HEAT INJURY PREVENTION HOT WEATHER REVIEW

1. HEAT INJURY PREVENTIONHOT WEATHER REVIEW Arizona Army Aviation Support Facility #1

2. REFERENCES AR 40-5 FM 21-20-1 FM 3-04.301 FM 21-76

3. WHY IS HEAT PREVENTION IMPORTANT • Combat capability is contingent upon the ability to adapt to the environment • The body can survive only at a narrow range of core temperatures

4. HOW THE BODY RELEASES HEAT • Radiation: transfer of heat from a hotter object to a cooler object though space by radiant energy • Conduction: transfer of heat from molecule to molecule of adjacent objects

5. HEAT RELEASE CONTINUED • Convection: transfer of heat in liquids or gases in which molecules are free to move • Evaporation: heat lose involves the changing of a substance from its liquid state to its gaseous state. Evaporation is the most effective means of body heat loss.

6. INFLUENCING FACTORS • Environmental temperature above 82° • Temperature of surrounding objects • Sun’s radiant heat • Relative humidity above 50% • Air movement • Amount and type of clothing worn • Heat produced by the body • Availability of drinking water

7. EVAPORATION LIMITS • Relative humidity is the factor that most limits evaporation. • At 100% relative humidity evaporation provide virtually no heat loss. (see chart on next slide)

9. TYPES OF HEAT INJURIES • Heat cramps • Heat exhaustion • Heat stroke

10. HEAT CRAMPS INFORMATION • Painful contractions of the muscles in the limbs, abdomen, or back. • Mildest form of heat injury • Heat exhaustion may be present • Body temperature may be normal

11. HEAT CRAMPS CAUSE • Excessive loss of salt through perspiration.

12. HEAT CRAMPS TREATMENT • Move soldier to a shady area and loosen clothing if possible • Slowly give large amounts of cool water • Pour water on soldier and fan • Elevate legs for exhaustion • Watch soldier, if possible release from strenuous activity • Get medical help if symptoms continue

13. HEAT EXHAUSTION INFORMATION • Skin is cool and moist; pulse is rapid and blood pressure may be low • Other symptoms are profuse sweating, headaches, tingling in hands and feet, paleness, difficulty breathing, irregular heart beat, loss of appetite, nausea and vomiting • Oral temperature may be lower than normal if the person is hyperventilating

14. HEAT EXHAUSTION INFORMATION CONT. • Trembling, weakness, lack of coordination and a slight clouding of senses to momentary loss of consciousness complete the classic picture • Avoided by proper work/rest cycles and good hydration

15. HEAT EXHAUSTION CAUSE • Electrolyte imbalance due to salt loss • Low blood pressure caused by water loss

16. HEAT EXHAUSTION TREATMENT • Move soldier to a shady area and loosen clothing if possible • Slowly give large amounts of cool water • Pour water on soldier and fan • Elevate legs for exhaustion • Watch soldier, if possible release from strenuous activity • Intravenous treatment may be required • Get medical help if symptoms continue

17. !!!!CAUTION!!!! Those that have suffered from heat exhaustion are ‘fragile’ and can have another episode easily

18. HEAT STROKE INFORMATION • A medical emergency and death rate is high • Early signs are headache, dizziness, delirium, weakness, nausea, vomiting and excessive warmth • Skin is usually hot, red and dry • Body temperature may be as high as 106 F

19. HEAT STROKE INFORMATION • The casualty may go through heat cramps or heat exhaustion; a sudden collapse and loss of consciousness followed by coma and convulsions may occur • Sweating may or may not be present • Avoided by proper work/rest cycles and full hydration

20. HEAT STROKE CAUSE • The failure of the body to maintain its temperature within specified upper limits • Inadequate sweating is a factor

21. HEAT STROKE TREATMENT • Lower the casualty’s body temperature as soon as possible • Pour water on the casualty and his clothes • Put the casualty in the shade, elevate his legs, get him off any hot surfaces and have him slowly drink water if possible • Seek immediate medical assistance and evacuation

22. !!!!CAUTION!!!! Heat stroke casualties are more susceptible to a second attack

23. PERFORMANCE IMPAIRMENT Generally, increases in body temperatures have the following effects: • Error rates increase • Short term memory becomes less reliable. • Perceptual and motor skills slow

24. Effects of Increases in body temperature on performance MENTALEFFICIENCY WORK DONE ERRORS 98.6 100.2 100.3 101 BODY TEMPERATURE (° F)

25. PREDISPOSING FACTORS Acclimatization; 7-14 days, 2 hours a day

26. PREDISPOSING FACTORS Overweight and fatigue

27. PREDISPOSING FACTORS Heavy meals and hot food

28. PREDISPOSING FACTORS Alcohol and drugs • Drugs that inhibit sweating are atropine, antihistamines, some tranquilizers, cold medicine and some antidiarrheal medicines

29. PREDISPOSING FACTORS Fevers • Many immunizations produce fevers

30. PREDISPOSING FACTORS Tight clothing

31. PREVENTING HEAT INJURIES • Replace water loss; by sweating a person can lose more than 1 quart per hour • Drink small amounts of water frequently regardless of thirst • Use heat injury prevention chart as a guide • Provide adequate water at all times

32. PREVENTING HEAT INJURIES • Maintain acclimatization • Begin acclimatization with first exposure • Continue with two 50 minutes periods daily • Limit intensity and time of exposure for those not acclimatized • Acclimatization can be lost if remove from the hot environment for 1 month

33. PREVENTING HEAT INJURIES Maintain good physical condition

34. PREVENTING HEAT INJURIES • Establish a good work/rest schedule; must be tailored to fit climate, physical condition of personnel and military situation • Work in cooler hours • Avoid working in direct sunlight • Slowly increase exposure to those becoming acclimatized • Use heat injury prevention chart as a guide

35. !!!CAUTION!!! Overexertion can cause heat injuries at temperatures lower than 75 degrees F on the WBGT index

36. PREVENTING HEAT INJURIES • Use proper clothing to protect yourself • Loose clothing • Wear least amount when possible • Obtain the WBGT • Add 10 degrees to WBGT when wearing body armor or MOPP

37. REVIEW

38. QUIZ Click on the link below to access the Heat Injury Prevention Quiz http://ang.quizstarpro.com Log-in and Click “Search” Tab Class Name = Heat Injury Prevention