Core Body Temperature Monitoring for Better Performance in Sports

Exhausted athlete

Core body temperature is one of the four primary vital signs of our body. greenTEG offers the first solution to monitor core body temperature continuously and non-invasively. The sensor can be easily integrated into any wearable device with skin contact. Below, we explain the benefits of monitoring core body temperature in sports. Firstly, we present scientific findings on the link between core body temperature and sports performance. We then show how the ability to monitor core body temperature can help athletes perform better and longer.

In a study by Gonzalez-Alonso et al.1, athletes performing in hot environments all fatigued at a core body temperature between 40°C and 41°C, despite different initial body temperatures (Fig. 1). Previous studies observed the same results, the only difference being the core body temperature levels at which the subjects fatigued. This difference is down to the different fitness levels of the participants across the studies. A high aerobic fitness usually leads to a better heat tolerance. Some trained athletes can perform with core body temperatures exceeding the 41°C mark. 

graph showing temperature performance

The results mentioned above suggest that there is a certain critical core body temperature at which the performance of an athlete collapses. Another intriguing finding was that the time to fatigue was longer when the initial body temperature of the athlete was lower. This makes sense when considering that the core body temperature rises linearly with respect to the workload and intensity. The study concludes that a high core body temperature per se causes fatigue in athletes.

Heat-Induced Fatigue: Explanation

A physiological explanation for heat-induced fatigue is offered by Julien Périard2. Firstly, a high core body temperature causes an increased cardiovascular strain due to the additional skin blood flow required to dissipate the excessive heat. The subsequent heart rate increase can lead to the maximal heart rate being reached at lower workloads. Secondly, reaching this critical core body temperature leads to a reduction in central neural drive to the muscles. In other words, your brain stops you performing to avoid further overheating. 

Avoiding Performance Break-Down 

It becomes evident, that monitoring your cor body temperature during performances, especially in the heat, has undeniable advantages. The ability to perform just under this critical core body temperature and therefore avoid a performance breakdown is vital. Furthermore, monitoring the core body temperature during an acclimatisation program can help athletes keep their initial core body temperature low and hence prolong their time to fatigue.

González-Alonso J. et al.(1999): "Influence of body temperature on the development of fatigue during prolonged exercise in the heat", Journal of Applied Physiology Vol. 86 (3).

Périard J. (1999): "Prolonged exercise in heat", Sports Science

Périard J.: Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports

Racinais S.: Core temperature up to 41.5ºC during the UCI Road Cycling World Championships in the heat;