Athletic Heat Stress & Next Steps for Returning to Activities after COVID Shutdowns

March 2020 marked a significant change in the United States, resulting in the closure of all types of businesses ranging from restaurants to schools. With social distancing and masks recommended in public and small gatherings, organized sports took a toll from the pandemic.

Professional sports, including the NBA and MLB, postponed games. Even sports on a much smaller scale, such as little league sports, were canceled entirely. The shut-down of organized sports and activities due to Coronavirus closures eliminated the spring training season and, in many locations, has delayed the return to outdoor training this summer.

Athletes of all ages and skill levels may have experienced a setback in their conditioning due to COVID-19. This is especially true if the athlete feels he or she cannot train properly while wearing a mask around other athletes or became sedentary during the quarantine. The current environment forces some athletes to practice on their own time, and possibly not up to their typical standards or with the proper equipment.

Getting Back into the Game

In some states, gyms were one of the last businesses to open after COVID-19 restrictions were lifted. Without access to equipment and the lack of training, some athletes might struggle to get back into the game. Practices are resuming late into the season under hot conditions. De-conditioned athletes will likely be returning to training at the peak of the hot weather, with very little time for conditioning and heat acclimatization prior to organized practices resuming.

If there is a two-week period or greater of no physical activity, it's advisable to start training in accordance with the CSCCA and NSCA Joint Consensus Guidelines for Transition Periods: Safe Return to Training Following Inactivity. While these guidelines are intended for college athletes, it can be applied to high school athletes as well.

Heat stress monitoring and careful adherence to state recommendations will be critical to safeguarding teams and preventing heat illness. Ensuring athletes acclimatize to the heat gradually and build the necessary fitness to perform in hot and humid environments again will be critical to safety once practice reconvenes.

Start with Physical Evaluations

As practice resumes, regaining fitness levels while adapting to heat will be vital. Fall sports are right around the corner, and a physical evaluation can help determine where to start with training.

Requiring athletes to have a physical evaluation will ensure that the students are healthy enough to return to physical activity, and at what level or frequency.

It is critically important for any student diagnosed with or showing symptoms of COVID-19 to be evaluated by a doctor. COVID-19 is a respiratory virus, which may only exacerbate complications during heat stress. Respiratory failure during a heatwave is one of the biggest causes of mortality from athletic heat stress.

Reduce the Likelihood of Heat Stress

"Once exercise adaptations have been achieved, it is important to ensure heat acclimatization is also achieved, though these may occur simultaneously."

- Korey Stringer Institute (June 2020). Return to Sports and Exercise During the COVID-19 Pandemic: Guidance for High School and Collegiate Athletic Programs.

Heat stress in athletes occurs for several reasons, including strenuous exercise, hot environment, and clothing that does not properly wick away sweat. Inadequate adaptation or acclimatization to heat is also a significant factor in athletic heat stress.

According to the Journal of Athletic Training, onsite Wet Bulb Globe Temperatures remains a prudent choice for evaluating environmental conditions and athletic surfaces to prevent heat stress.

Monitoring WBGT and Environmental Conditions

"WBGT measurements should be taken at regular intervals on each outdoor athletic playing surface to adequately capture the environmental conditions affecting physical performance and the risk of exertional heat illness."

Journal of Athletic Training; Volume 52, Number 11, 2017

A 2017 study published in the Journal of Athletic Training shared research findings detailing the disparity between predictive measurements obtained from the National Weather Service vs. actual Wet Bulb Globe Temperature ("WBGT") measurements taken onsite above the playing surface. Relying upon National Weather Service reported WBGT readings resulted in heat-safety category misclassification across all athletic surfaces and underestimated the local heat stress, especially on dark or artificial athletic surfaces. Onsite WBGT monitoring remains the only prudent choice for determining the WBGT zone accurately in practice or play location.

The Kestrel 5400 Heat Stress Tracker is the most user-friendly WBGT meter on the market. Getting accurate measurements could not be easier – simply hold the Kestrel Heat Stress Tracker in the area of interest for instantaneous and average WBGT measurements. Set the appropriate WBGT thresholds for flag warnings, and the loud buzzer, bright LED beacon, and on-screen alerts provide instant notification of dangerous conditions.

Furthermore, with its data logger capabilities, athletic trainers can set the device to store data at specific time intervals and then send the information to their smartphones, making it easier to document, store, and share readings. Trainers can conveniently access their state's regional WBGT zones pre-loaded in the unit – allowing them to receive alerts on their mobile device when heat conditions have reached a warning zone.

In addition to WBGT, the temperature should also be monitored to prevent heat stress. The chart below gives a general overview of conditions that are safe for exercising outdoors.

The Importance of Heat Stress Monitoring with Kestrel

Accurate onsite data is crucial for identifying conditions that could be dangerous for heat illness. By monitoring the training environment with a Kestrel 5400 Heat Stress Tracker, athletic trainers can better assess the risk level and prevent or reduce heat-related illnesses.

All Kestrel 5400 models measure WBGT and all of the environmental components that contribute to heat stress -- temperature, humidity, airflow, and radiant heat. Once the recommended WBGT thresholds for warning zones are set, the loud buzzer, bright LED beacon, and on-screen warnings provide instant notification of dangerous conditions. State regional WBGT zones are also pre-loaded in the unit, and you can receive a copy of your state's guidelines when ordering direct from kestrelinstruments.com.

The 5400 Pro model adds Bluetooth Kestrel LiNK app connectivity and a wind vane tripod mount to allow for hands-free real-time monitoring and alerts on your phone (within Bluetooth range). Upload and retain data from your 5400 Pro to keep records of heat stress conditions and transfer to an iOS/Android device wirelessly with the LiNK wireless communication option and Kestrel LiNK app.

Kestrel's Heat Stress Line includes monitoring tools that every program can afford, even with budgets strained by the shut-down. You can't afford NOT to monitor heat stress, particularly this year.