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Heat-related deaths and illness are preventable yet
annually many people succumb to extreme heat. Historically, from
1979 to 1999, excessive heat exposure caused 8,015 deaths in the
United States. During this period, more people in this country
died from extreme heat than from hurricanes, lightning, tornadoes,
floods, and earthquakes combined. In 2001, 300 deaths were caused
by excessive heat exposure.
People suffer heat-related illness
when their bodies are unable to compensate and properly cool themselves.
The body normally cools itself by sweating. But under some conditions,
sweating just isn’t enough. In such cases, a person’s
body temperature rises rapidly. Very high body temperatures may
damage the brain or other vital organs.
Several factors affect
the body’s ability to cool itself during extremely hot weather.
When the humidity is high, sweat will not evaporate as quickly,
preventing the body from releasing heat quickly. Other conditions
related to risk include age, obesity, fever, dehydration, heart
disease, mental illness, poor circulation, sunburn, and prescription
drug and alcohol use.
Because heat-related deaths are preventable,
people need to be aware of who is at greatest risk and what actions
can be taken to prevent a heat-related illness or death. The elderly,
the very young, and people with mental illness and chronic diseases
are at highest risk. However, even young and healthy individuals
can succumb to heat if they participate in strenuous physical activities
during hot weather. Air-conditioning is the number one protective
factor against heat-related illness and death. If a home is not
air-conditioned, people can reduce their risk for heat-related
illness by spending time in public facilities that are air-conditioned.
What Is Extreme Heat?
Temperatures that hover 10
degrees or more above the average high temperature for the region
and last for several weeks are defined as extreme heat. Humid or
muggy conditions, which add to the discomfort of high temperatures,
occur when a “dome” of high atmospheric pressure traps
hazy, damp air near the ground. Excessively dry and hot conditions
can provoke dust storms and low visibility. Droughts occur when
a long period passes without substantial rainfall. A heat wave
combined with a drought is a very dangerous situation.
To protect your health when temperatures are extremely
high, remember to keep cool and use common sense. The following
tips are important:
Drink Plenty of Fluids
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 two to four glasses
(16–32 ounces) of cool fluids each hour.
Warning: If your
doctor generally limits the amount of fluid you drink or has you
on water pills, ask how much you should drink while the weather
Don’t drink liquids that contain caffeine, alcohol,
or large amounts of sugar— these actually cause you to lose
more body fluid. Also avoid very cold drinks, because they can
cause stomach cramps.
Replace Salt and Minerals
Heavy sweating removes
salt and minerals from the body. These are necessary for your body
and must be replaced. If you must exercise, drink two to four glasses
of cool, nonalcoholic fluids each hour. A sports beverage can replace
the salt and minerals you lose in sweat. However, if you are on
a low-salt diet, talk with your doctor before drinking a sports
beverage or taking salt tablets.
Wear Appropriate Clothing and
Wear as little clothing as possible when you are at home.
Choose lightweight, light-colored, loose-fitting clothing. Sunburn
affects your body’s ability to cool itself and causes a loss
of body fluids. It also causes pain and damages the skin. If you
must go outdoors, protect yourself from the sun by wearing a wide-brimmed
hat (also keeps you cooler) along with sunglasses, and by putting
on sunscreen of SPF 15 or higher (the most effective products say “broad
spectrum” or “UVA/UVB protection” on their labels)
30 minutes prior to going out. Continue to reapply it according
to the package directions.
Schedule Outdoor Activities Carefully
If you must be outdoors, try to limit your outdoor activity to
morning and evening hours. Try to rest often in shady areas so
that your body’s thermostat will have a chance to recover.
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 into the shade, and rest, especially if
you become lightheaded, confused, weak, or faint.
Stay Cool Indoors
Stay indoors and, if at all possible,
stay in an air-conditioned place. If your home does not have air
conditioning, go to the shopping mall or public library—even
a few hours spent in air conditioning can help your body stay cooler
when you go back into the heat. Call your local health department
to see if there are any heat-relief shelters in your area. Electric
fans may provide comfort, but when the temperature is in the high
90s, fans will not prevent heatrelated illness. Taking a cool shower
or bath or moving to an air-conditioned place is a much better
way to cool off. Use your stove and oven less to maintain a cooler
temperature in your home.
Use a Buddy System
When working in the
heat, monitor the condition of your co-workers and have someone
do the same for you. Heatinduced illness can cause a person to
become confused or lose consciousness. If you are 65 years of age
or older, have a friend or relative call to check on you twice
a day during a heat wave. If you know someone in this age group,
check on them at least twice a day.
Monitor Those at High Risk
Although any one at any time can suffer from heat-related illness,
some people are at greater risk than others.
• Infants and
children up to four years of age are sensitive to the effects of
high temperatures and rely on others to regulate their environments
and provide adequate liquids.
• People 65 years of age or
older may not compensate for heat stress efficiently and are less
likely to sense and respond to change in temperature.
who are overweight may be prone to heat sickness because of their
tendency to retain more body heat.
• People who overexert
during work or exercise may become dehydrated and susceptible to
• People who are physically ill, especially
with heart disease or high blood pressure, or who take certain
medications, such as for depression, insomnia, or poor circulation,
may be affected by extreme heat.
Visit adults at risk at least
twice a day and closely watch them for signs of heat exhaustion
or heat stroke. Infants and young children, of course, need much
more frequent watching.
Adjust to the Environment
Be aware that any sudden
change in temperature, such as an early summer heat wave, will
be stressful to your body. You will have a greater tolerance for
heat if you limit your physical activity until you become accustomed
to the heat. If you travel to a hotter climate, allow several days
to become acclimated before attempting any vigorous exercise, and
work up to it gradually.
Use Common Sense
Remember to keep cool
and use common sense:
- Avoid hot foods and heavy meals— they
add heat to your body.
- Drink plenty of fluids and replace
salts and minerals in your body.
- Dress infants and children
in cool, loose clothing and shade their heads and faces with
hats or an umbrella.
- Limit sun exposure during mid-day
hours and in places of potential severe exposure such as beaches.
- Do not leave infants, children, or pets in a parked car.
plenty of fresh water for your pets, and leave the water in a
Hot Weather Health Emergencies
short periods of high temperatures can cause serious health problems.
Doing too much on a hot day, spending too much time in the sun
or staying too long in an overheated place can cause heat-related
illnesses. Know the symptoms of heat disorders and overexposure
to the sun, and be ready to give first aid treatment.
Heat stroke occurs when the body is unable to regulate its temperature.
The body’s temperature rises rapidly, the sweating mechanism
fails, and the body is unable to cool down. Body temperature may
rise to 106°F or higher within 10 to 15 minutes. Heat stroke
can cause death or permanent disability if emergency treatment
is not provided.
Recognizing Heat Stroke
Warning signs of heat
stroke vary but may include the following:
- An extremely
high body temperature (above 103°F, orally)
- Red, hot,
and dry skin (no sweating)
- Rapid, strong pulse
What to Do
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.
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
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.
not give the victim fluids to drink.
- Get medical assistance
as soon as possible.
Sometimes a victim’s muscles will
begin to twitch uncontrollably as a result of heat stroke. If
this happens, keep the victim from injuring himself, but do not
place any object in the mouth and do not give fluids. If there
is vomiting, make sure the airway remains open by turning the
victim on his or her side.
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. It is the body’s response
to an excessive loss of the water and salt contained in sweat.
Those most prone to heat exhaustion are elderly people, people
with high blood pressure, and people working or exercising in
a hot environment.
Recognizing Heat Exhaustion
Warning signs of heat exhaustion include
- Heavy sweating
- Muscle cramps
- Nausea or vomiting
The skin may be cool and moist. The victim’s
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. Seek medical attention immediately if any of
the following occurs:
- Symptoms are severe
- The victim has heart
problems or high blood pressure
Otherwise, help the victim to
cool off, and seek medical attention if symptoms worsen or last
longer than 1 hour.
What to Do
Cooling measures that may be effective
include the following:
- Cool, nonalcoholic beverages, as
directed by your physician
- Cool shower, bath,
or sponge bath
- An air-conditioned environment
Heat cramps usually affect people who sweat
a lot during strenuous activity. 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.
Recognizing Heat Cramps
Heat cramps are muscle pains or spasms—usually
in the abdomen, arms, or legs—that may occur in association
with strenuous activity. If you have heart problems or are on
a low-sodium diet, get medical attention for heat cramps.
What to Do
If medical attention is not necessary, take these steps:
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.
Sunburn should be avoided because it damages the skin. Although
the discomfort is usually minor and healing often occurs in about
a week, a more severe sunburn may require medical attention.
Symptoms of sunburn are well known: the skin
becomes red, painful, and abnormally warm after sun exposure.
What to Do
Consult a doctor if the sunburn affects an infant
younger than 1 year of age or if these symptoms are present:
- Severe pain
Also, remember these tips when treating
- Avoid repeated sun exposure.
- Apply cold
compresses or immerse the sunburned area in cool water.
moisturizing lotion to affected areas. Do not use salve, butter,
- Do not break blisters.
Heat rash is a skin irritation caused by
excessive sweating during hot, humid weather. It can occur at any
age but is most common in young children.
Recognizing Heat Rash
Heat rash looks like a red cluster of pimples or small blisters.
It is more likely to occur on the neck and upper chest, in the
groin, under the breasts, and in elbow creases.
What to Do
best treatment for heat rash is to provide a cooler, less humid
environment. Keep the affected area dry. Dusting powder may be
used to increase comfort, but avoid using ointments or creams—they
keep the skin warm and moist and may make the condition worse.
Treating heat rash is simple and usually does not
require medical assistance. Other heat-related problems can be
much more severe.
One Last Hot Tip…
These self-help measures are not a substitute for medical care
but may help you
to recognize and respond promptly to warning signs of trouble.
Your best defense
against heat-related illness is prevention. Staying cool and making
in your fluid intake, activities, and clothing during hot weather
can help you to
remain safe and healthy.
U.S. Department of Health And Human Services
Centers for Disease Control and Prevention