U.S. Department of Health And Human Services

Centers for Disease Control and Prevention
For more information on hot weather conditions and health, please contact:

Centers for Disease Control and Prevention

National Center for Environmental Health, MS F52

4700 Buford Hwy, Atlanta, GA 30341-3717

1-888-232-6789; EHHEinq@cdc.gov

http://www.cdc.gov/nceh/hsb/extremeheat/
hen winter temperatures drop 

significantly below normal, staying

arm and safe can become a chal- w

lenge. Extremely cold temperatures

often accompany a winter storm, so you

may have to cope with power failures and

icy roads. Although staying indoors as much as possible can

help reduce the risk of car crashes and falls on the ice, you

may also face indoor hazards. Many homes will be too

cold—either due to a power failure or because the heating

system isn’t adequate for the weather. When people must

use space heaters and fireplaces to stay warm, the risk of

household fires increases, as well as the risk of carbon

monoxide poisoning. 

Exposure to cold temperatures, whether indoors or outside,

can cause other serious or life-threatening health problems.

Infants and the elderly are particularly at risk, but anyone

can be affected. To keep yourself and your family safe, you

should know how to prevent cold-related health problems

and what to do if a cold-weather health emergency arises. 

The emergency procedures outlined here

training in first are not a substitute for 

aid. However, these procedures will help

you to know when to seek medical care

and what to do until help becomes available. 

What Is Extreme Cold? 

What constitutes extreme cold and its effects can vary

across different areas of the country. In regions relatively

unaccustomed to winter weather, near freezing temperatures

are considered “extreme cold.” Whenever temperatures

drop decidedly below normal and as wind speed increases,

heat can leave your body more rapidly. These weatherrelated conditions may lead to serious health problems.

Extreme cold is a dangerous situation that can bring on

health emergencies in susceptible people, such as those

without shelter or who are stranded, or who live in a home

that is poorly insulated or without heat.

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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.

During Hot Weather

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 is hot.

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. 

2
Prepare Your Home for Winter

Although periods of extreme cold cannot always be predicted

forecasts can sometimes provide ar in advance, weather f

you with several days’ notice. Listen to weather 

forecasts regularly, and check your emergency supplies

whenever a period of extreme cold is predicted. 

If you plan to use a fireplace or wood stove for emergency

heating, have your chimney or flue inspected each year.

Ask your local fire department to recommend an inspector,

or find one in the yellow pages of your telephone directory

under “chimney cleaning.”

Also, if you’ll be using a fireplace, wood stove, or kerosene

heater, install a smoke detector and a battery-operated 

carbon monoxide detector near the area to be heated. Test

them monthly, and replace batteries twice yearly. 

our ability to feel a change in temperature decreases with Y

age, and older people are more susceptible to health 

problems caused by cold. If you are over 65 years old,

place an easy-to-read thermometer in an indoor

location where you will see it frequently, and

check the temperature of your home often

during the winter months.

Insulate any water lines that run along exterior walls so

your water supply will be less likely to freeze. To the extent

possible, weatherproof your home by adding weatherstripping, insulation, insulated doors and storm windows,

or thermal-pane windows.

If you have pets, bring them indoors. If you cannot bring

them inside, provide adequate shelter to keep them warm

and make sure that they have access to unfrozen water.

3
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.

• People 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 heat sickness. 

• 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.

4
Indoor Safety

Heat Your Home Safely

If you plan to use a wood stove, fireplace, or space heater,

be extremely careful. Follow the manufacturer’s instructions

as well as the home safety measures on page 3, and remember

these safety tips: 

Use fireplace, wood stoves, or other combustion •

heaters only if they are properly vented to the outside

and do not leak flue gas into the indoor air space.

Do not burn paper in a fireplace. •

Ensure adequate ventilation if you must use a •

erosene heater. k

Use only the type of fuel your heater is designed to •

use—don’t substitute.

that Do not place a space heater within 3 feet of anything •

may catch on fire, such as drapes, furniture, or bedding,

and never cover your space heater.

er place a space heater on top of furniture or near water. ev • N

er leave children unattended near a space heater. ev • N

Make sure that the cord of an electric space heater •

is not a tripping hazard but do not run the cord

under carpets or rugs. 

oid using extension cords to plug in your space heater. v • A

If your space heater has a damaged electrical cord or •

produces sparks, do not use it. 

Store a multipurpose, dry-chemical fire extinguisher •

near the area to be heated.

Light and Cook Safely

If there is a power failure:

Use battery-powered flashlights or •

lanterns rather than candles, if possible. 

er leave lit candles unattended. ev • N

er use a charcoal or gas grill ev • N

indoors—the fumes are deadly. 

Never use an electric generator indoors,

inside the garage, or near the air intake of your house

because of the risk of carbon monoxide poisoning: 

Plug in appliances to the generator using individual •

heavy-duty, outdoor-rated cords. 

Do not use the generator or appliances if they •

are wet because of the risk of electrocution. 

Do not store gasoline indoors where •

the fumes could ignite.

5
Hot Weather Health

Emergencies

Even 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

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 

• Throbbing headache 

• Dizziness 

• Nausea 

• Confusion 

• Unconsciousness

6
boil for one minute will kill most microorganisms or parasites 

that may be present, but won’t remove chemical pollutants

sometimes found in snow.

Eat and Drink Wisely

Eating well-balanced meals will help you

stay warmer. Do not drink alcoholic or

caffeinated beverages—they cause your

body to lose heat more rapidly. Instead,

drink warm, sweet beverages or broth to

perature. If help maintain your body tem

you have any dietary restrictions, ask

your doctor. 

Outdoor Safety 

When the weather is extremely cold, and especially if there

are high winds, try to stay indoors. Make any trips outside

as brief as possible, and remember these tips to protect your

health and safety: 

Dress Warmly and Stay Dry 

Adults and children should wear: 

hat • a

scarf or knit mask to • a

cover face and mouth 

sleeves that are snug at the wrist •

mittens (they are warmer than gloves) •

ater-resistant coat and boots • w

eral layers of loose- ev • s

itting clothing f

Be sure the outer layer of your clothing is tightly

en, preferably wind resistant, to reduce body-heat loss ov w

caused by wind. Wool, silk, or polypropylene inner layers of

clothing will hold more body heat than cotton. Stay dry—

wet clothing chills the body rapidly. Excess perspiration

will increase heat loss, so remove extra layers of clothing

whenever you feel too warm. Also, avoid getting gasoline

fueling your car skin while de-icing and or alcohol on your 

or using a snow blower. These materials in contact with the

skin greatly increase heat loss from the body. Do not ignore

shivering. It’s an important first sign that the body is losing

heat. Persistent shivering is a signal to return indoors. 

7
Recognizing Heat Exhaustion

Warning signs of heat exhaustion include the following:

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 

• Rest 

• Cool shower, bath,

or sponge bath 

• An air-conditioned

environment 

• Lightweight

clothing

Heat Cramps 

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.

• Heavy sweating 

• Paleness 

• Muscle cramps 

• Tiredness 

• Weakness 

• Dizziness 

• Headache 

• Nausea or vomiting 

• Fainting 

8
void Ice A

alking on ice is extremely dangerous. Many cold-weather W

injuries result from falls on ice-covered sidewalks, steps,

driveways, and porches. Keep your steps and walkways as

free of ice as possible by using rock salt or another chemical

de-icing compound. Sand may also be used on walkways to

reduce the risk of slipping.

Be Safe During Recreation

Notify friends and family where you will be before you go

hiking, camping, or skiing. Do not leave areas of the skin

xposed to the cold. Avoid perspiring or becoming over- e

tired. Be prepared to take emergency shelter. Pack dry

clothing, a two-wave radio, waterproof matches and paraffin

ire starters with you. Do not use alcohol and other mood f

altering substances, and avoid caffeinated beverages.

oid walking on ice or getting wet. Carefully watch for Av

signs of cold-weather health problems.

Be Cautious About Travel

Listen for radio or television reports of travel •

advisories issued by the National Weather Service. 

Do not travel in low visibility conditions. •

oid traveling on ice-covered roads, v • A

erpasses, and bridges if at all possible. ov

If you must travel by car, use tire chains •

and take a mobile phone with you. 

If you must travel, let someone know •

your destination and when you

xpect to arrive. Ask them to notify e

authorities if you are late. 

Check and restock the winter emergency •

supplies in your car before you leave. 

er pour water on your windshield ev • N

to remove ice or snow; shattering may occur. 

Don’t rely on a car to provide sufficient •

heat; the car may break down. 

ays carry additional warm clothing lw • A

appropriate for the winter conditions.

9
Heat Rash

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

The 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. 

10
ictims of hypothermia are often (1) elderly people with V

inadequate food, clothing, or heating; (2) babies sleeping in

cold bedrooms; (3) people who remain outdoors for long

periods—the homeless, hikers, hunters, etc.; and (4) people

who drink alcohol or use illicit drugs.

Recognizing Hypothermia

arnings signs of hypothermia: W

What to Do

If you notice any of these signs, take the

person’s temperature. If it is below 95°,

the situation is an emergency—get

medical attention immediately. 

If medical care is not available, begin warming the

person, as follows:

Get the victim into a warm room or shelter. •

If the victim has on any wet clothing, remove it. •

arm the center of the body first—chest, neck, head, • W

and groin—using an electric blanket, if available. Or

use skin-to-skin contact under loose, dry layers of

blankets, clothing, towels, or sheets. 

arm beverages can help increase the body temperature, • W

ut do not give alcoholic beverages. Do not try to give b

beverages to an unconscious person. 

After body temperature has increased, keep •

the person dry and wrapped in a warm 

blanket, including the head and neck. 

Get medical attention as soon as possible. •

A person with severe hypothermia may be unconscious and

may not seem to have a pulse or to be breathing. In this

case, handle the victim gently, and get emergency assistance

immediately. Even if the victim appears dead, CPR should

be provided. CPR should continue while the victim is being

armed, until the victim responds or medical aid becomes w

ailable. In some cases, hypothermia victims who appear av

to be dead can be successfully resuscitated.

Adults: 

shivering, exhaustion •

confusion, fumbling hands •

memory loss, slurred speech •

drowsiness •

Infants: 

bright red, cold skin •

ery low energy • v

11