Beat the Heat: Signs, Symptoms and Ways to Prevent Exertional Heat Illness

Every year, athletes of all different sports practice, exercise, or train outside through the summer months. This high volume of aspiring and hopeful athletes training in intense temperatures can lead to disaster if people supervising the activities are not adequately prepared to identify and address signs and symptoms of possible Exertional Heat Illness (EHI).

Exertional Heat Illness is the leading cause of death in highschool athletes, according to the CDC. Exertional Heat Illness is something that can be avoided if coaches, trainers, parents, and everyone involved in the sports community are aware of the signs/symptoms.

It is estimated that over 9,000 high school athletes are treated annually for Exertional Heat Illness. Currently in the U.S., there are more than 8 million high school athletes, and over 480,000 NCAA athletes. This is a significant number of athletes in the United States, and with the general trajectory of warming temperatures that is occurring around the globe, it is critical that we as a sports community know how to best protect and keep our athletes safe and prevent these avoidable, tragic incidents (1).

It is not only up to the coaches but instead should be a group effort. If the athletes, their parents, athletic trainers, physical therapists, and other medical providers are able to identify the warning signs of Exertional Heat Illness, then we as a sports community will be better equipped to allow our athletes to safely perform at their highest level. 

What is Heat Related Illness / Injury?

So what is Exertional Heat Illness, and the stages that lead up to Exertional Heat Stroke? To best sum it up, Exertional Heat Illness is your body’s response to exercise intensity, duration, and temperature that cause the body to not be able to maintain a normal core temperature (98.6 ℉). One of the first possible signs of Exertional Heat Illness is exercise associated muscle cramps. 

1. Exercise associated muscle cramps- most commonly known as tics, twinges, stiffness, contractures, or tremors. Heat is not necessarily required for these to occur, but some hypothesized factors for cramps occurring include dehydration, fatigue, altered neuromuscular control, and/or an electrolyte imbalance. 

2.  Heat Syncope - a technical way to describe dizziness that often occurs in the first 5 days of training outside while the athlete is unaccustomed to the heat exposure. This stage results in dizziness and possibly passing out with a change of position typically from sitting or bending over, to standing up straight.

3. Heat Exhaustion - “the inability to effectively exercise in the heat secondary to a combination of factors including cardiovascular insufficiency, hypotension, energy depletion, and central fatigue” (nata paper). Some signs and symptoms are as follows:

   • Elevated core body temperature (from 98.6℉-104℉)

   • Whole body weakness

   • Fatigue and possible collapse (athlete typically remains conscious)

   • Significant fluid volume loss (from excessive sweating / dehydration)

4. Exertional Heat Injury- athlete exhibits signs and symptoms of heat exhaustion, but their core temperature is > 105℉. This is the final step before an athlete with experience Exertional Heat Stroke which can result in the following: 

   • Kidney Damage

   • Liver damage 

   • Gastrointestinal distress (leaky gut)- a systemic inflammatory response which can result in bacteria entering the circulatory system resulting in multi-organ failure if left untreated
     Exertional Heat Injury’s primary distinction from Exertional Heat Stroke is that there is no neuropsychiatric involvement with Exertional Heat Exhaustion

5. Exertional Heat Stroke - all of the signs and symptoms of Exertional Heat Injury, but there are neuropsychiatric symptoms such as : 

   • Mood change for the athlete 

   • Irritable 

   • Angry 

   • Combative 

   • Bizarre behavior 

   • Collapsed athlete 

   • Confusion 

   *If there is an athlete who collapses, it should be treated as if they are suffering from Exertional Heat Stroke until an accurate rectal core temperature is taken. 

What to do if Your Athlete is Suffering from Exertional Heat Illness

If the athlete is responsive / cooperative (core temperature not over 105℉)-

1. Immediately cool core temperature- an ice bath results in the most rapid cooling of core temperature

2. If an ice bath is not available consider using fans, wet towels, ice, and/or tents/trees for shade should be used. Cold towels / ice should be placed on the neck, armpits, and groin areas.

If the athlete is unresponsive / collapsed-

1. Insert rectal thermometer for core temperature monitoring

2. Remove excessive clothes / pads

3. Ice water immersion- this athlete needs rapid cooling until EMS arrives 

4. Per the National Athletic Training Association (NATA), the athlete should not be transported to the hospital until their core temperature gets down to 102℉.

How Can this be Avoided ? 

Exertional heat illness can be prevented if sports teams and athletes ensure they are properly acclimated to high temperatures prior to high intensity training in higher, humid temperatures. Exertional Heat Illness often occurs in preseasons, meaning that athletes should have a proper “ramp-up” period of activity to ensure athlete safety. What does a proper “ramp-up” period look like? 

1. Limit use of pads / protective equipment initially

2. Ensure frequent water breaks to allow for athlete core temperature, heart rate, sweat rate, and hydration to improve/increase 

Who is More at Risk of Suffering from Exertional Heat Illness?

Below is a list a risk factors that we as athletes, medical providers, coaches, and trainers can be aware of to potentially decrease the risk of Exertional Heat Illness.

1. Environmental Factors - (things we can directly impact)

   • Not long enough rest or breaks

   • Lack of shelter / shade

   • High humidity

   • High temperatures

   • Inadequate access to water

2. Individual Risk Factors

   • Younger than 15 or older than 65 years old

   • Deconditioning or sedentary lifestyle

   • Excessive clothing

   • Inadequate sleep

   • Lack of acclimation

   • Male sex

   • Obesity

   • Dehydration

3. Medical Risk Factors

   • Heart disease

   • Diabetes Mellitus

   • Previous heat injury

   • Recent illness

   • Sickle Cell trait

Activity Guidelines for Athletes

Activity guidelines regarding break times and practice length during sport are specific to regions within the U.S. New Jersey, Delaware, and easter Pennsylvania are considered Category 2 states which are determined based on Wet Bulb Globe Temperature extremes to the region. So for the figure below which has come from the Korey Stinger Institute, New Jersey falls into the Category 2 column for athletes training outdoors. If you are in a different region of the United States, you can use this  Grundstein et al. Regional heat safety thresholds for athletes in the contiguous United States. Appl. Geography. 2015.pdf. To find the activity guidelines for your specific area! 

By: Dr. John Vizzini

Sources:

1. https://www.ncaa.org/sports/2015/3/2/estimated-probability-of-competing-in-college-athletics.aspx#:~:text=Nearly%20eight%20million%20students%20currently,the%20professional%20or%20Olympic%20level

2. Heat illness. NATA. (2019, July 12). Retrieved June 2, 2022, from https://www.nata.org/practice-patient-care/health-issues/heat-illness 

3. Kerr, Z. Y., Casa, D. J., Marshall, S. W., & Comstock, R. D. (2013). Epidemiology of exertional heat illness among U.S. high school athletes. American Journal of Preventive Medicine, 44(1), 8–14. https://doi.org/10.1016/j.amepre.2012.09.058 

4. Estimated probability of competing in college athletics. NCAA.org. (n.d.). Retrieved June 2, 2022, from https://www.ncaa.org/sports/2015/3/2/estimated-probability-of-competing-in-college-athletics.aspx#:~:text=Nearly%20eight%20million%20students%20currently,the%20professional%20or%20Olympic%20level. 

5. Casa, D. J., DeMartini, J. K., Bergeron, M. F., Csillan, D., Eichner, E. R., Lopez, R. M., Ferrara, M. S., Miller, K. C., O'Connor, F., Sawka, M. N., & Yeargin, S. W. (2015). National Athletic Trainers' Association position statement: Exertional Heat illnesses. Journal of Athletic Training. https://doi.org/10.4085/1062-6050-50-9-07