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C A D E R
The body is a chemical machine that produces heat as it works.  The harder it works - the more heat it produces.   The bod...
Factors that can increase heat stress. <ul><li>Metabolic rate. </li></ul><ul><li>Environment. </li></ul><ul><li>Clothing. ...
Heat is produced and lost as the body regulates its core temp’.   It does this by. <ul><li>Radiation  50% </li></ul><ul><l...
Why does it occur? <ul><li>Anything that interferes with the body’s regulatory mechanism will reduce its effectiveness. </...
Environment. <ul><li>Humidity. </li></ul><ul><li>Ambient temperature. </li></ul><ul><li>Length of exposure. </li></ul><ul>...
P.P.E. <ul><li>Heat loss with full P.P.E. </li></ul><ul><li>Radiation  (50%)  0 </li></ul><ul><li>Convection  (25%)  0 </l...
What are the effects? <ul><li>Psychological.  </li></ul><ul><li>Physiological. </li></ul>
Psychological. <ul><li>Anxiety - up. </li></ul><ul><li>Cognitive skills - down. </li></ul><ul><li>Mental confusion - incre...
Physiological . <ul><li>Work rate - increases. </li></ul><ul><li>Performance - drops. </li></ul><ul><li>Manipulative skill...
Heat exhaustion . <ul><li>Caused by excessive sweat loss. </li></ul><ul><li>Hot fire instructors can lose over </li></ul><...
Salt Deficiency. <ul><li>Can cause - </li></ul><ul><li>Cramps. </li></ul><ul><li>Headaches. </li></ul><ul><li>Nausea. </li...
Heat Faint (syncope). <ul><li>Causes  - </li></ul><ul><li>Skin blood vessels fill with blood. </li></ul><ul><li>Excessive ...
Heat Stroke. <ul><li>A very serious disorder where the temperature regulating mechanism ceases to function. </li></ul><ul>...
Treatment - Heat Exhaustion. <ul><li>Remove from hot / humid environment </li></ul><ul><li>Cool body - hang loose, etc. </...
Treatment - Heat Induced Faint. <ul><li>Treat for Heat Exhaustion. </li></ul><ul><li>Plus </li></ul><ul><li>Impending fain...
Treatment - Heat Stroke. <ul><li>Treat for Heat Exhaustion. </li></ul><ul><li>Cool with sprays, hand cooling, etc. </li></...
Current Prevention and Treatment <ul><li>Hand cooling. </li></ul><ul><li>Fluid management. </li></ul><ul><li>Oxygen and Fi...
Current Prevention and Treatment <ul><li>Rotation of staff. </li></ul><ul><li>Limited exposure. </li></ul><ul><li>Superior...
There are many ways to help avoid heat stress. <ul><li>Fitness. </li></ul><ul><li>Acclimatisation. </li></ul><ul><li>Reduc...
Cardiovascular  Efficiency Regular exercise improves efficiency of the heart muscle Average heart rate 72 - 76 beats per m...
The Coronary Artery / Atherosclerosis Increases in arterial blood pressure change and damage the inside of the arterial wa...
Normal Decline in Cardiopulmonary Capacity with Age VO2 Max, ml/kg/min Age, years 20  30  40  50  60  70  80  90 0 10 20 3...
 
 
 
 
Hydration. <ul><li>Dehydration impairs work performance and increases chances of Heat Stress. </li></ul><ul><li>Drinking r...
Diuretics. <ul><li>Definition -  A drug that increases the volume of urine produced by promoting excretion of salts and wa...
Replacing Lost Fluid <ul><li>Water will replace lost fluid. </li></ul><ul><li>Drinking too quickly will flood the system a...
Hot Fire Exercise, <ul><li>Total Time = 117 minutes </li></ul><ul><li>Exercise Time = 55.5 minutes </li></ul><ul><li>Expos...
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Physicological demands on firefighters

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Physicological demands on firefighters

  1. 1. C A D E R
  2. 2. The body is a chemical machine that produces heat as it works. The harder it works - the more heat it produces. The body regulates this heat to maintain an optimum temperature of 37 o C. Any deviation from this optimum will reduce performance and lead to heat stress..
  3. 3. Factors that can increase heat stress. <ul><li>Metabolic rate. </li></ul><ul><li>Environment. </li></ul><ul><li>Clothing. </li></ul><ul><li>Fitness. </li></ul><ul><li>Age. </li></ul>
  4. 4. Heat is produced and lost as the body regulates its core temp’. It does this by. <ul><li>Radiation 50% </li></ul><ul><li>Convection 25% </li></ul><ul><li>Evaporation 10% </li></ul><ul><li>Vaporisation 15% </li></ul>
  5. 5. Why does it occur? <ul><li>Anything that interferes with the body’s regulatory mechanism will reduce its effectiveness. </li></ul><ul><li>Environment. </li></ul><ul><li>PPE. </li></ul>
  6. 6. Environment. <ul><li>Humidity. </li></ul><ul><li>Ambient temperature. </li></ul><ul><li>Length of exposure. </li></ul><ul><li>Convection currents. </li></ul><ul><li>Radiation. </li></ul><ul><li>Reduce these to a minimum . </li></ul>
  7. 7. P.P.E. <ul><li>Heat loss with full P.P.E. </li></ul><ul><li>Radiation (50%) 0 </li></ul><ul><li>Convection (25%) 0 </li></ul><ul><li>Evaporation (10%) 0 </li></ul><ul><li>Vaporisation (15%) Some* </li></ul><ul><li>*B.A. restricts this . </li></ul>
  8. 8. What are the effects? <ul><li>Psychological. </li></ul><ul><li>Physiological. </li></ul>
  9. 9. Psychological. <ul><li>Anxiety - up. </li></ul><ul><li>Cognitive skills - down. </li></ul><ul><li>Mental confusion - increases. </li></ul><ul><li>Heat effect - underestimated. </li></ul><ul><li>Personal capabilities - overestimated. </li></ul>
  10. 10. Physiological . <ul><li>Work rate - increases. </li></ul><ul><li>Performance - drops. </li></ul><ul><li>Manipulative skills - deteriorate. </li></ul><ul><li>Fatigue. </li></ul><ul><li>These can lead to the following medical conditions </li></ul><ul><li>Heat Stress, Heat Exhaustion, Heat Stroke </li></ul>
  11. 11. Heat exhaustion . <ul><li>Caused by excessive sweat loss. </li></ul><ul><li>Hot fire instructors can lose over </li></ul><ul><li>3 litres of sweat in one exercise. </li></ul><ul><li>This may lead to loss of body salt </li></ul><ul><li>(electrolyte). </li></ul><ul><li>Note - body temperature remains normal </li></ul><ul><li>+ or - 0.5 0C. </li></ul>
  12. 12. Salt Deficiency. <ul><li>Can cause - </li></ul><ul><li>Cramps. </li></ul><ul><li>Headaches. </li></ul><ul><li>Nausea. </li></ul><ul><li>Collapse. </li></ul>
  13. 13. Heat Faint (syncope). <ul><li>Causes - </li></ul><ul><li>Skin blood vessels fill with blood. </li></ul><ul><li>Excessive sweating reduces blood volume. </li></ul><ul><li>Working muscles compete for limited blood supply. </li></ul><ul><li>Effect </li></ul><ul><li>Less blood/ oxygen reaches brain. </li></ul><ul><li>Fainting can occur. </li></ul><ul><li>Note - core body temp’ remains under control. </li></ul>
  14. 14. Heat Stroke. <ul><li>A very serious disorder where the temperature regulating mechanism ceases to function. </li></ul><ul><li>Body is hot and dry. </li></ul><ul><li>Core body temperature may reach </li></ul><ul><li>41 - 44 0 C </li></ul><ul><li>Potentially fatal . </li></ul>
  15. 15. Treatment - Heat Exhaustion. <ul><li>Remove from hot / humid environment </li></ul><ul><li>Cool body - hang loose, etc. </li></ul><ul><li>Give fluids. </li></ul><ul><li>Rest. </li></ul>
  16. 16. Treatment - Heat Induced Faint. <ul><li>Treat for Heat Exhaustion. </li></ul><ul><li>Plus </li></ul><ul><li>Impending faint. </li></ul>
  17. 17. Treatment - Heat Stroke. <ul><li>Treat for Heat Exhaustion. </li></ul><ul><li>Cool with sprays, hand cooling, etc. </li></ul><ul><li>Hospitalise. </li></ul>
  18. 18. Current Prevention and Treatment <ul><li>Hand cooling. </li></ul><ul><li>Fluid management. </li></ul><ul><li>Oxygen and First Aid. </li></ul><ul><li>Layering. </li></ul><ul><li>Hang loose (with PPV). </li></ul><ul><li>2 hr break between wears (students). </li></ul><ul><li>1 hot wear per day (instructors).* </li></ul>
  19. 19. Current Prevention and Treatment <ul><li>Rotation of staff. </li></ul><ul><li>Limited exposure. </li></ul><ul><li>Superior kit.( Use of Cool Vests ) </li></ul><ul><li>Hang loose (with PPV). </li></ul><ul><li>2 hr break between wears (students). </li></ul><ul><li>1 hot wear per day (instructors).* </li></ul>
  20. 20. There are many ways to help avoid heat stress. <ul><li>Fitness. </li></ul><ul><li>Acclimatisation. </li></ul><ul><li>Reduce exposure. </li></ul><ul><li>Hydration. </li></ul>
  21. 21. Cardiovascular Efficiency Regular exercise improves efficiency of the heart muscle Average heart rate 72 - 76 beats per minute Extremely fit people may be lower than 40 beats per minute Regular aerobic exercise increases the size of the heart muscle and the capacity of its chambers also increases by as much as 30% Therefore, the heart of an active person is much more efficient in delivering blood and oxygen to body tissues
  22. 22. The Coronary Artery / Atherosclerosis Increases in arterial blood pressure change and damage the inside of the arterial wall. The wall may become thicker while the space which transports blood becomes smaller (vascular hypertrophy) A fatty build up called plaque develops in the damaged arterial wall, clogging the flow of blood (atherosclerosis). Blood clots form more easily and become dangerous if dislodged
  23. 23. Normal Decline in Cardiopulmonary Capacity with Age VO2 Max, ml/kg/min Age, years 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 1 3 5 7 9 11 13 15 17
  24. 28. Hydration. <ul><li>Dehydration impairs work performance and increases chances of Heat Stress. </li></ul><ul><li>Drinking regime. </li></ul><ul><li>Water alone will lead to voluntary dehydration. </li></ul><ul><li>Carbohydrate drinks - less than 8%. </li></ul>
  25. 29. Diuretics. <ul><li>Definition - A drug that increases the volume of urine produced by promoting excretion of salts and water from the kidneys. </li></ul><ul><li>Caffeine - Tea and Coffee. </li></ul><ul><li>Alcohol. </li></ul><ul><li>Prescribed drugs. </li></ul>
  26. 30. Replacing Lost Fluid <ul><li>Water will replace lost fluid. </li></ul><ul><li>Drinking too quickly will flood the system and though some water will be absorbed the bulk will be flushed through the kidneys to the bladder. </li></ul><ul><li>By adding a little carbohydrate and mineral salts, fluid can be absorbed more rapidly into the system. Too much and the process will slow down. </li></ul><ul><li>Better to drink slowly and often. </li></ul><ul><li>Better still, always keep your fluid levels topped up by drinking water regularly. </li></ul>
  27. 31. Hot Fire Exercise, <ul><li>Total Time = 117 minutes </li></ul><ul><li>Exercise Time = 55.5 minutes </li></ul><ul><li>Exposure Time = 17 minutes </li></ul><ul><li>Demand = 93 </li></ul><ul><li>Heat = 90 </li></ul><ul><li>Last Wear = 1 day </li></ul><ul><li>Sweat Loss = 3.04 Litres </li></ul><ul><li>Fluid Intake = 1.67 Litres </li></ul><ul><li>Capable of rescue at end = NO! </li></ul>

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