What happens when you get heat stroke? - Douglas J. Casa

1,764,410 views ・ 2014-07-21

TED-Ed


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In 1985, 16-year-old Douglas Casa,
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ran the championship 10,000 meter track race at the Empire State Games.
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Suddenly, with just 200 meters to go, he collapsed,
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got back up and then collapsed again on the final straightaway,
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with his body temperature at dangerous levels.
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He had suffered an exertional heat stroke.
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Fortunately, with immediate and proper treatment,
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he survived the potentially fatal episode
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and has since helped save 167 people in similar circumstances.
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From ancient soldiers on the battlefield
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to modern day warriors on the gridiron,
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exertional heat stroke, or sunstroke, has long been a serious concern.
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And unlike classical heat stroke, which affects vulnerable people
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such as infants and the elderly during heat waves,
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exertional heat stroke is caused by intense exercise in the heat,
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and is one of the top three killers of athletes and soldiers in training.
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When you exercise, nearly 80% of the energy you use
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is transformed into heat.
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In normal circumstances, this is what's known as
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compensable heat stress.
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And your body can dissipate the heat as quickly as it's generated
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through cooling methods like the evaporation of sweat.
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But with uncompensable heat stress,
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your body is unable to lose enough heat
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due to overexertion or high temperatures in humidity,
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which raises your core temperature beyond normal levels.
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This causes the proteins and cell membranes to denature,
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creating cells that no longer function properly
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and begin to leak their contents.
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If these leaky cells proliferate through the body,
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the results can be devastating.
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Including liver damage, blood clot formation in the kidneys,
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damage to the gastrointestinal tract and even the failure of vital organs.
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So how do you diagnose an exertional heat stroke?
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The main criterion is a core body temperature greater than 40 degrees Celsius
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observed along with physical symptoms
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such as increased heart rate, low blood pressure and rapid breathing
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or signs of central nervous system disfunction
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such as confused behavior, aggression or loss of consciousness.
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The most feasible and accurate way to assess core body temperature
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is with a rectal thermometer
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as other common temperature-taking methods are not accurate in these circumstances.
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As far as treatment goes,
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the most important thing to remember is cool first, transport second.
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Because the human body can withstand a core temperature above 40 degrees Celsius
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for about 30 minutes before cell damage sets in,
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it's essential to initiate rapid cooling on site
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in order to lower it as quickly as possible.
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After any athletic or protective gear has been removed from the victim,
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place them in an ice water tub while stirring the water
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and monitoring vitals continuously.
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If this is not possible,
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dousing in ice water and applying wet towels over the entire body can help.
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But before you start anything, emergency services should be called.
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As you wait, it's important to keep the victim calm
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while cooling as much surface area as possible
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until emergency personnel arrive.
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If medical staff are available on site, cooling should continue
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until a core temperature of 38.9 degrees Celsius is reached.
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The sun is known for giving life,
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but it can also take life away if we're not careful,
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even affecting the strongest among us.
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As Dr. JJ Levick wrote of exertional heat stroke in 1859,
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"It strikes down its victim with his full armor on.
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Youth, health and strength oppose no obstacle to its power."
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But although this condition is one of the top three leading causes of death in sports,
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it has been 100% survivable with proper care.
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