This is SCIENCE IN THE NEWS in VOA Special English. I’m Bob Doughty.
And I’m Faith Lapidus. This week, we tell about some health problems linked
to extreme heat. We also tell about what to do to prevent and treat these
Extremely hot weather is common in many parts of the world. Although hot
weather just makes most people hot, it can cause medical problems -- and death.
Floods, storms and other natural events kill thousands of people every year.
And, as expected, we hear much about them in news reports. We generally hear
little, however, about what experts say may be nature’s deadliest killer --
Health experts say that between nineteen seventy-nine and nineteen
ninety-nine, extremely hot weather killed more than eight thousand people in the
United States. In that period, more Americans died from extreme heat than from
severe storms, lightning, floods and earthquakes together. And in nineteen
ninety-five, more than six hundred people died in a period of extremely hot
weather in one city -- Chicago, Illinois.
To measure extreme heat, weather experts have developed the Mean Heat Index.
It measures the average of how it felt all day on an extremely hot day.
Experts say it is the total heat of a hot day or several hot days that can
affect health. Several hot days are considered a heat wave. Experts say heat
waves often become deadly when the nighttime temperature does not drop much from
the highest daytime temperature. This causes intense stress on the human body.
Doctors say people can do many things to protect themselves from the dangers
of extreme heat. Stay out of the sun, if possible. Drink lots of cool water.
Wear light-colored clothing made of natural materials. Make sure the clothing is
loose, permitting freedom of movement. And learn the danger signs of the medical
problems that are linked to heat.
The most common medical problem caused by hot weather is
heat stress .
Usually, it also is the least severe. The causes of heat stress include physical
work or exercise, heavy clothes, hot weather or high humidity. Humidity is the
amount of water in the air.
Several of these conditions together can raise a person’s body temperature
above safe limits. The person perspires heavily, losing large amounts of body
water and salt.
For most people, the only result of heat stress is muscle pain. The pain is a
warning that the body is becoming too hot. Doctors say drinking water will help
the pain disappear after the body again has the right amounts of water and salt.
For some people, however, the result is more serious. For people who are not in
good health, heat can make an existing medical problem worse.
For example, doctors say some people face a greatly increased danger from
heat stress. These people have a weak or damaged heart, high blood pressure, or
other problems of the blood system. Severe heat can help cause a heart attack or
stroke. Health experts say this is the most common cause of death linked to hot
Doctors also say severe heat increases problems for small children, older
people and people suffering from the disease diabetes. It also is bad for people
who weigh too much and have too much body fat, and for people who drink alcohol.
Hot weather also increases dangers for people who must take medicine for high
blood pressure, poor blood flow, nervousness or depression.
If heat stress is not treated, it can lead to a more serious problem called
heat exhaustion. Perspiration is one of the body’s defenses against heat. That
is how the body releases water to cool the skin. However, a person suffering
from heat exhaustion loses too much water through perspiration. The person
Dehydration limits a person’s ability to work and think. Experts say a
reduction of only four or five percent in body water leads to a drop of twenty
to thirty percent in work ability. The loss of salt through perspiration also
reduces the amount of work that muscles can do.
A person suffering from heat exhaustion feels weak and extremely tired. He or
she may have trouble walking normally. Heat exhaustion also may produce a
general feeling of sickness, a fast heartbeat, breathing problems, and pain in
the head, chest or stomach. Doctors say people suffering from these problems
should move to a cool place and drink water.
Heat exhaustion can develop quickly. But it also can develop slowly, over
several days. Doctors call this disorder dehydration exhaustion. Each day, a
person’s body loses only a little more water than is taken in. The person may
not even know the problem is developing. But if the problem continues for
several days, the effects will be the same as the usual kind of heat exhaustion.
The treatment for dehydration exhaustion is the same as for heat exhaustion.
Drink large amounts of water, and rest in a cool place.
Heat exhaustion can lead to heat
stroke if it is not treated. With heat
stroke, the body temperature rises to more than forty degrees Celsius.
The body stops perspiring. And the skin becomes dry and very hot. A person
may even become unconscious, not knowing what is happening.
Doctors say the body’s tissues and organs begin to cook when body temperature
is higher than forty-two degrees Celsius. Permanent brain damage and death may
result. Immediate medical help is necessary for someone with heat stroke.
Doctors say immediate treatment is necessary or the person could die before help
Immediate treatment should begin by moving the victim out of the sun. Raise
the person’s feet up about thirty centimeters. Then, take off the person’s
clothing. Put water on the body. And place pieces of ice in areas where blood
passageways are close to the skin. These areas include the back of the neck and
under the arms. The purpose is to cool the victim as quickly as possible to stop
the body’s temperature from increasing.
Experts say it is important to know the danger signs of each of the medical
disorders linked to hot weather. And they say you should know what to do if the
Experts say water is important for many health reasons.
The body itself is mostly water -- more than sixty-five percent water. Water in
blood carries hormones and antibodies
through the body. Water in urine carries away waste
materials. Water is also needed for cooling the body on hot days, and when we
are working or exercising. Water carries body heat to the surface of the skin.
There, the heat is lost through perspiration.
Health experts say adults should drink about two liters of water each day to
replace all the body water lost in liquid wastes and perspiration. They say
people should drink more than that in hot weather.
Experts say it is especially important to drink before, during and after
exercise. They say we should drink water even before we start to feel like we
need something to drink. This is because we sometimes do not feel thirsty until
we already have lost a lot of body liquid.
In hot weather, drinking cold liquids is best. They do more than just replace
lost body water. Cold liquids also help cool us faster than warm liquids. This
is because they take up more heat inside the body and carry it away faster.
Yet experts say that sweet drinks are not good to drink in hot weather. The
sugar slows the liquid from getting into the blood system. Tea and coffee also
are not effective. Doctors also warn against alcoholic drinks. Alcohol speeds
the loss of body water through liquid wastes.
In addition to drinking cool water, doctors say there are other things that
can protect against the health dangers of heat. Stay out of the sun, if
possible. Wear loose, lightweight and light-colored clothes. Wear a hat or other
head cover while in the sun. Eat fewer hot and heavy foods. If possible, cook
foods during cooler times of the day. Also, rest more often. Physical activity
produces body heat.
Experts say these simple steps can prevent the dangerous health problems
linked to heat. They will prevent sickness, help you feel better and may even
save your life.
This SCIENCE IN THE NEWS program was written by Oliver Chanler and Nancy
Steinbach. It was produced by Brianna Blake. I’m Faith Lapidus.
And I’m Bob Doughty. Join us again next week for more news about science, in
Special English, on the Voice of America.