Reprinted from NFHS "High School Today"

 

Outside temperatures are on the rise and will be in full force just in time for athletes to participate in their summer and preseason practices. For this reason, it’s important for athletic trainers, coaches and school administrators to get a tune-up on potentially what lies ahead. With a little advance planning, the risk of your athletes experiencing a catastrophic event due to exertion heat illness will be significantly decreased.

There are various degrees of exertional heat illness with exertional heat stroke (EHS) being the most serious. Many athletic injuries are a result of bad luck or overtraining; however, EHS is 100 percent preventable if the nationally recommended heat acclimatization guidelines are followed and schools are prepared to initiate appropriate care if an emergency occurs.

The EHS death of Minnesota Vikings’ offensive tackle Korey Stringer during football camp in August 2001 elevated the discussion and action with regard to physical exertion in the heat.

The NFHS Sports Medicine Advisory Committee wrote a position statement and created an online course entitled A Guide to Heat Acclimatization and Heat Illness Prevention. The National Athletic Trainers’ Association (NATA) developed several position statements and published Preseason Heat Acclimatization Guidelines for Secondary School Athletics. The Korey Stringer Institute (KSI) was established to provide research, education, advocacy and consultation to maximize performance, optimize safety and prevent sudden death in athletes. The University of Georgia’s Climatology Research Laboratory released heat safety thresholds for specific regions throughout the country. These thresholds are currently being applied in the Georgia High School Association’s heat illness policy.

Now that we have the evidence-based data, we may ask ourselves “Why and how do we apply it”? In order to acquire a better understanding of EHS and its management, we must first debunk a few common myths.

Myth Busters 101
Myth #1: EHS can only occur when ambient temperatures reach 100 degrees F.

Truth: Evidence suggests that the wet bulb globe temperature (WBGT) should be the measurement of choice to determine safe environmental conditions for physical activity. The WBGT provides a reading of ambient temperature, relative humidity, wind speed and radiant heat (from the sun). Why is wind speed important? It allows for better evaporation of sweat leading to more effective cooling. Environmental conditions are constantly changing over the course of practice. As opposed to listening to the weather report prior to practice, the athletic trainer should monitor environmental conditions on site in real time. Utilizing a WBGT device and establishing activity modification guidelines such as work-rest ratios, hydration breaks, equipment worn and length of practice significantly decreases the risk of EHS.

Many coaches still refer to their area’s heat index when determining how practices will be conducted. Heat index refers to the ambient temperature and relative humidity measured in the shade and was originally used to determine if outdoor conditions were safe for the young and elderly. Since athletes are exercising in the direct sun, heat index readings are deemed inappropriate.

Although dangerous conditions most commonly occur during the hot summer months, EHS can happen at any time and in the absence of high environmental temperatures. EHS is not a 100 degrees’ issue. Geographical location plays an important role.

Generally speaking, athletes residing in the Northeast part of the country are accustomed to cooler temperatures compared to those in the Southeast or Midwest. As a result, participating in an environment of 85 degrees with high humidity for those living in the Northeast presents equal risk of EHS to those living in the Southeast and Midwest participating in temperatures reaching 100 degrees with high humidity. It is also important to understand that direct sun is not the sole contributor of heat deaths. Exercise intensity and environmental conditions are the primary factors associated with EHS.

Myth #2: An athlete must be severely dehydrated for EHS to occur.

Truth: While dehydration may predispose an athlete to, or exacerbate, EHS, dehydration does not always have to be present for EHS to occur. EHS can result in as little as 20 minutes after the beginning of exercise before severe fluid loss is prominent. The days of over-hydrating are gone as we’ve found this may put the athlete at risk for hyponatremia – another potentially catastrophic event.

During activity, athletes should be instructed to allow thirst to be their guide. Athletes should weigh themselves prior to, and immediately after, every practice. The weight should be recorded on a chart and strictly monitored by the athletic trainer or coach. A weight loss of two percent or more for any athlete should be made up prior to that athlete participating in the next practice. Otherwise, the athlete will be competing at a deficit and increasing their risk.

Myth #3: An athlete stops sweating during EHS.

Truth: We’ve been taught that heat stroke yields hot, dry skin on the victim. However, since EHS occurs during intense exercise in the heat, the athlete is almost always profusely sweating upon collapse. This is perhaps the most widely misunderstood sign of EHS and may lead to mistreatment and death. It’s important to review the current literature published by the NFHS, NATA and KSI in order to be updated on EHS signs, symptoms and management.

Houston, We Have a Problem
If EHS is suspected, it’s advised for the athletic trainer or coach to: remove the athlete’s equipment and excess clothing, contact EMS, determine vital signs and initiate rapid cooling by immersing the athlete
chest high in a tub of cold (39 – 59 degrees F) water. Core body temperature may elevate as high as 106 degrees F so it’s important to lower that as fast as possible. The typical rate of cooling in an immersion
tub is about ONE degree F every three minutes. On the average, it may take 15 minutes to cool the body five degrees. If an athlete is not cooled prior to transportation, the risk of developing complications or losing the athlete to EHS increases. Even though the EMS vehicle may be air conditioned, it’s not sufficient enough to lower the athlete’s core temperature during transport.

The Reality
Twenty athletes died as a result of EHS from 2010 to 2015. This five-year block was greater than any five-year block in the past 40 years. It’s two times the five-year block average for EHS deaths since 1975. The five-year block average over 35 years is 10.5 deaths. We must ask ourselves, “Things are getting worse, but why”?

The warmer climate, coupled with the fact that today’s youth spend more time than ever before in air conditioned facilities, sets them up as potential victims. Coaches need to remember that young athletes comprise this population and not everyone will be reporting to preseason camp acclimatized and in shape. The research and education is available but the application continues to lack. Unless we understand the nature of EHS and utilize best practices in emergency management, these statistics will continue to climb.

Exertional heat stroke is not exclusive to football. It is non-discriminatory. EHS can occur regardless of male/female, football/field hockey, varsity/freshman or outdoors/indoors. As athletic trainers, coaches and administrators, we owe it to our athletes to provide them with the safest environment to compete. And, we must start now.

Additional Resources
National Federation of State High School Associations (Sports Medicine Advisory Committee) – www.nfhs.org.
National Athletic Trainers’ Association – http://www.nata.org/practice-patient-care/health-issues/heat-illness.
Korey Stringer Institute - http://ksi.uconn.edu.
Grundstein A, et al. Regional Heat Safety Thresholds for Athletics in the Contiguous United States. Applied Geography. 2015:56:55-60

 

 

www.SportsSafety.org

Raise the Standard

Preventing Heat Exhaustion and Dehydration

---

Author: Amadeus Mason, M.D.

Heat-related illness and dehydration syndromes have always been concerns for coaches, athletes and their parents. The events of the 2001 NFL pre-season have served to heighten our concerns. Each year heat-related illness and dehydration syndromes affect thousands of athletes at all levels and continues to be among the leading causes of preventable sports injury and death.

What are we talking about?

Heat-related illness and dehydration syndromes include heat rash, heat cramps, heat exhaustion and heat stroke. These should not be seen as individual entities but as part of a continuum. The earlier the intervention, the better the odds of averting a disastrous chain reaction.

How does this work?

The skin is the key to the body's ability to regulate its temperature (thermoregulation). Once the brain senses that there is an increase in temperature, it initiates thermoregulatory mechanisms. The skin is the main cooling organ. It maximizes heat loss by using radiation, convection, conduction and evaporation. Radiation – heat is directly lost to the atmosphere. Convection – heat loss is facilitated by moving air or water vapor. Conduction – heat loss by direct contact with a cooler body. Evaporation – heat is lost by turning liquid (sweat) into vapor (the skin's major heat loss mechanism).

It's not so much the heat, it's the humidity. If the skin is so effective at cooling, why do athletes get into trouble? First, for any of the skin's cooling mechanisms to work, there needs to be adequate skin exposure. The problem is the much-needed sports safety equipment does not facilitate optimal skin exposure. Secondly, the environment needs to be conducive for heat transfer from the body. The combination of high temperatures and humidity severely impair the cooling mechanisms, especially evaporation. It is often the environment that athletes are training and competing in. For morphologic and physiologic reasons children do not adapt as effectively when exposed to heat stress, making young athletes more susceptible to heat- related illness and dehydration syndromes.

What can you do?

Stay cool:

• Work out in early morning or late evening. Avoid the hottest times of the day.
• Reduce the intensity and duration of your workout.
• Take the time to get into shape before arriving at training camp. Know the climate you are going to and try to get acclimated before getting there.
• Take frequent rests and remove your headgear. The head has an ideal body-mass to surface-area-ratio to maximize heat loss.

Stay hydrated:

• Drink often and drink regularly. Do not rely on thirst, by the time you are feeling thirsty, there is already a significant fluid deficit.
• Drink more than just water. When you exert yourself, you lose electrolytes as well as fluid. Replacing the fluid alone (with just water) can lead to electrolyte imbalances. These imbalances can be life-threatening.
• Monitor your urine, it should be the consistency of lemonade, not apple juice.

Stay healthy:

• Eat and sleep well. Maintain a well-balanced diet. Replenish salt and rehydrate. Avoid alcohol, soda, caffeine and other stimulants.
• Gain or lose weight slowly, allowing your body time to acclimate to the change.
• Sharp drops in weight after exertion can be an indicator of excessive fluid loss.
• Know the warning signs of heat related illness and dehydration syndromes.

What to look for?

• Confusion – cannot remember simple things, complete simple/routine tasks.
• Irritability – a change in temperament.
• Belligerence – easily frustrated, compounded by the confusion and irritability.
• Lightheadedness
• In-coordination
• Fatigue – in excess of what would be anticipated.
• Paradoxical chills – goose bumps and shivering in the face of high environmental temperature (an ominous sign).

If you or some one else is exhibiting these symptoms:

1. Stop the activity immediately.
2. Move to a cool (shaded) area.
3. Get some fluid (water, sports drink, IV).
4. Contact a health professional or your sport safety certified coach.

So where do we go from here?

In hindsight, most cases of heat related-illness and dehydration syndromes could have been prevented and should have been predicted. With a working knowledge of heat-related illness and dehydration syndromes, a moderate level of suspicion and a little common sense, everyone can get through two-a-days safely (even in the dog days of August).