David Baxter PhD
Late Founder
How to recognize and treat heat stroke
By Angela Mulholland, CTV Health
July 7, 2010
With much of central Canada in the grips of a heat wave, the people at St. John Ambulance would like to remind you how to recognize the signs of different heat-related illnesses, and what to do.
Heat Cramps
Heat cramps are marked by painful muscle cramps, primarily in the legs and abdomen and excessive sweating. This is usually caused by losing too much water and salt through sweating, often following excessive physical activity in hot weather. Heat cramps are not serious and can be reversed with some basic first aid.
More serious than heat cramps, the symptoms of heat exhaustion include: excessive sweating, dilated pupils, complaints of dizziness, blurred vision, headaches, and cramps. The victim may also have cool, clammy skin, a weak rapid pulse and rapid shallow breathing. They may also vomit or go unconscious.
This is a life-threatening condition. Without immediate action, heatstroke can result in permanent brain damage or death. If heatstroke is suspected, seek medical attention immediately or call 911. Symptoms include: a rapid and full pulse that gets weaker and harder to feel in later stages, noisy breathing, flushed skin, hot and dry skin or hot and sweaty skin (when heatstroke is related to exertion), restlessness, a headache, fatigue, dizziness, nausea, vomiting, convulsions and eventually, unconsciousness.
Why are we so susceptible to heat stroke during muggy, humid days?
The short answer is our skin can't work right. Most of our excess body heat is shed through the skin, when blood brings heat from core tissues to the skin. That's what causes our skin to flush in the heat. When the surrounding air is cool and dry, it is easy for us to get rid of heat, because the cool air around us wicks heat from the skin. But the hotter and more humid it gets, the more difficult it becomes.
If the air is as hot as or hotter than the skin -- about 36?Celsius -- the skin will actually absorb heat from its surroundings. If the air is also really humid, our skin can't cool itself by sweating, because the sweat won't evaporate properly. The heat-regulating mechanisms of the body can eventually become overwhelmed, causing our body temperature to climb dangerously high.
By Angela Mulholland, CTV Health
July 7, 2010
With much of central Canada in the grips of a heat wave, the people at St. John Ambulance would like to remind you how to recognize the signs of different heat-related illnesses, and what to do.
Heat Cramps
Heat cramps are marked by painful muscle cramps, primarily in the legs and abdomen and excessive sweating. This is usually caused by losing too much water and salt through sweating, often following excessive physical activity in hot weather. Heat cramps are not serious and can be reversed with some basic first aid.
First Aid
Ensure the person is put at rest in a cool place and given as much water as possible in small amounts so as not to cause nausea. If the cramps do not subside, seek medical help.
Heat ExhaustionEnsure the person is put at rest in a cool place and given as much water as possible in small amounts so as not to cause nausea. If the cramps do not subside, seek medical help.
More serious than heat cramps, the symptoms of heat exhaustion include: excessive sweating, dilated pupils, complaints of dizziness, blurred vision, headaches, and cramps. The victim may also have cool, clammy skin, a weak rapid pulse and rapid shallow breathing. They may also vomit or go unconscious.
First Aid
Give the victim water to drink, as much as they will take. If they vomit, do not give them anything by mouth and seek medical attention right away. Place them at rest in the shock position in a cool place and remove any excess clothing and loosen clothing around the neck and waist. If they go unconscious, put them in the recovery position and get medical help. Continue monitoring their condition.
Heatstroke (Sun stroke)Give the victim water to drink, as much as they will take. If they vomit, do not give them anything by mouth and seek medical attention right away. Place them at rest in the shock position in a cool place and remove any excess clothing and loosen clothing around the neck and waist. If they go unconscious, put them in the recovery position and get medical help. Continue monitoring their condition.
This is a life-threatening condition. Without immediate action, heatstroke can result in permanent brain damage or death. If heatstroke is suspected, seek medical attention immediately or call 911. Symptoms include: a rapid and full pulse that gets weaker and harder to feel in later stages, noisy breathing, flushed skin, hot and dry skin or hot and sweaty skin (when heatstroke is related to exertion), restlessness, a headache, fatigue, dizziness, nausea, vomiting, convulsions and eventually, unconsciousness.
First Aid
Call for medical assistance. It is critical that the body temperature is lowered as quickly as possible; cover them with a wet sheet and fan them, immerse them in cool not cold water (watch them closely for any changes) or sponge them with cool water particularly in the armpits neck and groin.
Remember, to avoid any of these conditions, it's important to stay hydrated during heat waves if you have to be outside. How much water should you be drinking? If you're working outside in the heat, drink two to four 8-oz glasses of cool fluids each hour. That's about a litre of water an hour. Don't wait until you're thirsty to drink, because your body is already dehydrated by the time it signals thirst to your brain. Call for medical assistance. It is critical that the body temperature is lowered as quickly as possible; cover them with a wet sheet and fan them, immerse them in cool not cold water (watch them closely for any changes) or sponge them with cool water particularly in the armpits neck and groin.
Why are we so susceptible to heat stroke during muggy, humid days?
The short answer is our skin can't work right. Most of our excess body heat is shed through the skin, when blood brings heat from core tissues to the skin. That's what causes our skin to flush in the heat. When the surrounding air is cool and dry, it is easy for us to get rid of heat, because the cool air around us wicks heat from the skin. But the hotter and more humid it gets, the more difficult it becomes.
If the air is as hot as or hotter than the skin -- about 36?Celsius -- the skin will actually absorb heat from its surroundings. If the air is also really humid, our skin can't cool itself by sweating, because the sweat won't evaporate properly. The heat-regulating mechanisms of the body can eventually become overwhelmed, causing our body temperature to climb dangerously high.
