HEAT INJURY PREVENTION HOT WEATHER REVIEW

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HEAT INJURY PREVENTIONHOT WEATHER REVIEW

• Arizona
• Army Aviation Support Facility 1

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REFERENCES

• AR 40-5
• FM 21-20-1
• FM 3-04.301
• FM 21-76

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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

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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

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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.

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INFLUENCING FACTORS

• Environmental temperature above 82
• Temperature of surrounding objects
• Suns radiant heat
• Relative humidity above 50
• Air movement
• Amount and type of clothing worn
• Heat produced by the body
• Availability of drinking water

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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)

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TYPES OF HEAT INJURIES

• Heat cramps
• Heat exhaustion
• Heat stroke

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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

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HEAT CRAMPS

• CAUSE
• Excessive loss of salt through perspiration.

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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

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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

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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

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HEAT EXHAUSTION

• CAUSE
• Electrolyte imbalance due to salt loss
• Low blood pressure caused by water loss

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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

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!!!!CAUTION!!!!

• Those that have suffered from heat exhaustion
  are fragile and can have another episode easily

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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

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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

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HEAT STROKE

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

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HEAT STROKE

• TREATMENT
• Lower the casualtys 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

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!!!!CAUTION!!!!

• Heat stroke casualties are more susceptible to a
  second attack

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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

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Effects of Increases in body temperature on
performance
MENTAL EFFICIENCY
WORK DONE
ERRORS
98.6
100.2 100.3 101
BODY TEMPERATURE ( F)
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PREDISPOSING FACTORS

• Acclimatization 7-14 days, 2 hours a day

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PREDISPOSING FACTORS

• Overweight and fatigue

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PREDISPOSING FACTORS

• Heavy meals and hot food

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PREDISPOSING FACTORS

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

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PREDISPOSING FACTORS

• Fevers
• Many immunizations produce fevers

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PREDISPOSING FACTORS

• Tight clothing

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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

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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

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PREVENTING HEAT INJURIES

• Maintain good physical condition

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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

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!!!CAUTION!!!

• Overexertion can cause heat injuries at
  temperatures lower than 75 degrees F on the WBGT
  index

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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

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REVIEW
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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