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From The National Athletic Trainers' Association

Pre-Season Heat-Acclimatization Guidelines

High School-Specific Guidelines For Reducing Heat Illness Risk

Player and tackling dummy

In 2009, the National Athletic Trainers' Association (NATA) issued  high school-specific pre-season heat-acclimatization guidelines as part of its ongoing effort to reduce the number of heat-related athletic injuries in secondary schools.


The consensus statement lists seven key recommendations for a 14-day heat-acclimatization period prior to full-scale athletic participation by secondary school students:

  1. During the first five days of the heat-acclimatization process, no more than one practice per day.
  2. If a practice is interrupted by inclement weather or heat restrictions, the practice should recommence once conditions are deemed safe, but total practice time should not exceed three hours per day.
  3. A one-hour maximum walk-through is permitted during the first five days of the heat-acclimatization period, with a three-hour recovery period between the practice and walk-through (or vice versa).
  4. Helmets only during the first two days (no shoulder pads). Goalies, as in the case of field hockey and related sports, should not wear full protective gear or perform activities that would require protective equipment. During days three through five, only helmets and shoulder pads should be worn. Beginning on day six, all protective equipment may be worn and full contact drills may begin.
  5. Beginning no earlier than the sixth day and continuing through the 14th day, double-practice days must be followed by a single-practice day. On single-practice days, one walk-through is permitted, but it must be separated from the practice by at least three hours of continuous rest. When a double-practice day is followed by a rest day, another double-practice day is permitted after the rest day.
  6. On a double-practice day, neither practice's duration should exceed three hours total, and total practice time should be limited to a maximum of five total hours. Warm-up, stretching, cool-down, walkthrough, conditioning and weight-room activities are included as part of the practice time. The two practices should be separated by a break of at least three continuous hours in a cool environment.
  7. Because the risk of exertional heat illnesses during the pre-season heat-acclimatization period is high, the consensus statement strongly recommends that an athletic trainer be on site before, during, and after all practices.

Heat stroke deaths on rise

Deaths of high school athletes from exertional heat stroke have been on the rise in recent years (six during the summer of 2011 (1)). The NATA's guidelines provide critical education for student athletes, parents, coaches, athletic trainers, medical professionals and school staff on ways to reduce the risk of heat illness.

Athletic trainer Douglas J. Casa, PhD, ATC, FACSM, FNATA, co-chair of the task force and director of athletic training education at the University of Connecticut, revealed that "when an athlete undergoes a proper heat-acclimatization program, the body's response to exercise and heat is improved, while athletes not following a proper program face measurable risks for heat illness. A proper plan in secondary school athletic programs is essential to minimize these risks."

"Exertional heat stroke is the leading cause of preventable non-traumatic exertional sudden death for young athletes in the U.S., and studies strongly suggest that heat acclimatization appears to be one of the best strategies for reducing the risk of heat illness," says Francis G. O'Connor, MD, MPH, past president of the American Medical Society for Sports Medicine, associate professor at the Uniformed Services University and medical director for the Consortium on Health and Military Performance.

14-day heat acclimatization period

The heat-acclimatization period is defined as the initial 14 consecutive days of preseason practice for all student athletes. The goal of the acclimatization period is to radually increase exercise heat tolerance and enhance the ability to exercise safely and effectively in warm and hot conditions. This period should begin on the first day of practice or conditioning, prior to the start of the regular season. Any practices or conditioning conducted before this time should not be considered a part of the heat-acclimatization period.

Regardless of the conditioning program and conditioning status leading up to the first formal practice, all student athletes (including those who arrive at preseason practice after the first day of practice) should follow the 14-day heat-acclimatization plan.

David Csillan, MS, LAT, ATC, co-chair of the NATA task force and an athletic trainer at Ewing High School in Ewing, N.J., knows first-hand the dangers of heat illness in secondary students. According to Csillan, "these recommendations are only minimum standards, based on the best heat-acclimatization evidence available. Following these guidelines provides all secondary school athletes an opportunity to train safely and effectively during the preseason practice period." He also underscored the importance of a pre-participation physical examination administered by a physician for all student athletes.

George "Iceman" Gervin, a retired San Antonio Spurs player, NBA Hall of Fame recipient and champion of youth education and activities, supported the recommendations and important sports safety education. Gervin has founded a charter school and youth center, among other programs in the San Antonio community. "As someone who is committed to helping shape the future of our youth today - on and off the field and court - I applaud NATA and the other participating organizations on this important information. Here in San Antonio, we are making great strides to address youth wellness."

Other speakers on heat acclimatizaton at the NATA's 2009 annual meeting included Paul Saenz, DO, San Antonio Spurs team physician, who addressed the importance of these recommendations for all ages and levels of sport, from amateur to elite. "An integral part of these recommendations is to ensure all athletes are also well hydrated and that appropriate ventilation for indoor workout facilities and gyms are made available," he said.

Lynn Hickey, director of athletics at the University of Texas San Antonio, applauded the guidelines. She reinforced the importance of sports safety in secondary school sports and how vital this information is in college as well. "It is never too early to begin putting these guidelines into effect to ensure good health and safe sports participation."

In addition to NATA, the task force that developed the consensus statement comprises seven other groups, including American College of Sports Medicine, Gatorade Sports Science Institute, National Strength and Conditioning Association, United States Army Research Institute of Environmental Medicine, American Orthopaedic Society for Sports Medicine, American Medical Society for Sports Medicine and American Academy of Pediatrics.

Released at the NATA's 60th annual meeting in San Antonio in 2009, the statement also appears in the June 2009 issue of the NATA's Journal of Athletic Training.

As of May 2, 2013 the seven key recommendations of the statement have been adopted by state high school athletic associations in nine states (Connecticut, New Jersey, Texas, North Carolina, Georgia, Iowa, Arizona, Florida, and Arkansas) and are under active consideration in 14 others.

Source: National Athletic Trainers' AssociationKorey Stringer Institute.

Updated May 2, 2013



This is a "technology"

This is a "technology" issue. It's not any warmer now than 50 years ago, we've just become such an "air-conditioned" indoor society that kids aren't adjusted to the heat.

What to do? Get your kids outside during the day, don't let them sit in the house all day in air conditioning and by the pool. You aren't helping them by allowing them to stay indoors when it's 85 degrees or warmer. Our bodies will acclimate to the conditions we are most used to.

Football players, start running outdoors in July, don't wait until two-a-days begins to start getting in shape for the season.

heat acclimatization

While what John Dee says is true, I believe these recommendations are important. Sometimes teenagers will not heed the advice of parents, etc (no, really?). As the adults, then, it becomes our responsibility to try to do everything possible to keep our young people safe. These recommendations will potentially do just that - keep the young athletes safe.
Will they work? If coaches will adopt them, they will. The college level already uses them.

I am curious, however, why the National Federation of High Schools (the rule-making body for high school sports) spoke out AGAINST these recommendations. Sure, the number of heat deaths is low, but they are 100% preventable. Even one preventable death is too many.

Rick, while your philosophy

Rick, while your philosophy is good (one death is too many) it's an unrealistic goal. With that thinking, should we outlaw cars becuase just today, hundreds of people across the country will die in an automoble accident? Absolutely not.
Our responsibility as parents is to make sure our kids are ready to be out in warm weather before practice begins. Don't let your child sit inside the house 14 hours a day in air conditioning.

Ahh yes, the proverbial

Ahh yes, the proverbial "car" argument. Its called acceptable risk - and the threshold for automobiles has been set higher by our society than for high school football players. BTW, we have made (and will continue to make) improvements to cars which improve the death rate -seat belts, airbags, speed limits, alcohol limits, etc.

Will we ever prevent all deaths in high school sports? Probably not, but does that mean we shouldn't try? The fact that the risk is one in a million (or hundred thousand or whatever) matters little unless the "1" is your child (or is on MY field).

And, yes, JohnDee, I absolutely agree that the children should be out acclimatizing themselves in the warm weather. However, as the adults responsible for them when they go off to school/athletic practice, we have a duty to do everything possible to protect them from harm.

Rick, again I'm with you to

Rick, again I'm with you to a certain degree. But this is a slippery slope argument that just continues to roll. Like automobiles, there are already guidelines in place for high school football. Most states mandate "acclimation days" where they have to practice 2-3 days before they put the pads on. Fact is, most programs have extensive summer programs so the kids (those who choose to participate) are well conditioned when practices start.

I think there is a degree of "acceptable risk" in any athletics.