Heat Intolerance Problems

1. Heat Intolerance Problems Kambiz Behzadi, M.D. Orthopaedic Surgeon Fremont/Pleasanton

2. What Causes Heat Related Illness? Body’s failure to keep itself cool Sweat/Evaporation releases heat Humidity impairs release of heat Increased body temperature Heat Illness

3. Heat Intolerance > 300 people die of heat related illness in U.S. Heightened awareness in athletes Identify athletes at risk Not a disease Accident waiting to happen

4. Heat Intolerance Heat Stroke can occur in best athletes Korey Stringer, Vikings, professional Estrate Autin, Florida, college

5. Heat Intolerance Preseason Football, Marathon, Soccer Mild to Fatal High Temperature + High Humidity Preventable awareness, recognition, treatment

6. Hypothalamus Body’s Thermostat As temperature hypothalamus responds: 1. Increase blood flow to skin 2. Increase sweating

7. Temperature Regulation Conduction: jumping into the pool Convection: standing in front of fan Evaporation: water from liquid to gas Radiation: electromagnetic heat waves

8. Temperature Regulation Conduction

9. Temperature Regulation Convection

10. Temperature Regulation Sweating & Evaporation

11. Temperature Regulation Radiation

12. Sweating/Evaporation In hot a environment, Evaporation becomes the Primary source of Heat Dissipation Humidity decreases our ability to get rid of Heat

13. Exercise Work + Heat Heat increases core body temperature Warm blood bathes the hypothalamus Blood diverted from warm core to cool shell (conduction, convection, radiation) Sweat glands release hypotonic saline solution (sweat) evaporation

14. Physiology Exercise work + heat Hypothalamus Blood Flow Skin Sweat

15. Hot Environment Sweat/Evaporation Conduction Convection Radiation

16. Exercise in Heat Two Demands on Circulatory System Blood (Nutrients and Oxygen) to Working Muscle Blood to Skin to Cool Body

17. Heat and Exercise Muscle G.I. Tract Kidney Circulatory System Liver Brain Skin

18. Early Heat Intolerance Shock: Weak pulse, low blood pressure, dizziness, syncope, headache, nausea, vomiting, lack of appetite, weakness Temperature below 102 F or 39 C

19. Stressed Out Circulatory System Dehydration & Fluid Loss Worsening State of Shock

20. Heat Stress + Exercise Overwhelmed Cardiovascular System Heat Exhaustion

21. Heat Stroke Break down cooling mechanism Increase core body temperature + Shock Damage to cells in body Multi-system failure Death

22. Heat Intolerance Problems Heat Syncope Heat Cramps Heat Exhaustion Heat Stroke

23. Heat Syncope Athlete stands still after exercise Pooling of blood in extremities Light-headed, dizzy, faint Core body temperature is normal Lie on ground, shaded area, legs elevated Oral fluids usually not required Recovery rapid

24. Heat Syncope Treatment

25. Heat Cramps Painful contractions large muscle groups ( legs, abdomen) Dehydration & Loss of balance between salt and water in muscle Treatment: 1. Rest and Passive stretch2. Fluid replacement (water, sports drink) Prevention: Adequate hydration before and throughout exercise

26. Heat Cramps Treatment

27. Heat Exhaustion Most common form of heat intolerance Fatigue, weakness, sweating, nausea, diarrhea, mental status normal to slightly impaired Symptoms of mild shock Temperature < 102 F or 39 C

28. Heat Exhaustion Treatment Lie in cool, shaded area Fluid replacement IV Fluids Do not allow return to vigorous activity until normal body weight is reached

29. Heat Stroke True Medical Emergency Hyperthermia (Temp>105F or >40C) Failure of Thermoregulatory Mechanism Central Nervous System Dysfunction Second most common cause of death in U.S. athlete

30. Animals Built-in Protective Mechanism

31. Exercise + Heat Mild Shock Fluid Loss and Shock Dehydration Overwhelming Temperature Heat regulatory Mechanism Metabolism

32. Diagnosis Heat Stroke: Rectal Temp > 105 F Aggressiveness Irritability Emotional Instability and hysteria Apathy Disorientation Unsteady gait Hot, dry skin Unconsciousness

33. Treatment Heat Stroke Call Ambulance Remove clothing Immerse in cool/iced water bath Cover wet sheets and compress+fan Airway, Oxygen, Rehydration Support Multi-organ failure

34. Prevention Acclimatization: body’s adaptation to heat stress, and increased capacity to work in high temperature and humidity 7 days to several weeks 30 minutes 2 hours Lower resting body temperature Increased plasma volume Lower threshold for sweating

35. Prevention Practice in early morning or late afternoon Night games early in season Uniforms light weight, porous, light in color Sleeves short and socks low Much skin exposed to air

36. Prevention Hydration is key Free intake of fluids during games Regular fluid breaks no less than every half hour 1 pint (2 cups) for each 1 pound sweat lost 10 oz. Every 30 minutes Only 50% fluid loss made up by thirst (encourage fluid intake between and during sessions) Events < 90 min, electrolyte replacement usually unnecessary

37. Prevention Glucose concentration < 5% to 8% Dilute twofold 10% glucose (soft drinks and juices) cause stomach cramps, nausea, diarrhea, slow gastric emptying Fructose (fruits) absorbed slowly and causes G.I. distress

38. Prevention Sports drinks Replacement glycogen in (muscle and liver) in exercise lasting > 90 minutes Dilute solution Sodium and Glucose increase absorption of water in small intestine

39. Prevention Cumulative Hypohydration Weigh before and after each practice No player should be allowed to return to play until fluid loss is replaced and normal weight is achieved

40. Electrolyte Make-up Goal to replace sweat that has evaporated Sweat = water + small concentration of salts and other electrolytes Concept: Sport drink = Sweat Evaporated sweat replaced before next exercise Normal diet replaces lost electrolytes Electrolytes in drinks increase absorption of water