What is heat stroke

Heat stroke is the most serious heat-related illness that is caused by your body overheating, usually as a result of prolonged exposure to or physical exertion in high temperatures ¹. The condition is most common in the summer months.

Heat stroke occurs when your body becomes unable to control its temperature: your body’s temperature rises rapidly, the sweating mechanism fails and your body is unable to cool down ². Your body’s temperature may rise to 104°F (40°C) or higher within 10 to 15 minutes.

• Heat stroke can cause death or permanent disability if emergency treatment is not provided !
  
• Untreated heatstroke can quickly damage your brain, heart, kidneys and muscles. The damage worsens the longer treatment is delayed, increasing your risk of serious complications or death.

What are the signs and symptoms of a heat stroke

• An extremely High body temperature. A core body temperature of 104°F (40°C) or higher, obtained with a rectal thermometer, is the main sign of heatstroke.
• Altered mental state or behavior. Confusion, agitation, slurred speech, irritability, delirium, seizures and coma can all result from heatstroke.
• Alteration in sweating. In heatstroke brought on by hot weather, your skin will feel hot and dry to the touch. However, in heatstroke brought on by strenuous exercise, your skin may feel dry or slightly moist.
• Nausea and vomiting. You may feel sick to your stomach or vomit.
• Flushed skin. Your skin may turn red as your body temperature increases.
• Rapid breathing. Your breathing may become rapid and shallow.
• Racing heart rate. Your pulse may significantly increase because heat stress places a tremendous burden on your heart to help cool your body.
• Headache. Your head may throb.
• Red, hot, and dry skin (no sweating)
• Dizziness
• Unconsciousness

What to do for heat stroke or if you see someone with heat stroke ?

If you see any of these signs, you may be dealing with a life-threatening emergency. Have someone call for immediate medical assistance while you begin cooling the victim.

Do the following:

• Get the victim to a shady area.
• Remove excess clothing.
• Cool the victim rapidly, using whatever methods you can. For example, immerse the victim in a tub of cool water; place the person in a cool shower; spray the victim with cool water from a garden hose; sponge the person with cool water; or if the humidity is low, wrap the victim in a cool, wet sheet and fan him or her vigorously.
• Immerse you or the person with heatstroke in cold water. A bath of cold or ice water has been proved to be the most effective way of quickly lowering your core body temperature. The quicker you can receive cold water immersion, the less risk of death and organ damage.
• Pack you or the person with heatstroke with ice and cooling blankets. Another method is to wrap you in a special cooling blanket and apply ice packs to your groin, neck, back and armpits to lower your temperature.
• Monitor body temperature and continue cooling efforts until the body temperature drops to 101-102°F.
• If emergency medical personnel are delayed, call the hospital emergency room for further instructions.
• Do not give the victim alcohol to drink.
• Get medical assistance as soon as possible. Call your local emergency number !

Is treating heat stroke at home safe ?

Home treatment isn’t enough for heatstroke.

• If you have signs or symptoms of heatstroke, seek emergency medical help.

Others should take steps to cool you off while waiting for emergency help to arrive. Don’t drink any fluids while waiting for medical assistance.

If you notice signs of heat-related illness, lower your body temperature and prevent your condition from progressing to heatstroke. In a lesser heat emergency, such as heat cramps or heat exhaustion, the following steps may lower your body temperature:

• Get to a shady or air-conditioned place. If you don’t have air conditioning at home, go someplace with air conditioning, such as the mall, movie theater or public library.
• Cool off with damp sheets and a fan. If you’re with someone who’s experiencing heat-related symptoms, cool the person by covering him or her with damp sheets or by spraying with cool water. Direct air onto the person with a fan.
• Take a cool shower or bath. If you’re outdoors and not near shelter, soaking in a cool pond or stream can help bring your temperature down.
• Rehydrate. Drink plenty of fluids. Also, because you lose salt through sweating, you can replenish salt and water with some sports drinks. If your doctor has restricted your fluid or salt intake, check with him or her to see how much you should drink and whether you should replace salt.
• Don’t drink sugary or alcoholic beverages to rehydrate. These drinks may interfere with your body’s ability to control your temperature. Also, very cold drinks can cause stomach cramps.

Causes of heat stroke

Heat stroke can occur as a result of:

• Exposure to a hot environment. In a type of heatstroke, called non-exertional (classic) heatstroke, being in a hot environment leads to a rise in core body temperature. This type of heat stroke typically occurs after exposure to hot, humid weather, especially for prolonged periods. It occurs most often in older adults and in people with chronic illness.

• Strenuous activity. Exertional heatstroke is caused by an increase in core body temperature brought on by intense physical activity in hot weather. Anyone exercising or working in hot weather can get exertional heatstroke, but it’s most likely to occur if you’re not used to high temperatures.

In either type of heatstroke, your condition can be brought on by:

• Wearing excess clothing that prevents sweat from evaporating easily and cooling your body
• Drinking alcohol, which can affect your body’s ability to regulate your temperature
• Becoming dehydrated by not drinking enough water to replenish fluids lost through sweating

Risk factors of heat stroke

Anyone can develop heatstroke, but several factors increase your risk:

• Age. Your ability to cope with extreme heat depends on the strength of your central nervous system. In the very young, the central nervous system is not fully developed, and in adults over 65, the central nervous system begins to deteriorate, which makes your body less able to cope with changes in body temperature. Both age groups usually have difficulty remaining hydrated, which also increases risk.

• Exertion in hot weather. Military training and participating in sports, such as football or long-distance running events, in hot weather are among the situations that can lead to heatstroke.

• Sudden exposure to hot weather. You may be more susceptible to heat-related illness if you’re exposed to a sudden increase in temperature, such as during an early-summer heat wave or travel to a hotter climate. Limit activity for at least several days to allow yourself to acclimate to the change. However, you may still have an increased risk of heatstroke until you’ve experienced several weeks of higher temperatures.

• A lack of air conditioning. Fans may make you feel better, but during sustained hot weather, air conditioning is the most effective way to cool down and lower humidity.

• Certain medications. Some medications affect your body’s ability to stay hydrated and respond to heat. Be especially careful in hot weather if you take medications that narrow your blood vessels (vasoconstrictors), regulate your blood pressure by blocking adrenaline (beta blockers), rid your body of sodium and water (diuretics), or reduce psychiatric symptoms (antidepressants or antipsychotics e.g. haloperidol or chlorpromazine). Medications for Parkinson’s disease, because they can inhibit perspiration; tranquilizers such as phenothiazines, butyrophenones, and thiozanthenes; and diuretic medications or “water pills” that affect fluid balance in the body.

• Stimulants for attention-deficit/hyperactivity disorder (ADHD) and illegal stimulants such as amphetamines and cocaine also make you more vulnerable to heatstroke.

• Certain health conditions. Certain chronic illnesses, such as heart or lung disease, might increase your risk of heatstroke. So can being obese, being sedentary and having a history of previous heatstroke.

Complications of heat stroke

Heatstroke can result in a number of complications, depending on how long the body temperature is high. Severe complications include:

• Vital organ damage. Without a quick response to lower body temperature, heatstroke can cause your brain or other vital organs to swell, possibly resulting in permanent damage.
• Death. Without prompt and adequate treatment, heatstroke can be fatal.

Prevention of heat stroke

Remember to keep cool and use common sense. Drink plenty of fluid, replace salts and minerals, wear appropriate clothing and sunscreen, pace yourself, stay cool indoors, schedule outdoor activities carefully, use a buddy system, monitor those at risk, and adjust to the environment.

Heatstroke is predictable and preventable. Take these steps to prevent heatstroke during hot weather:

• Wear loose fitting, lightweight clothing. Wearing excess clothing or clothing that fits tightly won’t allow your body to cool properly.
• Protect against sunburn. Sunburn affects your body’s ability to cool itself, so protect yourself outdoors with a wide-brimmed hat and sunglasses and use a broad-spectrum sunscreen with an SPF of at least 15. Apply sunscreen generously, and reapply every two hours — or more often if you’re swimming or sweating.
• Drink plenty of fluids. Staying hydrated will help your body sweat and maintain a normal body temperature.
• Take extra precautions with certain medications. Be on the lookout for heat-related problems if you take medications that can affect your body’s ability to stay hydrated and dissipate heat.

Never leave anyone in a parked car. This is a common cause of heat-related deaths in children. When parked in the sun, the temperature in your car can rise 20 degrees F (more than 6.7°C) in 10 minutes.

• It’s not safe to leave a person in a parked car in warm or hot weather, even if the windows are cracked or the car is in shade. When your car is parked, keep it locked to prevent a child from getting inside.
• Take it easy during the hottest parts of the day. If you can’t avoid strenuous activity in hot weather, drink fluids and rest frequently in a cool spot. Try to schedule exercise or physical labor for cooler parts of the day, such as early morning or evening.
• Get acclimated. Limit time spent working or exercising in heat until you’re conditioned to it. People who are not used to hot weather are especially susceptible to heat-related illness. It can take several weeks for your body to adjust to hot weather.
• Be cautious if you’re at increased risk. If you take medications or have a condition that increases your risk of heat-related problems, avoid the heat and act quickly if you notice symptoms of overheating. If you participate in a strenuous sporting event or activity in hot weather, make sure there are medical services available in case of a heat emergency.

What should I do if I work in a hot environment ?

Pace yourself. If you are not accustomed to working or exercising in a hot environment, start slowly and pick up the pace gradually. If exertion in the heat makes your heart pound and leaves you gasping for breath, STOP all activity. Get into a cool area or at least in the shade, and rest, especially if you become lightheaded, confused, weak, or faint.

In the hot sun, a wide-brimmed hat will provide shade and keep the head cool. If you must go outdoors, be sure to apply sunscreen 30 minutes prior to going out and continue to reapply according to the package directions. Sunburn affects your body’s ability to cool itself and causes a loss of body fluids. It also causes pain and damages the skin.

How much should I drink during hot weather ?

During hot weather you will need to increase your fluid intake, regardless of your activity level. Don’t wait until you’re thirsty to drink. During heavy exercise in a hot environment, drink enough non-alcoholic cool fluids each hour to maintain normal color and amount of urine output.

Should I take salt tablets during hot weather ?

Do not take salt tablets unless directed by your doctor. Heavy sweating removes salt and minerals from the body. These are necessary for your body and must be replaced. The easiest and safest way to do this is through your diet. Drink fruit juice or a sports beverage when you exercise or work in the heat.

How effective are electric fans in preventing heat-related illness ?

Electric fans may provide comfort, but when the temperature is in the high 90s, fans will not prevent heat-related illness. Taking a cool shower or bath or moving to an air-conditioned place is a much better way to cool off. Air conditioning is the strongest protective factor against heat-related illness. Exposure to air conditioning for even a few hours a day will reduce the risk for heat-related illness. Consider visiting a shopping mall or public library for a few hours.

What are heat cramps and who is affected ?

Heat cramps are muscle pains or spasms – usually in the abdomen, arms, or legs – that may occur in association with strenuous activity. People who sweat a lot during strenuous activity are prone to heat cramps. This sweating depletes the body’s salt and moisture. The low salt level in the muscles causes painful cramps. Heat cramps may also be a symptom of heat exhaustion. If you have heart problems or are on a low-sodium diet, seek medical attention for heat cramps.

What should I do if I have heat cramps ?

If medical attention is not necessary, take the following steps:

• Stop all activity and sit quietly in a cool place.
• Drink clear juice or a sports beverage.
• Do not return to strenuous activity for a few hours after the cramps subside because further exertion may lead to heat exhaustion or heat stroke.
• Seek medical attention for heat cramps if they do not subside in 1 hour.

Heat Stroke vs Heat Exhaustion

Heatstroke is a life-threatening illness in which body temperature may rise above 104° F in minutes; symptoms include dry skin, rapid, strong pulse and dizziness.

• Heat stroke can cause death or permanent disability if emergency treatment is not provided !

What is heat exhaustion ?

Heat exhaustion is a milder form of heat-related illness that can develop after several days of exposure to high temperatures and inadequate or unbalanced replacement of fluids ². Those most prone to heat exhaustion are elderly people, those with high blood pressure, and those working or exercising in a hot environment.

What are the warning signs of heat exhaustion ?

The warning signs of heat exhaustion include the following:

• Heavy sweating
• Paleness
• Muscle cramps
• Tiredness
• Weakness
• Dizziness
• Headache
• Nausea or vomiting
• Fainting

The skin may be cool and moist. The pulse rate will be fast and weak, and breathing will be fast and shallow. If heat exhaustion is untreated, it may progress to heat stroke. See medical attention if symptoms worsen or last longer than one hour.

What steps can be taken to cool the body during heat exhaustion ?

• Drink cool, nonalcoholic beverages.
• Rest.
• Take a cool shower, bath, or sponge bath.
• Seek an air-conditioned environment.
• Wear lightweight clothing.

1. Heatstroke. https://www.mayoclinic.org/diseases-conditions/heat-stroke/symptoms-causes/syc-20353581[↩]
2. Frequently Asked Questions (FAQ) About Extreme Heat. https://www.cdc.gov/disasters/extremeheat/faq.html[↩][↩]