Hot Summer Days Can Make Sick People Sicker

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Hot Summer Days Can Make Sick People Sicker

Extreme heat can affect anyone, but you don't have to become a

victim.

By R.

WebMD Feature Reviewed by Louise Chang, MD

http://www.webmd.com/heart-disease/features/hot-summer-days-can-make-

sick-people-sicker

Most people know that extreme heat can make us sick. But we may

think of heat-related illness as something that only affects people

who are overdoing it -- like overheated marathon runners,

professional athletes, or new recruits doing drills on military

bases.

But most people who die from heat stroke in the U.S. -- about 400

every year, and possibly more -- don't get it from overexerting

themselves on a muggy day. In certain people during high

temperatures, it's all too easy to develop heat stroke while sitting

perfectly still on the couch.

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.

" People just don't understand the risks of extreme heat, " says

McGeehin, PhD, MSPH, director of the division of

Environmental Hazards and Health Effects, at the CDC's National

Center for Environmental Health. " They aren't aware how quickly they

can get into trouble. "

And while heat-related illness can be a problem for anybody, the

risks aren't equal. People who have certain medical conditions or

who take some medications to treat those conditions are at a greater

risk of having problems in hot weather.

" Any chronic disease lowers your threshold to heat injury, " says

Knochel, MD, from the Presbyterian Hospital of

Dallas. " There's no question that people with medical conditions are

at higher risk, although they may not know it. "

" If you go to the ER of a hospital and look at the people who are

there for heat stroke, " Knochel tells WebMD, " most of them are going

to be older and have cardiovascular disease, or diabetes, or another

chronic condition. "

But these illnesses and deaths can be prevented. If you are at risk,

then you can learn how to protect yourself. Heat and Disease

In order to work well, the body has to stay at a normal temperature.

If it heats up even by a few degrees, your body starts to cool

itself. The most obvious and familiar reaction is that you start to

sweat. As the hot perspiration evaporates off your skin, you're

cooled down.

The body reacts to heat in many other, less obvious ways. For

instance, hot temperatures make your heart beat faster. That's not

only if you're exercising. Even if you're sitting perfectly still,

your heart will be beating harder when you're hot. That's because

the heart is working harder to push blood to the skin and muscles.

Getting blood closer to the surface of the body gets it to cool down

and helps with sweating.

While this system works pretty well in a healthy person, it may not

work so well in people with chronic illnesses.

" Anything that interferes with our natural cooling system could lead

us to heat exhaustion and heat stroke faster, " McGeehin tells

WebMD. " A lot of medical conditions can do that. "

When the body can't get rid of excess heat fast enough, the cooling

system eventually breaks down, and the organs begin to overheat. If

they get hot enough, they'll stop working. Confusion, seizures,

permanent disability, and even death can occur if treatment isn't

provided. That's heat stroke and it's a medical emergency.

Medical Conditions and Heat Stroke - A number of common health

conditions raise the risk of heat stroke including:

Heart disease. One of body's responses to heat is to make the heart

beat faster. But in many people with heart disease, the damaged

heart may not be able to pick up the pace. If the heart can't beat

quickly enough, your body won't be able to cool off as well.

People with heart conditions sometimes take medications called

diuretics commonly known as water pills -- which reduce the amount

of fluid in the body. When people take water pills, they may become

dehydrated easily. The typical advice for people in hot weather " to

drink lots of fluids " may not be all that safe for people with heart

failure, whose hearts have difficulty handling excess fluid. This

can result in backup of fluid in the lungs which can impair

breathing.

Other drugs that are sometimes used for heart problems, such as beta-

blockers, can also cause problems. Beta-blockers (such as Toprol,

Tenormin, and Lopressor) can prevent the heart from beating as

quickly as it needs to during hot weather. This can prevent the

body's natural cooling system from lowering the body temperature.

High blood pressure. " Hypertension affects the body's ability to

keep itself cool, " says McGeehin. " It also places greater stress on

the heart. " In addition, many people with hypertension are on low-

salt diets. Not having enough salt in the system can lower the

threshold to heat stroke.

Diabetes. People with diabetes can be dehydrated when their blood

sugars are not under control, says Knochel, and dehydration can

prevent the body from sweating normally. Unfortunately, many people

with diabetes may not even be aware that they're dehydrated and

don't take extra precautions.

Obesity. Doctors have come to recognize that obesity is a serious

health problem in America. It poses a number of risks, including an

increased danger of having a heat-related illness. Part of the

problem is simple physics. The bigger the person, the harder it is

to lose excess heat. The body's natural cooling systems can't work

quickly enough. Obesity also puts extra pressure on the heart, so

when hot weather requires that the heart beats even harder, it may

not be up to the task, Knochel says.

Signs of Heat-Related Illness

It's important to know the signs of trouble. Excessive heat can

first cause heat exhaustion -- especially in people who are working

or exercising outside. The symptoms include:

Dizziness or fainting

Heavy sweating

Muscle cramps

Cold or clammy skin

Headaches

Rapid heartbeat

Nausea

If you have these symptoms, get out of the heat, drink water, juice

or sports drinks (unless your doctor tells you otherwise), and get

medical attention.

If it isn't treated, heat exhaustion can lead to heat stroke, which

is an emergency. Heat stroke also develops in people who aren't

being physically active but are simply in a hot environment. The

signs of heat stroke are

Rapid heartbeat

Confusion or delirium

Warm, dry skin (because the body is no longer able to sweat)

Fever of greater than 104 degrees

Severe headaches

Seizure or muscle twitching

Unconsciousness

Death

Remember, heat stroke needs immediate attention. Call 911. Other

Dangers

Heat exhaustion and heat stroke aren't the only risks for people

with pre-existing medical conditions. For entirely different

reasons, some other conditions are exacerbated by the hot weather of

the summer. Some examples are:

Asthma. Heat doesn't make asthma worse, at least not directly. But

people with asthma need to be especially careful in summer months,

since the air can be filled with all sorts of triggers. Allergens

like molds and pollens drift in the wind. Irritants, such as

environmental pollution, can hang in the air on hot, humid days and

make life miserable for people with asthma. These environmental

pollutants can cause plants and molds to boost pollen and spore

production. The more pollen in the air the more likely it is to

worsen allergic diseases such as asthma. In addition, some

medications used to treat asthma may make it harder to sweat, and

thus interfere with the body's natural cooling process.

Multiple Sclerosis. Many people with MS find their symptoms are

aggravated by heat. In fact, one of the oldest tests for MS was to

put a person suspected of having the disease in a hot bath. If

neurological symptoms developed, the doctor made his diagnosis.

Anyone with MS should take extra precautions to stay cool.

Lupus. About 70% of people with lupus find that exposure to sunlight

can cause a flare-up of symptoms, including skin rashes, fatigue,

and joint pain. So make sure to cover yourself with long pants and

sleeves, wear a hat, and use sunscreen.

Medication and Heat Stroke Risk

It's not just the medical conditions themselves that can raise the

risk of heat-related illness. In many people, it's the medicine that

is the problem. We've already seen that some of the medicines used

to treat conditions, such as heart failure, can cause trouble.

However, medicines for entirely different conditions can aggravate

the effects of heat. For instance, a person with an anxiety disorder

might never suspect that he or she was at a higher risk of heat

stroke. But if he or she is taking a tranquilizer to treat the

condition, the body may not be able to cool itself efficiently.

Drugs that can increase the risk of heat-related illness include:

Some psychotropic medicines, such as Haldol and Thorazine

Anticholinergics, such as Cystospaz

Beta-blockers, such as Toprol, Tenormin, or Inderal

Diuretics, such as Lasix or Maxzide

Not only prescription drugs cause problems -- herbs and other

alternative medicines can be risky too.

Alcohol and street drugs also increase the dangers. For one thing,

alcohol dehydrates you and can interfere with the body's cooling

process. Alcohol and drugs also hinder people's ability to reason

clearly, making them more likely to stay in the heat longer than

they should.

There are many other factors too. People with low incomes living in

cities are usually the hardest hit by heat waves. Older people are

especially at risk, partially because they simply can't sense

temperature as accurately as they used to, Knochel says.

Many of these risk factors -- medical, social, and economic -- can

merge together. For instance, imagine an older woman who lives in a

city on a fixed income, doesn't have air-conditioning (or is too

worried about the costs to turn it on), and takes medications for

heart disease and high blood pressure. She is at a much higher risk

of developing heat stroke than the average person. But she -- and

her family -- may have no idea.

Enjoying the Summer Safely

Although excess heat can certainly cause problems, we're not trying

to dissuade people from getting outside and enjoying themselves

during the summer. Getting outside and getting some physical

activity is good for just about everybody -- with medical conditions

or not.

But if you're at higher risk of having problems from the heat

because of a medical condition, just take some extra precautions.

Remember, you need to get out of the heat sooner than the people

around you.

On the whole, someone with a medical condition should follow the

same precautions as anyone else on a hot day. To prevent heat-

related illnesses:

Don't go outside during the hottest times of the day.

Spend time in a cool place. If you don't have air conditioning, go

somewhere that does, such as a friend's home, a mall, or a library.

Drink extra water (unless your doctor tells you otherwise), and

avoid alcohol and drinks with caffeine.

Wear loose-fitting cotton clothes.

Pay attention to weather reports and try to plan ahead for hot days.

Also, remember to check on older relatives or friends who might be

at higher risk of heat-related illness because of medical

conditions. Make sure that they're staying cool on hot days.

The fact is, as Knochel says, ANY KIND of chronic health condition

can lower the threshold for developing heat-related illness. He

suggests talking to your health care provider to find out if you're

at higher risk and how to protect yourself. You may just need to

take a few extra precautions to have a healthy and happy summer.