Jul 17, 2025Why reliable WBGT monitoring is essential for athletic heat safety protocols
Ask the Expert
(Sponsored) As heat-related illnesses become an increasing concern in athletics, the need for accurate environmental monitoring is crucial. Rebecca Stearns, chief operating officer for Korey Stringer Institute (KSI) in Storrs, Connecticut, conducts cutting-edge research for KSI, harnessing prominent expertise in heat and hydration, strength and conditioning and injury prevention — making a difference for athletes, laborers and military personnel.
Q. Can you explain the science behind WBGT and why it’s considered the gold standard for making heat safety decisions in athletics?
A. We like WBGT because it incorporates multiple environmental factors. It gives us a more global perspective of the heat stress that an individual is experiencing. It includes ambient temperature, humidity, solar radiation and can also incorporate wind speed, which are important factors in terms of how someone can thermoregulate in a warm environment.
The best practices and guidelines we have are based on WBGT, which is why we use this measurement when implementing modifications that need to be in place to optimize the health and safety of athletes and avoid heat illnesses.
Professional sports such as FIFA and the Women’s Tennis Association (WTA) have also utilized WBGT to implement safety changes and guidelines for heat stress among athletes.
Q. Your recent study compared forecasted WBGT values with on-site measurements. What were the most significant discrepancies you found?
A. The purpose of this study was to look at a device that utilized a phone app-based WBGT measure and feedback versus an on-site Kestrel WBGT Heat Stress Tracker. We also reviewed hundreds of data points in various climates across the United States.
When looking at the differences between these two devices and how you can measure on-site WBGT, it became more extreme as it got hotter — meaning the app-based device was reading a lower value compared to what was being measured on-site. On average, the two devices differed by one degree Celsius. As it got warmer, the difference between devices was two to three degrees Celsius. This has grave implications because if you’re getting a lower value, you won’t restrict physical activities as much as you should when compared to the on-site value. The app-based WBGT does not accurately reflect the modifications that need to be made for the safety of the athlete.
Q. What are some consequences of underestimating WBGT during training or competition?
A. If we underestimate WBGT, we could allow athletes to potentially wear a greater amount of equipment, have fewer rest breaks and practice longer than they should.
Q. The role of environmental data in supporting safety protocols and compliance
A. Based on regional norms, we can provide WBGT-based modifications that need to be implemented for anyone exercising in those conditions. These are specific guidelines that modify things like equipment, number of breaks, how long to practice and when to cancel. Without these guidelines and requirements, we would see athletes competing in various heat-stress levels and WBGT conditions. Our ultimate goal is to avoid exertional heat illnesses and heat stroke.
Q. What are your top 3 recommended tools or practices schools should prioritize for heat safety?
A. The data is strong for WBGT measurements and modifications on-site. This gives us some of the greatest reductions in heat illnesses, specifically in secondary school football players. We have seen reductions in heat illnesses as high as 79% if we simply modify practices based on WBGT. The Kestrel 5400 provides accurate, on-site WBGT readings by measuring all critical factors—globe temperature, humidity, wind, and solar load—in real time. It features pre-programmed heat safety zones for athletic, military, and occupational guidelines, plus alerts, data logging, and exportable reports, making it a reliable all-in-one heat stress solution.
Second, is heat acclimatization. Gradually introducing heat enables the body to adapt and develop heat tolerance. This has shown reductions in heat illnesses as much as 55%. Lastly, I would recommend having cold water immersion tubs and ice and water.
Overall, WBGT is a life-saving device that should be available to all athletes. As long as you have a plan in place and coordinate that plan with medical providers, you can execute cooling on-site before transport, which gives you the best chance of survival.
To learn more about the Kestrel 5400 WBGT Heat Stress Tracker, visit www.kestrelinstruments.com
© Kestrel 2025
