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Temperature Rising! Pre-Season Practices: Proper Hydration

by: Dan Weil
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Pre-season practice means hot weather, which brings with it the risk of dehydration and heat illness. While many people function quite normally with mild dehydration in everyday life, fluid deficits and heat illness are no laughing matters in football. The National Center for Catastrophic Sports Injuries stated that 19 high school football players died of heat stroke on the playing field between 1995 and 2005.

    We spoke to two experts about how to prevent serious dehydration and heat illness: Larry Kenney, Ph.D., professor of physiology and kinesiology at Penn State University, and Michael Bergeron, Ph.D., a professor at the Medical College of Georgia in Augusta. The pair discussed a handful of key themes for safety.

* First, players should acclimate themselves gradually to the heat of late summer.

    “Heat acclimation is the most important safeguard against heat illness in pre-season football,” Kenney said. “Almost every football-related heat death occurs on the first or second day of pre-season practice. That’s because of the number of players at every level who are showing up at practice without adequate exercise in a hot environment to let their body adapt.”

    Kenney recommends that players get used to exercising in the heat at least two weeks before practice begins. They should gradually build up their aerobic activity outdoors, without gimmicks like rubber suits, he said. “The first day you may run 15 minutes and then the next day 20 minutes.”

    To make sure that players are safe during the first week of practice, coaches at all levels should implement the acclimatization plan required by the NCAA, Kenney said. The NCAA doesn’t permit more than one practice per day for the first five days, and that one practice can’t last more than three hours.

     In addition, the only equipment that can be worn during the first two days is a helmet. Players can wear only helmets and shoulder pads – shells – for the third and fourth day. Starting on the fifth day, players can practice in full pads. The pads, particularly plastic ones, trap heat, making it hard for players to cool down.

      After the first five days, the NCAA allows teams to conduct two or three practices a day, but only every other day, and not for more than five hours. In addition, on days with more than one practice, players must be given at least three straight hours of rest between the end of the first practice and the start of the last one.

      Moderating the players’ workloads at the beginning of pre-season practice and giving them ample opportunity to cool down go a long way toward preventing heat illness. “The reason football players can get into trouble is because they aren’t acclimated to the environment, the uniform, the intensity, the duration, or all of the above,” Bergeron said. While coaches can’t manage the air temperature and humidity, they can control the acclimation process once the players report for practice, Bergeron pointed out.

      Much of the issue boils down to common sense. On days with the highest heat and humidity, “You don’t say, ‘We’ll make players wear full uniforms and run sprints,’” Kenney said. “I think coaches are by and large aware of that these days.”

* Second, proper hydration is crucial.  

     The issue is simple. As Bergeron put it, “Drinking is the best way to avoid dehydration.” But it takes some effort to make sure that players are really drinking enough. “From all my experience with various team sports, players tend to be slightly dehydrated all the time, and football players aren’t too much different,” Bergeron said.

     At two-a-day practices and even single-practice days, “players consume quite a bit less fluid on the field than what they lose, and they don’t make up for it at night,” he said. “So they come back the next day just as dehydrated or worse. In a study of high school players, we found them showing up pretty dehydrated after a few days of practice.”

     Mild dehydration doesn’t necessarily cause any problems in performing life’s routine tasks. But in sports, “research shows that even small levels of dehydration, if conditions are hot enough, will translate into weaker performance,” Bergeron said. That can mean a decrease in muscle control and the ability to make decisions. Dehydration can also sap desire, he pointed out.

    Kenney said a rule of thumb is that you don’t want players to lose more than 2 percent of their body weight during practice. “We have evidence from basketball and soccer that 2 percent impairs performance. The same is probably true in football,” he said. But football is harder to measure, because there’s not a common task like shooting the ball in basketball.

    Coaches, of course, should make sure their players drink up before, during and after practice. “There should be frequent rest breaks during practice sessions, particularly early on, where players can consume fluids,” Kenney said.

    Most experts agree that sports drinks like Gatorade can provide specific advantages over water because they replenish sodium and provide carbohydrates. Sodium helps prevent cramps and carbohydrates provide energy. In addition to helping prevent cramping in some players, “the sodium in sports drinks encourages players to continue drinking, while water can quickly quench your thirst before you regain all the fluid that you have lost,” Kenney said. “And for prolonged and intense practices, carbohydrates add fuel to the exercise.”

     But even for the most conscientious coaches, it’s hard to keep their players adequately hydrated at practice alone. The size of players and the burdens of their uniforms mean they’re losing a lot of fluid during practice. “You have players capable of losing two or three liters an hour,” Bergeron said. “You can’t expect them to match that with fluid intake.”

     So coaches should make sure their players drink adequately after practice too. “Football players need to pay attention to fluid recovery after sessions,” Bergeron said. “That’s the part that seems to be mismanaged the most.”

* Third, replace sweat losses.

     Experts recommend that teams weigh their players before and after practice to see how much fluid they are losing. Before the next practice, players should drink 1.3-1.5 times their fluid deficit, Bergeron said. That way they will be adequately hydrated after accounting for the fluid they will lose through urine during that period.

     Recent news coverage has raised awareness about over-hydration which can lead to hyponatremia. That condition develops when so much fluid is consumed that it dilutes the blood’s sodium concentration and can lead to brain swelling and death.

     But Kenney said hyponatremia isn’t much of a worry in football. “I don’t know of a single instance where that has happened in football. It’s tremendously over-hyped. It almost always happens in marathons and triathlons – things that last for hours and hours” and in which participants are constantly drinking, Kenney said. “Football players shouldn’t over-drink, but that’s almost impossible in practice. You’d have to be standing there guzzling water instead of going through drills.”

     Eating is important as well. “A lot of foods have high water content, so sometimes players don’t really replace all their fluids until they eat their next meal,” Kenney said.

     Food is also helpful in replenishing sodium. “That’s why we tell football players to liberally salt their food during periods of intense training,” Kenney said.

* Four, players should be watched carefully to make sure the heat isn’t doing them in.

     Athletic trainers and coaches should keep an eye on players to make sure they aren’t suffering from heat illness, while players should look out for each other too, Kenney said. Coaches can use a buddy system for players to keep track of each other. “The most severe form of heat illness is heat stroke,” Kenney said. “In almost every case, heat stroke is defined by mental impairment. Sometimes players get real dizzy and kind of stagger around, and sometimes they get a little incoherent.”

    If players start to look strange and can’t answer basic questions, they are likely suffering from heat stroke. “Some kind of goofy interlude” is a tip-off, Kenney said.
    Teams should have rapid forms of cooling available very close to the practice field, such as ice-cold water in which players can be immersed by an athletic trainer, he said. The best solution is to purchase a large, durable tub and fill it with ice water. At the very least, coaches can purchase a children’s sized wading pool for the same purpose. “It’s probably the safest $15 they’ll ever spend,” Kenney said. Whichever option a coach chooses, he or she should be cognizant of it’s ability to hold and safely contain their largest players. If the training room is near the practice field, a whirlpool tub can be used as well.

Extra Points - Does Size Matter?
 
    In addition to the four key safety themes laid out above, there is the issue of body size. A lack of proper preparation for summer heat probably explains why so many of the players who succumb to heat illness are big linemen, Kenney said. “They aren’t running five miles outside in July. They’re in air-conditioned rooms lifting weights.”

    Bergeron noted that heavier players are often out of shape. “If you’re large because you’re carrying a lot of fat, you may be out of shape. A lack of aerobic fitness may relate to a lack of ability to tolerate heat,” he said.

    Big players who are out of shape and not adjusted to the heat are particularly at risk when they’re pushed hard by their coaches or when they’re simply trying to avoid falling behind the other players at their positions, Bergeron said. “When a big guy tries to keep up at longer durations, then he can be at greater risk.”

     To be sure, it’s not just the big guys who are vulnerable to the heat. “Body temperature is not always related to size,” Bergeron said. “It’s not always the big guys who will heat up the most or the fastest.”

     For example, wide receivers can be slender but with a high percentage of muscle. “Because they tend to run a lot, they generate a lot of heat. Their body temperature can go up as fast or faster than a big guy,” Bergeron pointed out. Small players can be genetically inclined to heavy sweating too.

Supplements

     Questions also have arisen about taking supplements like creatine in the heat. “Creatine is a tricky issue,” Kenney said. “There were early anecdotes that creatine caused cramps. But it turns out to be a hydration issue. If you take it with enough water and Gatorade, there seems to be no effect of creatine on cramping. But you probably do want to take in more liquid if you take creatine.”





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