Jan 29, 2015
Safe Practices

As the fall preseason approaches, there is no better time to talk to your school’s coaches about exertional heat illness. This special section is written specifically for coaches and can serve as a handout to them.

By Jessica Dysart Miles, Dr. Earl Cooper, & Dr. Michael Ferrara

Jessica Dysart Miles, LAT, ATC, is a doctoral student at the University of Georgia and was previously an Athletic Trainer at the Children’s Hospital at Memorial University Medical Center and Homewood (Ala.) High School. She received an NATA Research & Education Foundation Award Scholarship in 2011, and can be reached at: [email protected].

Earl Cooper, EdD, ATC, CSCS, is the Associate Department Chair for Kinesiology and Clinical Coordinator for Athletic Training Education at UGA. He serves as the Co-Chair of the Southeast Athletic Trainers’ Association Educators Conference and received an NATA Distinguished Athletic Trainer Service Award in 2006. He can be reached at: [email protected].

Michael Ferrara, PhD, ATC, FNATA, is Associate Dean of Research and a Professor of Kinesiology at UGA. He is a member of the National Athletic Trainers’ Association (NATA) Research & Education Foundation Research Committee and is Past-President of the World Federation of Athletic Training and Therapy. Dr. Ferrara was inducted into the NATA Hall of Fame in 2009. He can be reached at: [email protected].

Some of the hottest and most humid weeks of the year are around the corner. Combining the weather with tough preseason practices and the protective equipment worn by some athletes can be a recipe for disaster. A year doesn’t go by that we don’t hear about athletes suffering from exertional heat illness (EHI)–some even die as a result of it.

The good news is that EHI is preventable and if it does occur, treatable. If you have a certified athletic trainer present at practices, your athletes are in safe hands. But even though your athletic trainer will keep an eye on the conditions and monitor your athletes, it is helpful for you to know what will happen should one of your athletes begin suffering from heat illness. And sometimes, athletic trainers aren’t present so it’s up to you to keep your athletes as safe as possible. To do that, you need to be aware of the various types of EHI, as well as their signs and symptoms.


Many people believe that EHI must happen in a specific sequence and that an athlete cannot have the most serious heat illness, heat stroke, without first experiencing cramps or heat exhaustion. This is generally false. While heat illnesses can occur on a continuum, they don’t always happen this way.

For example, an athlete can go immediately from functioning normally to having heat stroke. This is why it is important to know about the different types of EHI.

Exertional heat cramps: One of the most common and well-known heat illnesses, exertional heat cramps strike fairly suddenly and cause the affected muscles to become rigid. It is very painful for an athlete and usually leaves them unable to continue physical activity.

There are many schools of thought as to what causes heat cramps, but the most likely is an electrolyte imbalance in the affected muscles. In a nutshell, electrolytes (sodium and potassium) help the body hold on to more of the fluid that has been consumed, which is very important when hot, humid weather causes athletes to sweat out large amounts of fluids. Water, which doesn’t have electrolytes, is not always enough to rehydrate athletes who are sweating heavily. Sports drinks are very helpful in these circumstances because they are fortified with electrolytes.

When you think an athlete is suffering from exertional heat cramps, the first thing to do is help them stretch the affected muscles. It may be painful for the athlete at first, but it will help the cramp subside. The athlete should also replenish electrolytes lost due to sweating by rehydrating as soon as possible. A sports drink is most beneficial, but water is a good second choice. Finally, because a muscle cramp is a sort of spasm, ice massage may also help the athlete recover. Other products have been purported to ease muscle spasms, such as pickle juice and mustard, but there is no research to support these claims.

If the athlete plans on returning to action after the cramp subsides, it is very important to make sure the affected muscles are stretched out further and that the athlete warms up again before hitting the field. For athletes who suffer from exertional heat cramps on a fairly regular basis, as long as they don’t have a history of hypertension, adding salt (sodium) to their diet may help prevent cramps in the future.

It’s important to note that not all heat cramps are the same. Sickle cell crisis can present as heat cramps and sickling is often confused with heat cramping. If an athlete is a habitual cramper, the athletic trainer or the athlete’s doctor may suggest that they be tested for sickle cell trait. For those athletes who are known to have sickle cell trait, there are important distinctions between exertional cramps and heat cramps due to sickling. According to the NATA Concensus Statement on Sickle Cell Trait and the Athlete:

– Heat cramping often includes muscle twinges, but sickling does not. – Heat cramps are much more painful. – Athletes suffering from heat cramps often begin to hobble, complaining of “locked up” muscles, while players with sickling usually slump to the ground with weak muscles. – Athletes with heat cramps often writhe and yell out in pain and their muscles are visibly contracted and rock hard. Athletes with sickling tend to lie still, not saying anything, and their muscles appear and feel normal. – When sickling is caught early and treated right away, athletes usually recover faster than those with major heat cramping.

Heat syncope: The main symptoms of heat syncope are dizziness and sometimes fainting (syncope is another word for fainting). This condition occurs when there is pooling of the blood in the lower extremities (thighs, calves, etc.) as a result of overheating and subsequent low blood pressure. When blood pools in the lower body, it is not making the rounds in the body’s circulation system, reducing the amount of blood, and thus oxygen, to the brain.

The body’s initial response to the lack of oxygen to the brain is to “faint” so the body lies down and is in a better position for blood flow. The dizziness results from the initial lack of oxygen and fainting occurs when the athlete doesn’t stop, or at least slow, their activity. Other symptoms associated with heat syncope are dehydration, fatigue, tunnel vision, pale or sweaty skin, decreased pulse rate, and lightheadedness.

If one of your athletes begins feeling dizzy or shows any other symptoms of heat syncope, remove them from the hot environment, take off any protective equipment, and get them to rehydrate. Moving them to an air-conditioned building is best, but isn’t always an option, so the athlete should at least get to a shaded area to lie down and place a cool towel or sponge over their head and/or neck. Lying down and elevating the feet above the head encourages blood flow to return to the heart, allowing for an increased amount of oxygen to return to the brain. After symptoms have cleared, usually in about 10 minutes, the athlete can return to activity with caution.

Heat exhaustion: Heat exhaustion occurs when the body is unable to cool itself in a normal way through sweating. It usually results because of dehydration, but other factors–including illness, poor nutrition, and lack of acclimatization–can also increase the risk of heat exhaustion.

Common signs and symptoms include a slightly elevated core body temperature of 100 to 103 degrees Fahrenheit, dehydration, dizziness, lightheadedness, syncope, headache, nausea, pale skin, persistent muscle cramps, profuse sweating, chills, clammy skin, weakness, and hyperventilation. Any combination of these symptoms is a red flag that an athlete is in, or close to, danger.

If you suspect an athlete is suffering from heat exhaustion, he or she must be removed from the hot/humid environment as quickly as possible and efforts must be made to rehydrate them and immediately cool their body. An ice bath or tub is the best way to quickly lower body temperature, however, ice bags, cold towels, and/or sponges placed in the groin, armpit, and neck regions will also help if a bath or tub is not available.

If the athlete begins to feel better, he or she should not be sent back out to practice, but referred to their physician who may run further tests. Final clearance for return to activity after a heat exhaustion episode should always be given by a physician. If the athlete’s condition does not improve, you should assume they are suffering from heat stroke and emergency services should be contacted immediately.

Heat stroke: The most serious EHI is heat stroke. This is a medical emergency, and if not treated promptly and properly, can result in death. The key differences between heat exhaustion and heat stroke are core body temperature and nervous system disruption. When heat stroke occurs, the body’s ability to cool itself has completely shut down.

If an athlete’s temperature is higher than 104 degrees and they exhibit changes in behavior like drowsiness, irrational behavior, confusion, irritability, emotional instability, hysteria, apathy, aggressiveness, delirium, disorientation, or loss of consciousness, heat stroke should be assumed and emergency services should be contacted immediately. Other warning signs include seizures, dehydration, weakness, hyperventilation, vomiting, and diarrhea.

While waiting for emergency services to arrive, you must cool the athlete’s body immediately. The most efficient method is cold water immersion. If not available, a cold shower, cold towels, or cold sponges are the next best options. If the athlete is conscious and not vomiting, give them fluids to help rehydrate them. Heat stroke is the only injury where it is essential to treat first (cool the body) and transport second. As with heat exhaustion, return to activity should be granted only by a physician.


As sports medicine researchers learn more about the different types of heat illnesses and what causes them, we are also learning more about preventative methods. Though we know coaches cannot control the heat or humidity, you have quite a few options for handling it.

Acclimatization: Acclimatization is the natural process the body undergoes to get used to a stressful environment. Specifically, decreases in heart rate, core body temperature, and electrolyte losses through sweat and urine will ultimately allow an athlete to continue with physical activity in stressful environmental conditions. In the case of the summer months, this means heat and humidity.

What is an adequate amount of time for acclimatization to occur? This depends on a wide variety of factors, but research has found that, generally speaking, the greatest effects of acclimatization occur within the first 10 to 14 days of exposure to the heat. Smaller changes continue for up to a month.

For football players, the NCAA and National Athletic Trainers’ Association (NATA) suggest an acclimatization period at the beginning of the season. The NCAA and many state high school athletic associations have implemented rules that limit an athlete’s practice activity until they have had a chance to adapt to the conditions. The NATA recommends that this acclimatization period span five days and specifically dictates practice length, number of sessions per day and the type of equipment that can be worn. The key to acclimatization is allowing the body to gradually get used to the environment. This includes slowly increasing the intensity and length of workouts. For football players, this also means gradually increasing the amount of protective equipment worn.

For example, here in Georgia, new high school rules state that football players may not wear any protective equipment during the first five days of preseason practices, except for a helmet and mouthguard. Once players have completed five days of single-session practices that last no more than two hours each, two-a-days are permitted, but with the following stipulations:

– No single session may last longer than three hours – The total amount of time in the two practices shall not exceed five hours – There must be at least a three-hour break between sessions – There may not be consecutive days of two-a-day practices – All double-session days must be followed by a single-session day or a day off.

Fluid intake/replenishment: All types of EHI have a common thread of dehydration. It is imperative that athletes are well hydrated throughout the day before they begin a workout, and that they continue to hydrate throughout practice sessions and games so that they are replenishing fluids lost via sweat. Changes in the body’s response, and consequent performance decreases, can occur with as little as a one- to two-percent decrease in body weight fluid loss.

There are precise measuring tools for hydration like refractometers and urine strips, but the simplest way to determine hydration status is by color of urine. The clearer (pale yellow or translucent) it is, the more hydrated an athlete is. The darker yellow it is, the more dehydrated they are. You can find and print out color charts to post in the locker room restroom stalls so the athletes are aware of what color their urine should be. (See “Resources” for where to find a downloadable chart.)

The NATA Position Statement on Exertional Heat Illnesses recommends the following general guidelines to ensure proper hydration:

– 17 to 20 ounces of water or sports drink two to three hours prior to exercise – Seven to 10 ounces 10 to 20 minutes prior to exercise – Seven to 10 ounces every 10 to 20 minutes during exercise – Eight ounces after exercise.

As preseason practices begin around the country, it is important that you understand the role you play in keeping your athletes free from heat illness. EHI can be avoided if the strategies in this article are adhered to. And if an episode occurs, you now know what to do to prevent a case from getting worse.


There are two ways to measure environmental stress: The heat index (HI) and the wet bulb globe thermometer (WBGT). The general population is most familiar with the HI because it is often printed in the newspaper or reported during the evening newscast weather segment. However, the WBGT is a more accurate measuring tool when assessing whether practices need to be altered.

The HI combines the effect of two variables on the body: ambient air temperature and humidity. It was designed to reflect the average person, who the HI assumes is approximately 5-foot-7, weighs 147 pounds, wears long pants and a short-sleeve shirt, is in the shade, and is walking at a pace of three miles per hour. Clearly, this is not even close to the average high school football player during a preseason practice.

The WBGT comprises three factors: ambient air temperature, humidity, and radiant heat. The additional measurement of radiant heat in the WBGT means that the effects of surrounding factors like playing surface (grass vs. synthetic turf) are taken into account.

Agencies including the American College of Sports Medicine, the U.S. Department of Defense, and the National Athletic Trainers’ Association have all published position statements regarding athletic participation in extreme environmental conditions, and they all agree that the WBGT is the best way to dictate practice protocols based on environmental conditions. If your school’s heat policy doesn’t call for WBGT over the HI, you should encourage that this change be made.


Downloadable urine chart: http://www-nehc.med.navy.mil/downloads/healthyliv/nutrition/urinekleurenkaart.pdf

NATA Position Statement on Fluid Replacement for Athletes: http://www.nata.org/sites/default/files/FluidReplacementsForAthletes.pdf

NATA Consensus Statement on Sickle Cell Trait and the Athlete http://www.nata.org/sites/default/files/SickleCellTraitAndTheAthlete.pdf

For past Training & Conditioning articles on heat illness: Search “heat illness” on our Web site at: www.Training-Conditioning.com


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