ORIGINAL RESEARCH article
Front. Physiol.
Sec. Exercise Physiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1631729
This article is part of the Research TopicAssessment and Monitoring of Human Movement Volume IIView all 3 articles
Dynamic Correlation Between Chest Temperature Entropy and Physiological Load Indicators, and Excess Post-Exercise Oxygen Consumption During Incremental Cycling Exercise
Provisionally accepted
- 1Department of Orthopedics, Fourth Medical Center of PLA General Hospital, Beijing, China
- 2Beijing Sport University, Beijing, China
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This study explores the dynamic relationship between chest region temperature entropy and physiological load indicators, as well as excess post-exercise oxygen consumption (EPOC), during incremental cycling exercise, using high-sampling-rate infrared thermography (IRT). In this context, entropy refers to the complexity or disorder of the spatial distribution of temperature. Twenty-four healthy young male participants (age 23.7 ± 3.3 years, height of 178.6 ± 9.8 cm, weight 78.5 ± 6.4 kg, training duration 237.8±48.7 min/week, maximal oxygen uptake 44.06±5.9 ml/kg/min, and maximal power output 263.8±27.4 watts) completed an incremental cycling test starting at a 60W workload, increasing by 30w every 2 minutes. Chest thermography, oxygen consumption (VO₂), blood lactate, and external load (watt) data were simultaneously collected, with entropy used to quantify the complexity of temperature distribution. The results show significant non-linear positive correlations between the standardized percentage increase in chest temperature entropy and VO₂ (R²=0.809), blood lactate (R ² =0.719), and external load (R ² =0.841). Further individual-level analysis reveals significant positive correlations between entropy increase percentage and VO₂ (r=0.874–0.977), blood lactate (r=0.692–0.989), and external load (r=0.889–0.986) (p<0.05). Three-dimensional hierarchical clustering analysis identified three clusters based on temperature entropy, VO ₂ , and blood lactate, corresponding to low, moderate, and high metabolic load states. During the EPOC phase, a significant association was observed between temperature entropy and recovery metabolism (R ² =0.151), with further individual analysis revealing heterogeneity in the relationship (r=-0.288 to 0.907). This study confirms that chest temperature entropy dynamically reflects the energy metabolism characteristics and load variations under incremental load, providing a new perspective for non-invasive monitoring of exercise load and recovery progress.
Keywords: thermal imaging, Entropy analysis, Incremental Exercise Protocol, Oxygen Consumption, Blood lactate response
Received: 20 May 2025; Accepted: 28 Aug 2025.
Copyright: © 2025 Cui, Du, Liu and Hu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Chenxi Hu, Beijing Sport University, Beijing, China
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