Maximizing Player Performance

Heat-related illness prevention in football
by: AFM Editorial Staff
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Coaches don’t need as much reminding these days. The summer of 2001 brought heat-related football illnesses to the forefront.

The death of the Minnesota Vikings’ Korey Stringer in 2001 brought a rash of media attention to the issue of staying cool during football training camp. It was indicative of a larger issue – from 1960 to 1998, there have been 91 documented heatstroke deaths related to football.

When the story became national news, coaches took notice. Today, focus on heat-related illness in football is at its highest level ever.

“Kids and professionals have died from this – this is serious,” said Larry Kenney, Ph.D., professor of physiology and kinesiology at Penn State. “A smart coach will realize that it’s not just college and pro players who is at risk.”

Still, progress is being made to find the best ways to keep players cool. By avoiding heat-related illness, coaches, athletic trainers and strength coaches can not only keep the team healthy, but keep athletes performing at the highest level.

Why Do Players Get Hot?

One issue with the football season in general is that two-a-day practices tend to start when the environmental temperature is at its highest. In most towns across America in the beginning of August, heat and humidity can be sweltering. Even in a “dry heat,” the sun’s rays – or solar radiation – can cause a player to overheat.

To counteract this, coaches are encouraged to begin two-a-days early in the morning and late in the afternoon, when heat and humidity are at their lowest. Also, coaches are encouraged to check the day’s heat index and adjust practice if the reading is at a dangerous level.

“We know that coaches are going to want to practice – they’re competitive and want to win,” said Rob Skinner, director of sports nutrition at Georgia Tech and director of the Homer Rice Center for Sports Performance. “You just have to adjust. For example, you don’t do all the drills that day; cut back on some of the heavy running or build in more fluid breaks for water or a sports drink.”

An often-overlooked factor in a player’s body temperature is the uniform he has on. With advances in breathable materials and padding, players can keep cooler than ever. However, the easiest way to adjust the uniform to keep players cool is to allow them to wear “shells” when possible.

A study by Penn State compared a player’s core temperature when wearing a full uniform versus “shells” - helmet, undershirt, shoulder pads, jersey and shorts. Working with the assumption that overheating is caused by a lack of balance in the body’s ability to heat and cool itself, the study found that the “shells” allowed for a greater heat balance in severe environments.

The research suggests that coaches can help keep their players cooler by allowing them to wear “shells” instead of full pads during practice, especially the first few days of two-a-days.

Because most cases of heat illness occur during the first few days of practice – while players’ bodies acclimatize to the heat – experts recommend that coaches not use full pads in practice until at least the third day of two-a-days.

Who is Most Likely to Overheat?

On one side of the practice field is a large offensive lineman, laboring through the first week of two-a-day practices. On the other side of the practice field stands a small, lighting quick running back, hustling through practice and appearing to make it through drills with relative ease.

The offensive lineman is the most likely to overheat, correct?

Yes and no.

“Sure, maybe linemen and bigger guys are more likely to overheat,” Kenney said. “But regardless of size, early in camp it can be difficult for ALL players to get acclimated to the heat.”

Larger players do have a few factors working against them when it comes to their ability to stay cool. They generally exhibit a lower aerobic fitness level and their bodies are typically slower to acclimate to the heat once practice begins. The larger players also have smaller skin surface-to-mass ratios, meaning that they might not cool off through sweating as efficiently as a smaller player.

All other things being equal, heavier players do run a greater risk of overheating during two-a-day practices than their leaner counterparts. At the same time, it’s important that all players have prepared themselves properly to compete in the heat.

“If we could figure out beforehand who was more likely to overheat, it would be great,” said Skinner. “But I’ve had problems with skinny and not-so-skinny players alike. It’s not exclusive to certain body types.”

“What it comes down to is being ready for practice.”

To be ready, experts advise that players try to put their bodies in the best condition possible for the start of practice and begin the acclimatization process in advance.

How Do Players Avoid Overheating?

The key to helping keep players from overheating is to ensure that their bodies adapt to practicing in the heat. Called heat acclimatization, a player’s ability to adjust to drills, the weather, helmets and padding is essential to keeping cool.

Not only does working out in advance of the season help with heat acclimatization, it helps improve aerobic fitness, too. Being aerobically fit and in good “football” shape can help a player get through two-a-days and reduce the risk of putting his body in danger of overheating.

“Sure, maybe linemen and bigger guys are more likely to overheat. But regardless of size, early in camp it can be difficult for ALL players to get acclimated to the heat.” - Larry Kenney, Ph.D.

“Athletes should begin working out to get ready for two-a-days about a month before they start,” said Douglas Casa, Ph.D., associate professor of kinesiology and director of athletic training education at the University of Connecticut. “Athletes also need to teach themselves how to stay hydrated. When they work out, they need to drink a large amount to get their bodies used to taking in fluids.”

Once the season starts, experts say coaches need to focus more on keeping their players hydrated before and after practice, not just during practice.

“Without question a sports drink is better than water,” Casa said. “The flavor and sodium encourage you to drink more. You also replace some of the sodium you’ve lost during workouts and you get a burst of energy from the carbohydrates in the drink.”

Coaches should weigh their players before and after practice to track fluid loss and take players out when they do not gain enough weight back between practices. The goal is to make sure athletes replace the fluids they’ve lost without drinking too much. A weight gain after exercise indicates that an athlete has been overhydrating, which can lead to a serious and sometimes deadly condition called hyponatremia. Hyponatremia occurs when too much fluid is taken in and the blood sodium concentration becomes diluted, causing the brain to swell.

Skinner – like most college nutritionists – makes sure his players eat at least two meals a day during two-a-day practices. “People don’t realize that food can contribute to hydration,” he said. He also ensures that they drink at least three 16-ounce glasses of fluid during the meal, and hands them a bottle of sports drink or water before they hit the showers after practice and at least a half-hour before practice begins.

He also tells players not to go home and go straight to sleep - after all, they can’t drink fluids if they’re asleep – and to avoid drugs, tobacco and alcohol, which affect the body’s hydration and performance.

Finally, Skinner makes sure his Georgia Tech players carry a 32-ounce bottle filled with water or a sports drink such as Gatorade home with them every day.

“That way, when they go back to their dorm, we know they’ll have something to drink,” he said. “There’s no excuse not to stay hydrated.”

Recognizing Heat Illness Dehydration leads to increased risk of heat illness. In order to prevent heat illness, you must first recognize the warning signs of dehydration, which include: • Headache • Irritability • Dizziness • Fatigue • Weakness • Muscle Cramps Treatment of dehydration and heat illness should take place immediately. If symptoms persist or include disorientation, heat flush, abnormal chills, vomiting, nausea and/or altered consciousness, there is a real risk of heat stroke. This is a serious condition that requires immediate medical attention. Depending on the severity of the situation, seek assistance from a certified athletic trainer or dial 911 for emergency medical services. It is important that both coach and player alike understand the dangers of suffering in silence. If a player is experiencing warning signs of dehydration, he has to KNOW that it is okay – and in fact encouraged – to speak up so he can get the rest, fluid and medical attention he needs. These symptoms can also be associated with hyponatremia, which also requires immediate medical attention.

Know Your Heat Index Perhaps the most important cause of heat-related illnesses is the environment, or weather during practice. While heat – and the radiation of the sun, both out in the open and in the shade – contributes to the amount of heat the body absorbs, humidity is the most important factor of weather. The reasoning goes like this – the body is cooled when an athlete sweats, but not by the sweat itself. Instead, the process of air evaporating the sweat is what cools the skin. That said, the more humid the temperature, the longer it takes for the body’s sweat to evaporate and conduct the cooling element to the skin. “You want the sweat to dissipate,” said Rob Skinner, the director of sports nutrition at Georgia Tech. “When it’s humid, sweat stays on the body longer, and that’s not a good thing. It’s not helping to cool the body.” Because of the importance of humidity in terms of the body’s temperature, coaches are encouraged to consult the Heat Index, a chart that measures the “apparent temperature,” a combination of the actual temperature and the percentage of humidity. When the “apparent temperature” is between 90 and 105 degrees, heat cramps or heat exhaustion is possible. From 105 to 130, they are likely along with the possibility of heatstroke. From 130 and up, heatstroke is likely. A copy of the Heat Index can be found on the Gatorade Sports Science Institute web site, www.gssiweb.com. Larry Kenney, Ph.D., professor of physiology and kinesiology at Penn State, said that the combination of heat and humidity is one of the most important factors of a player’s chances of a heat-related illness. Kenney said that it’s common sense for coaches to track the Heat Index. On especially dangerous days, he said, coaches should take common sense steps to keep their players cool, whether it be scaling back drills, removing pads or offering more fluid breaks. “We all know coaches are going to practice even when it’s really hot and humid,” Skinner said. “But they should adjust to the temperature, whether it’s by not running all the drills or giving the kids longer breaks. There should always be a sports drink or water nearby.” Skinner said the actual temperature shouldn’t be ignored, either. The sun’s rays produce solar radiation both in the heat and in the shade. Solar radiation itself, even without much humidity, is still enough to overheat a player. To combat solar radiation and humidity, Skinner recommends a sports drink such as Gatorade. “Fluid is what’s going to help a player keep cool the most, regardless of whether it’s humid or not,” he said. “It’s like a car’s radiator.” A radiator that shouldn’t overheat if the proper measures are taken.

Combating Heat Illness Here are six factors all coaches should be cognizant of in preparing their athletes to compete in the heat. 1. Acclimatization: One reason that two-a-day practices can be dangerous is because some athletes are not used to the outdoor conditions when practice starts. An athlete should train outdoors for at least one month before two-a-days to get his body adjusted to the climate of practice. 2. Hydration: Athletes should drink a sports drink such as Gatorade or water as often as needed during practice to replace sweat losses as indicated by body weight. Not only will the break help cool the body, it will help to increase performance through the life of the practice. 3. Fitness Level: Athletes who are not in the proper shape will usually have more difficulty staying cool and performing at a higher level than athletes who are in shape. 4. Intensity of Exercise: A more stressful workout will always cause a player to get hotter, faster, regardless of the temperature. 5. Environment: The more hot and humid it is, the more difficult it is for an athlete to keep his or her core temperature cool. Try to practice early or late in the day, when the temperature is cooler and less humid. Always consult the Heat Index for the heat stress risk and adjust practice plans accordingly. 6. Equipment and Clothing: Breathable fabrics help an athlete stay cool by allowing air to flow to the skin and cool it. Be cautious of fabrics that might claim to wick water off the skin’s surface, as the act of sweat evaporating off the skin itself is what helps to cool the body.

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