Heat-Related Illness

1. Heat-Related Illness Mark De Carlo, PT, MHA, SCS, ATC Methodist Sports Medicine Center Indianapolis, Indiana

2. Introduction • Heat illness is inherent to physical activity • Heat illness incidence increases with rising temperature and relative humidity • Heat illness is not synonymous with hydration status • Heat illness deaths in football are preventable

3. Traditional Philosophies • Not being able to “take the heat” is a sign of weakness • Restricting water as a disciplinary measurement • Drinking too much water causes cramps • Salt tablets prevent cramps

4. Statistics • Annual Survey of Football Injury Research 1931-2003 • Chaired by Dr. Fred Mueller • 106 total cases of heat stroke which resulted in death • 1960 to 2003 – 101 heat stroke deaths • 1970 – high of 8 heat stroke deaths • 1995 to 2001 – 15 of 21 heat stroke deaths at the high school level • 0 heat stroke deaths in past 2 years

5. Risk Factors

6. History of heat illness Poor heat acclimation Lower fitness level Higher % body fat Dehydration Fever/illness Medications (diuretics, antihistamines) Supplements (ephedra) Highly motivated Reluctance to report problems Intrinsic Risk Factors

7. Intense and prolonged exercise High temperature, humidity, and sun exposure Lack of education and awareness No shade or rest breaks Limited access to fluids No emergency plan Delay in recognition of early warning signs Extrinsic Risk Factors

8. Prevention

9. Hydration • Dehydration occurs when sweat loss exceeds fluid intake • Fluid-replacement should be cold and easily accessible • Thirst is a poor indicator of hydration

10. Hydration • Prehydrate • Drink 16 oz 2 hours prior to activity • Maintain hydration • Drink 6-8 oz for every 15 minutes of intense activity • Rehydrate • Correct fluid loss within 2 hours after activity

11. Monitor Weight Loss • Check weight before and after activity • Match fluid intake to sweat and urine loss • Voluntary drinking replaces only about 50% of body-fluid loss • Maintain less than 2% body-weight change • Replace weight loss with equal amount of fluid • Drink 16 oz for each pound lost

12. Electrolyte Balance • Eat salty foods or add salt to meals and snacks • If activity > 1 hour, include carbohydrates and sodium with fluid • Sports drinks • Avoid salt tablets • With insufficient water, hypertonicity can make dehydration worse

13. Drugs and Supplements • Ephedra • Linked to heart attacks, seizures, and heat stroke • Diuretics • Cause loss of fluids • Antihistamines • Constrict blood vessels • Check side effects of all medications

14. Heat Acclimation • Gradually ramp up outdoor activity • First 2 to 3 days of activity present greatest danger • Acclimatization requires 8 to 12 days for adults, 10 to 14 days for adolescents

15. Clothing and Equipment • Wear loose fitting or moisture-wicking, light colored clothes • Sweat dampened clothes impede evaporation • Avoid cottons or bring an extra change of clothes • Minimize equipment and padding when indicated

16. Environment • Wet Bulb Globe Temperature (WBGT) • Used as an index to modify activity • WBGT = (.1 x Dry Bulb Temp) + (.2 x Black Globe Temp) + (.7 x Wet Bulb Temp)

17. Wet-Bulb Globe Temperature Environment

18. Environment • Sling psychrometer • Can be used to estimate WBGT • Produces dry bulb temperature (DBT) and wet bulb temperature (WBT) • Use DBT and WBT to calculate relative humidity

19. Environment

20. Environment • Modify activity under high risk conditions • Increase length and frequency of rest breaks • Limit intensity and duration of activity • Limit the amount of clothing and equipment • Unlimited and accessible hydration

21. Recognition

22. Heat Illness • Heat illness is traditionally divided into 4 categories • Heat cramps • Heat syncope • Heat exhaustion • Heat stroke • Heat illness is not sequential; there is a lack of continuum between categories • Early recognition of heat illness is more important than differentiating categories of heat illness

23. Early Weakness, fatigue Weak, rapid pulse Dizziness, light headed, fainting Dehydration and cramping Pallor Cool and clammy skin Profuse sweating Severe Nausea, vomiting, diarrhea Skin hot and wet or dry Staggering gait Delirium, confusion Irrational behavior, emotional instability, aggressiveness Loss of consciousness Signs and Symptoms

24. On-Field Recognition • Players • Taking a knee • Cramping • Vomiting • Slow returning to huddle or disengaged from huddle • Going to the wrong sideline • Staggering • Collapse

25. On-Field Recognition • Officials • Flushed or pale face • Resting hands on knees • Altered vision • Confusion about rules, possession, penalties • Incoherent speech • Hyperventilation • Staggering • Collapse

26. Treatment

27. Treatment Guidelines • Heat loss must equal heat gain • Recognize that all stages of heat illness require treatment of fluid replacement and cooling • Take early action • When in doubt, assume heat stroke

28. Early Treatment • Remove from activity to shade or air conditioned facility • Begin fluid replacement • Remove excess clothing and equipment • Cool with fans, ice towels, or ice bags • Monitor vitals and core temperature

29. Severe Treatment • Cool before transport • Remove excess clothing and equipment • Rapid, whole body cooling • Cold water immersion for 20 minutes in small pool or tub is best treatment • 100% success in 252 cases of heat stroke • Ice packs to axilla and groin, cover with ice towels, spray with cold water • Oral fluids if conscious • Monitor rectal temperature

30. Recommendations for Officials • Consult with athletic training staff prior to contest • Utilize official’s time out for heat and humidity to allow extra rest and water breaks • Rule 3-5-1, ART 7 and Case 3.5.7 • Monitor athletes for signs and symptoms • Practice and apply guidelines to yourselves

31. Conclusion • Heat illness death is preventable • Modify activity under high risk conditions • Recognize early signs of heat illness • All categories of heat illness require treatment of hydrating and cooling • Cold water immersion is the best treatment