Content updated as of 03/08/2026

Load management and athletic performance have reached a whole new dimension thanks to thermal physiology. In international sporting events, an athlete's ability to maintain thermal balance (homeostasis) under extreme environmental conditions is the deciding factor between stepping onto the podium or failing to finish the race.

Returning to competitive environments of extreme heat demands that medical staff and High-Performance Departments step away from intuition and adopt proactive, precise, evidence-based biological monitoring strategies.

In this context, a landmark study led by Dr. Sebastien Racinais and his team at Aspetar (alongside other international institutions), published in the British Journal of Sports Medicine, offers an unprecedented physiological roadmap. By analyzing the physiological responses of the world's best athletes during the 2019 World Athletics Championships in Doha under extreme heat conditions (32 °C and 80% relative humidity), this study demonstrates how skin temperature ($T_{sk}$) and pre-cooling are direct determinants of performance.

Below, we analyze the findings of this study and how ThermoHuman's infrared thermography technology stands out as an indispensable tool for managing thermal stress and optimizing performance in elite athletes.

The Physiological Challenge of Doha 2019: How Was the Elite Measured?

Racinais and his team aimed to characterize hydration, cooling strategies, body mass loss, and core and skin temperatures under real competition conditions. To achieve this, they evaluated 83 elite athletes (including 36 women) participating in demanding marathon and race walk events (20 km and 50 km).

The study's methodology stood out for its precision in a highly competitive field environment:

• Skin Temperature ($T_{sk}$): Measured via high-resolution thermal imaging before and after competition (after towel-drying the skin), analyzing 26 anterior and posterior regions of interest (ROIs).
• Core Temperature ($T_{core}$): Continuously recorded (one data point every 30 seconds) using ingestible capsules prior to the start of the race.
• Body Mass Loss (Dehydration): Calculated by weighing athletes immediately before the race start and right after crossing the finish line.

Skin Temperature: The Biomarker for Performance and DNF (Did Not Finish)

One of the study's most game-changing findings is the close relationship between pre-race skin temperature and athletic outcome. In high-level competition, the skin acts as a dynamic mirror of the metabolic and vascular systems, reflecting how efficiently the body dissipates heat.

The study yielded two key conclusions:

1. "The Colder, the Faster"

Among athletes who completed their events, lower pre-race skin temperature directly correlated with a better placement or faster finishing time. This lower peripheral thermal reading widens the temperature gradient between the core and the skin surface, facilitating heat dissipation during exercise.

2. The Predictor of Withdrawal (Did Not Finish - DNF)

Pre-race skin temperature was significantly higher in athletes who withdrew (DNF) compared to those who finished (an average of 33.8 °C vs. 32.6 °C).

Clinical Focus: Athletes starting competition with warmer skin are already in a state of elevated cardiovascular and thermoregulatory stress, severely limiting their capacity to tolerate subsequent exertion under extreme heat.

Elite Cooling Strategies: The Triumph of the Ice Vest

To combat thermal strain, 80% of the athletes in Doha planned a pre-cooling strategy. Among the tools evaluated, ice vests were the most common choice (used by 53%), followed by cold towels, cooling collars, and ice slushie ingestion.

Physiological results strongly supported the use of ice vests:

• Thermoregulatory Effectiveness: Athletes using ice vests significantly reduced their pre-race core temperature.
• Mitigation of Warm-Up Heating: Physical warm-ups naturally elevate core temperature. Wearing an ice vest mitigated this increase, preserving a valuable physiological buffer before the start.
• Association with Athletic Success: The average finish rank of athletes who planned to use ice vests or cold towels was noticeably superior to those who did not.
• Cooling the legs? Better not: Only 6% cooled their legs, aligning with scientific recommendations to avoid cooling propulsive muscles so as not to compromise muscle contractile capacity.

Hydration Strategies and Physiological Behaviors

The study also detailed runners' hydration behaviors and actual fluid losses:

• The Importance of Scientific Support: Although 93% of athletes had a planned hydration strategy, most relied on personal experience. However, athletes who designed their strategy alongside a sports scientist achieved significantly better final rankings.
• Moderate Body Mass Loss: Average weight loss was 2.2% of body mass, higher in the marathon (3.3%) than in the 20 km race walk (1.4%). Surprisingly, the degree of dehydration did not correlate with relative performance or DNF.
• Risk of Overhydration: Female athletes were identified as having a higher risk of overhydration and weight gain from excessive fluid intake during the event—a critical factor to monitor to avoid severe health issues like hyponatremia.

Integration with ThermoHuman Technology: From the Lab to the Field

The researchers' conclusion is unequivocal: skin temperature and its pre-competition modulation are decisive biological factors that should be routinely monitored.

This is where infrared thermography, powered by ThermoHuman's intelligent software, delivers irreplaceable strategic value for medical and technical staff:

1. Automatic Segmentation in Seconds

Manually drawing regions of interest in thermography is impractical in real competitive environments. ThermoHuman processes multiple body zones 100% automatically in seconds, reducing analysis time by over 86%. This allows an entire squad to be evaluated quickly and practically prior to exertion.

2. Precise Mapping of Thermal Signatures and Asymmetries

Every athlete has an individual thermal signature. ThermoHuman identifies significant thermal asymmetries in critical regions (such as knees, ankles, quadriceps, or hamstrings). An asymmetry greater than 0.5 °C acts as a metabolic red flag, while larger differences indicate muscle overload or inflammation that must be addressed prior to performance.

3. Objective Assessment of Pre-cooling

Our technology non-invasively and instantly monitors the success of cooling protocols. Technical staff can graphically visualize which body zones have been effectively cooled (e.g., following ice vest usage), ensuring the athlete starts competition within their optimal physiological window.

Conclusion

The Doha 2019 World Championships demonstrated that under extreme conditions, temperature management is synonymous with performance. Elite science data is irrefutable: "the colder, the faster" is a biological reality.

Integrating infrared thermography as a screening tool provides a level of physiological visibility that revolutionizes athletic preparation. Powered by ThermoHuman software, coaches, physicians, and physical therapists can customize cooling strategies and manage training/competition loads with absolute precision—bringing sports science straight to the track or pitch.

Video

https://www.youtube.com/watch?v=xi4Ut17pZrY&t=3s

References

• Racinais, S., Ihsan, M., Taylor, L., Cardinale, M., Adami, P. E., Alonso, J. M., Bouscaren, N., Buitrago, S., Esh, C. J., Gomez-Ezeiza, J., Garrandes, F., Havenith, G., Labidi, M., Lange, G., Lloyd, A., Moussay, S., Mtibaa, K., Townsend, N., Wilson, M. G., & Bermon, S. (2021). Hydration and cooling in elite athletes: relationship with performance, body mass loss and body temperatures during the Doha 2019 IAAF World Athletics Championships. British Journal of Sports Medicine, 55, 1335–1341. doi:10.1136/bjsports-2020-103613 [5, 10, 11]
• Gómez-Carmona, P., Fernández-Cuevas, I., Sillero-Quintana, M., Arnaiz-Lastras, J., & Navandar, A. (2020). Infrared Thermography Protocol on Pre-Season and In-Season in Professional Soccer to Reduce Muscle Injuries. Journal of Sport Rehabilitation, 29(8), 1011-1018. [75, 77]
• Requena-Bueno, L., Priego-Quesada, J. I., et al. (2020). Validation of ThermoHuman automatic thermographic software for assessing foot temperature before and after running. Journal of Thermal Biology, 92, 102639. [88, 89]
• Rovira-Esteve, M., Sillero-Quintana, M., Fernández-Cuevas, I., et al. (2026). Monitoring distal radius fractures during rehabilitation using infrared thermography. Frontiers in Physiology, Section in Exercise Physiology. [99, 102]