All across the country, secondary school athletes are going through the annual ritual of preseason camp. As preseason practices quickly approach, so does the impending risk of an athlete succumbing to exertional heat illness. For this reason, all secondary school athletic programs throughout the country should be implementing an effective heat-acclimatization plan to help ward off this looming potential casualty.

Fortunately, awareness seems to be on the rise. In 2003, the National Collegiate Athletic Association (NCAA) established practice guidelines that touched on heat-related events among other injuries and conditions. Using the NCAA benchmarks as a general template, the National Athletic Trainers' Association (NATA) created a multi-organization task force to release comprehensive guidelines for heat acclimatization in secondary school athletes. The guidelines were published in the Journal of Athletic Training in 2009, marking the first time for secondary school-specific rules to be listed in a medical journal.

Heat illness is a potentially deadly circumstance across all sports. But with increased face time with athletes and attention to the initial 14-day acclimatization period, athletes can be protected from heat-related health events.

Cause for Concern

Sports participation is at an all-time high in the United States. Practice seasons and playoffs are longer, competition is more vigorous, and multi-sport participation among school-aged children is growing.

While higher sports participation is welcome news to health experts who espouse the benefits of physical activity during youth, it can raise concerns as well. For instance, the decade of the 2000s has seen the highest death rate from exertional heat stroke since the 1960s. An estimated 18 student-athlete fatalities occurred in a 10-week period between late July and early October 2008.

While we can't entirely explain the recent spike in fatalities, we know of multiple strategies that can lower the risk. One major step to enhance an athlete's exercise heat tolerance, physiologic function and exercise performance is by following a proper heat acclimatization program.

The acclimatization program should provide for gradual increases in frequency, duration and intensity of physical activity, in addition to the phasing in of protective equipment. Although football players may be at a higher risk for heat-related illnesses-due to their increased body weight and amount of protective equipment worn-the guidelines are not football-specific. Exertional heat illness is non-discriminatory. It can occur in males or females, football or field hockey, freshmen or varsity, outdoors or indoors. These guidelines can keep all athletes safe from serious harm, but they must be followed consistently.

Preseason Acclimitization

Historically, the preseason is the most critical period for heat-related illness, and thus the most critical to establish strict guidelines. Before participating in the preseason practice period, all student athletes should undergo a pre-participation medical examination by a physician or as required by state law. This will help identify any predisposing factors such as asthma or a cardiac condition.

Based on the best available evidence, the initial 14 consecutive practice days make up a heat acclimatization period, which begins on the first day of official practice prior to the season, regardless of any summer conditioning. Over these 14 days, athletes become more tolerant to the heat, allowing them to exercise safely and effectively in warm to hot environments. During this period, total practice time shouldn't exceed three hours. "Practice" refers to the time an athlete participates in a coach-supervised, school-approved sport or conditioning-related activity, including warm-up and cool-down exercises, and conditioning and weight-room activities.

Face time is important during practice, especially at the secondary school level. Student athletes need as much eye-to-eye contact and instruction as possible for sport skill and safety during competition. During this teaching opportunity (or walk-through) athletes should not wear protective equipment such as helmets, shoulder pads, catcher's gear or shin guards, or use sports-related equipment such as footballs, lacrosse sticks, blocking sleds, pitching machines, soccer balls or marker cones. Walk-throughs shouldn't exceed one hour per day. It's not part of the practice period, nor does it include conditioning or weight-room activities.

The recovery period is equally important, marking the time between the end of one practice or walk through, and the beginning of the next. This doesn't include any exercise or walk-through, though treatment of injuries is permissible. Following practice, athletes should rest and hydrate in a cool environment for three continuous hours. Dehydration can strike with as little as a 2 percent loss in body weight during practice, so replenishing lost fluids is vital to recovery.

Seven-Step Plan

The recommended acclimatization plan encompasses seven specific parameters during the initial 14-day period.

1. On days one through five, athletes may not participate in more than one practice per day, not to exceed three hours in length.

2. If practice is interrupted by inclement weather or heat restrictions, the practice may recommence once conditions are deemed safe. Total practice time should not exceed three hours per day.

3. A one-hour maximum walk-through is permitted during days one through five. However, three three-hour recovery periods should be inserted between the practice and the walk-through (or vice versa).

4. During days one through two of the heat-acclimatization period, in sports requiring helmets or shoulder pads, a helmet should be the only protective equipment permitted (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 6, all protective equipment may be worn and full contact may begin. For football, on days three through five, contact with blocking sleds and tackling dummies may be initiated. For full-contact sports, 100 percent live contact drills should begin no earlier than day six.

5. Beginning no earlier than day six and continuing through day 14 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 continuous hours of 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 should exceed three hours in duration and student athletes should not participate in more than five total hours of practice. Warm-up, stretching, cool-down, walk-through, conditioning, and weight-room activities are included as part of the practice time. The two practices should be separated by at least three continuous hours in a cool environment.

7. Due to the high risk of exertional heat illness during the preseason heat-acclimatization period, the task force guidelines strongly recommend that an athletic trainer be on site before, during and after all practices.

It's important to remember that this is not a 100-degree temperature issue. Every player needs to get acclimatized to their particular area or geographical region. Coaches should realize that these guidelines don't mark a radical shift in their practices. For instance, the guidelines don't eliminate two-a-day practices-they phase them in.

According to a 2009 NFHS survey, 42 states already implement some type of heat acclimatization guidelines. Awareness among state athletic associations, school districts, boards of education and coaches should begin implementing the task force guidelines in order to create a safe practice environment for their student athletes. Contrary to what many believe, there is a nationwide problem. Our casualty numbers tell us so.

This article was produced in cooperation with the National Athletic Trainers' Association (NATA), the professional membership association for certified athletic trainers and those who support the athletic training profession. For more information visit www.nata.org

David Csillan is an athletic trainer at Ewing High School in Ewing, NJ, and a member of the New Jersey State Interscholastic Athletic Association Sports Medicine Advisory Committee. Douglas Casa is director of athletic training education, associate professor of kinesiology, and research associate of the Human Performance Laboratory in the Neag School of Education at the University of Connecticut in Storrs.

Thermometers: Which is Best?

By Julie DeMartini, MA, ATC, PES

As one of the top three leading causes of sudden death in U.S. college and high school athletes, exertional heat stroke (EHS) has become a significant concern for athletes, coaches, and medical professionals alike. While hyperthermia is common in the athletic population, and exertional heat illness (EHI) is an inherent risk for any individual who performs intense exercise in the heat, severe hyperthermia can result in dangerous and potentially life threatening situations.

The recent increase in deaths attributed to EHS has stimulated a greater interest in its prevention, recognition, and treatment, including a 14-day heat acclimitazion program, recently endorsed by the National Athletic Trainers Association (NATA) as a preventative measure to decrease the risk of EHI in the athletic population.

In addition to preventative measures, it's crucial to implement an appropriate method of temperature assessment to properly recognize a case of EHI. If an invalid device is used (such as an oral thermometer, tympanic thermometer, axillary thermometer, skin temperature stickers and the like), EHS may go undiagnosed, as these devices often record much lower than the true core body temperature.

In current research and clinical settings alike, it's been accepted that the ingestible thermistor and rectal thermometer are the only valid methods to accurately and practically assess core body temperature. However, while these devices have been deemed appropriate, other non-validated means continue to be used by medical personnel. The misuse of these devices can prove detrimental, and sometimes fatal, when attempting to accurately diagnose EHS, as an incorrect temperature assessment could lead to mistreatment.

While rectal temperature is the primary method of acquiring an accurate temperature in an acute case of EHS, ingestible thermistors can also be used to track an individual's body temperature. The ingestible thermistor resembles a capsule, and is swallowed to allow passage into the stomach. The device transmits a signal that is obtained by a receiver that is held near the individual.

In addition to the accuracy of this method, other advantages include being minimally invasive and the ability to assess temperature immediately. Furthermore, and possibly most important in the athletic setting, these sensors can be used to track body temperature changes over a constant, extended period of time, as well and assess potential hyperthermia before a life-threatening situation arises.

This could be most beneficial during preseason practices when teams are often exercising for an extended period in the heat (such as football two-a-days). However, as it takes approximately four hours for the pill to pass into the gastrointestinal tract to obtain an accurate reading, these pills cannot be used for an immediate assessment of core body temperature once ingested.

With the recent high profile deaths from EHS of high school and collegiate athletes, appropriate management of these cases must become a priority for all personnel involved with these athletes. While the ingestible thermistor provides accuracy and is easy to use, this is one device that can assist in the recognition of EHI to keep athletes safe.

Julie DeMartini, MA, ATC, PES, is a doctoral student and laboratory instructor in the department of kinesiology at the University of Connecticut in Storrs.