provides the most accurate and responsive measurement of total body heat loss. Thermometry is often used as a surrogate for calorimetry by estimating mean body temperature and subsequently deriving a value for DH b . The most common thermometry approach, the 2-compartment model of "core" and "shell" temperature, has been demonstrated to greatly underestimate DH b . The inclusion of a third compartment representing the thermal influences of muscle tissue has been demonstrated to provide a better thermometric estimation of DH b ; however this requires the invasive measurement of intramuscular temperature. A modified 2-compartment thermometry model incorporating an "adjustment factor" correcting for the underestimation of the traditional model for DH b appears to be the most practical alternative. Further research is required to develop thermometry model for the better estimation of DH b under various conditions.

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An improved estimation of mean body temperature using combined direct calorimetry and thermometry

Cited by 28 publications

References 10 publications

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

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

Considerations for the measurement of core, skin and mean body temperatures

The Determination of Changes in Body Heat Content during Exercise Using Calorimetry and Thermometry

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