Environmental Considerations

1
Environmental Considerations

• PED 477 Spring 08

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Heat Illness is Preventable

• Heat illness can significantly reduce level of
  performance
• Heat stroke the most severe form of heat illness

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Heat Illness is Preventable

• ATCs must guard against dehydration heat
  illness
• Comprehensive knowledge is critical

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Science of Temperature Regulation

• Heat regulation
• 1. Hyperthermia
• 2. Thermoregulation
• 3. Hypothalamus

5
Heat Gain vs. Heat Loss

• Metabolic
• Radiation
• Conduction
• Convection
• Evaporation (sweating)

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Metabolism

• Energy material transformations in living cells
• Activity increase
• Heat production

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Radiation

• Electromagnetic waves projected or absorbed by
  the body
• Effective when skin temp gt environment

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Conduction

• Heat transfer between solids or solids liquids

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Convection

• Transfer to air current moving around the body

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Evaporation

• The MOST important mechanism for losing heat
• Most effective means
• Sweating can provide more than 80 of heat loss
• Warmer environment gt dependence on evaporative
  heat loss, thus on sweating

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Evaporation

• Sweating does NOT cause heat loss
• Evaporation must occur
• Role of humidity??
• Limits of efficient evaporation?

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Can it get too hot to exercise?

• Tools of the trade sling psychrometer

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Relative Humidity

• Air H2O
• --------------------
• Air T

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Temperature Humidity
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Sweat Rates Determined by

• Athletes size
• Acclimitization
• Fitness
• Hydration status
• Environment
• Clothing
• Type of exercise

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Sweat Rates

• 2 qt. Sweat/hour
• 4 lb. Of body weight

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Sweating Good Bad

• Natural response for thermoregulation
• Leads to dehydration
• Dehydration impairs physiological function
• Lean athlete typically 65 H20

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Importance of Water

• Helps control temperature of working muscles
  vital organs
• 1. Muscles 75 H2O
• 2. Blood 80 H2O
• Essential for cell functioning
• Medium for nearly all body metabolism

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Heat Acclimitization

• 2-4 hours / day
• 10 days
• Benefits
• improve sweating
• mechanism
• decrease HR

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Athletic Participation inCold Weather

• Heat Loss
• 4 Mechanisms
• Respiration

• Heat Gain
• (or prevention of loss)
• Vasoconstriction
• Metabolic rate increase
• Muscle contraction
• Hormonal response

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Wind Chill
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Local Conditions

• Skin appearance
• Progresses from
• Cold / dry / blue
• Red / swollen

• Bronchospasm
• Asthma
• Typical cold day RH?

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Frostbite

• Sx and signs
• Tissue firmness?
• Color
• Red white black
• Waxy / shiny
• Care
• Warm not hot
• Care of skin?
• Depth of injury?

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Cold Risks

• Population
• Women
• Children / Elderly
• Circulatory Compromise
• Metabolism
• Poor Nutrition

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Hypothermia Prevention

• Layering
• Clothing composition
• Cotton?
• Breathability
• Response to saturation
• Wind?
• Core loss areas
• Extremities

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Lightning

• Determine safe distance
• Monitor
• Flash-bang
• Choose safe shelter
• What things are safe?
• What if you cant seek shelter?
• When to resume?
• What if struck?

Do You Have a Plan???????