Sports performance depends not only on strength or endurance, but also on the body’s ability to regulate temperature during exertion.

In this context, infrared thermography has emerged as a non-invasive tool to observe these physiological processes in real time. Beyond skin temperature (Tsk), this technology allows for the identification of unique thermal patterns called perforasomes, known in Spanish as the Dalmatian pattern.

An article published in the European Journal of Applied Physiology analyzed how these thermal patterns are activated in cyclists and their relationship with key physiological parameters such as lactate, heart rate, and oxygen consumption (VO₂).

Study Analysis

Twenty-one cyclists performed an incremental test on a cycle ergometer until exhaustion, followed by 15 minutes of passive recovery. Lactate, heart rate, VO₂, energy expenditure, and perceived exertion were monitored. Thermography was used to track the evolution of skin temperature (Tsk) and the Thermal Contrast Index (TCI), which quantifies the difference between the warmest and coolest areas within a region of interest on the thigh.

What is the Thermal Contrast Index (TCI)?

The Thermal Contrast Index (TCI) is a parameter developed to quantify thermal heterogeneity within an anatomical region observed through infrared thermography.Instead of measuring only the mean skin temperature, the TCI calculates the difference between the warmest and coolest areas within a region of interest (for example, the thigh).Thus, the TCI reflects how the body redistributes blood flow and heat during exercise or recovery. A high TCI indicates greater thermal variability — meaning that some vascular territories are more active than others — while a low TCI suggests a more homogeneous heat distribution.

In the context of sports performance, this index is interpreted as an indirect indicator of cardiovascular and metabolic internal load, as it is closely related to the activation of perforasomes (vascular territories responsible for muscle heat dissipation).

Main Results

• The TCI increased progressively from rest to exhaustion (1.38 °C → 4.33 °C), with significant differences across most workload increments.
• After exercise, the TCI dropped rapidly, while Tsk increased during recovery.
• A negative correlation was found between Tsk and physiological parameters (r = −0.27 to −0.41), and stronger positive correlations between TCI and those same parameters (r = 0.48 to 0.72).

The Dalmatian pattern reflects the activation of vascular territories (perforasomes) that facilitate heat dissipation from muscles to the skin. Its appearance and quantification through TCI allow for a more precise identification of exercise-induced physiological changes.

What Does the Dalmatian Pattern Mean?

The Dalmatian pattern represents the activation of vascular territories (perforasomes) that enable heat dissipation from muscles toward the skin. Its emergence and quantification using TCI make it possible to detect exercise-induced physiological changes with greater accuracy.

Conclusions and Applications

This study demonstrates that the Dalmatian pattern, measured through infrared thermography, provides a more precise assessment of the body’s response to effort than Tsk alone. The TCI not only mirrors exercise intensity but also shows strong correlations with cardiovascular and metabolic parameters.

Therefore, thermography positions itself as a key tool for research and monitoring in sports performance, opening new possibilities in:

• The design of individualized training programs.
• Prevention of overtraining.
• Performance optimization in hot conditions.

Reference

Masur, L., Willenbockel, H. F., Cordes, T., Sperlich, B., & Düking, P. (2025). Detection of activated perforasome patterns and the correlation with acute internal load parameters during and following incremental cycling. European Journal of Applied Physiology, 1-12.