Evaluation and Validity of a Predictive Equation for Measuring Core Temperature during Exercise in Heat Stress

Authors

Robert J. Castro, San Diego State UniversityFollow
Alexander J. Gonsalves, San Diego State UniversityFollow
Edgar B. Doolan, San Diego State UniversityFollow
Jochen Kressler, San Diego State UniversityFollow

Abstract

Exercising in the heat is very common yet can pose significant health risks such as heat exhaustion and heat stroke when core temperature exceeds 38°C and 40°C, respectively. However, current methods of core temperature measurement are invasive and impractical. Recent research indicates that core temperature can be predicted with two non-invasive inputs, heart rate (HR) and skin temperature. PURPOSE: The objective of this study was to assess the validity and reliability of this predictive equation against the direct measurement of core temperature. METHODS: Participants (n = 11) cycled in an environmental chamber (40°C, 40% humidity) at 75% of maximal HR for 45 minutes. Measurements included HR, scapular skin and core temperature, blood pressure, and rating of perceived exertion. Exercise stopped if core temperature exceeded 38.5°C for two consecutive measurements or volitional fatigue. Agreement between predicted and actual core temperature was assessed with Bland–Altman analysis. RESULTS: There was a low correlation (r² = 0.2) between the direct measure and predicted core temperatures. The Bland–Altman analysis for core minus predicted temperatures showed a bias of 0.14°C and limits of agreement ranging from 0.72°C to −0.45°C. In addition, a large proportion of measurements (40.5%) of the total scores had a difference in temperature greater than ±0.3°C. The predictive equation overpredicted as mean temperature increased from the average core temperature (37°C). CONCLUSION: Based on the narrow temperature range the human body must stay within to prevent heat-related issues, we’ve concluded that the predictive equation lacks sufficient validity and reliability.

Recommended Citation

Castro, Robert J.; Gonsalves, Alexander J.; Doolan, Edgar B.; and Kressler, Jochen (2022) "Evaluation and Validity of a Predictive Equation for Measuring Core Temperature during Exercise in Heat Stress," International Journal of Exercise Science: Conference Proceedings: Vol. 14: Iss. 2, Article 110.
Available at: https://digitalcommons.wku.edu/ijesab/vol14/iss2/110