Wave Safety Tips
down. Strenuous activities should be
reduced, eliminated, or rescheduled to the
coolest time of the day. Individuals at
risk should stay in the coolest available place,
not necessarily indoors.
for summer. Lightweight, light-colored
clothing reflects heat and sunlight, and helps
your body maintain normal temperatures.
less fuel on your inner fires. Foods (like
proteins) that increase metabolic heat
production also increase water loss.
plenty of water or other nonalcoholic fluids.
Your body needs water to keep cool. Drink plenty
of fluids even if you don't feel thirsty.
Persons who (1) have epilepsy or heart, kidney,
or liver disease, (2) are on fluid restrictive
diets, or (3) have a problem with fluid
retention should consult a physician before
increasing their consumption of fluids.
not drink alcoholic beverages.
not take salt tablets unless specified by a
physician. Persons on salt restrictive
diets should consult a physician before
increasing their salt intake.
more time in air-conditioned places. Air
conditioning in homes and other buildings
markedly reduces danger from the heat. If you
cannot afford an air conditioner, spending some
time each day (during hot weather) in an air
conditioned environment affords some protection.
get too much sun. Sunburn makes the
job of heat dissipation that much more
persons, small children, chronic invalids, those on
certain medications or drugs (especially tranquilizers and
anticholinergics), and persons with weight and alcohol
problems are particularly susceptible to heat reactions,
especially during heat waves in areas where moderate
climate usually prevails.
Related information about Heat Waves from the Federal Emergency Management Agency
Related information about Heat Waves from the American Red Cross
kills by taxing the human body beyond its abilities.
In a normal year, about 175 Americans succumb to the
demands of summer heat. Among the large continental
family of natural hazards, only the cold of winter --
not lightning, hurricanes, tornadoes, floods, or
earthquakes -- takes a greater toll. In the 40-year
period from 1936 through 1975, nearly 20,000 people
were killed in the United States by the effects of
heat and solar radiation. In the disastrous heat wave
of 1980, more than 1,250 people died.
those are the direct causalities. No one can know how
many more deaths are advanced by heat wave weather --
how many diseased or aging hearts surrender, that
under better conditions would have continued
American summers are hot; most summers see heat waves
in one section or another of the United States. East
of the Rockies, they tend to combine both high
temperatures and high humidity although some of the
worst have been catastrophically dry.
on the latest research findings, the NWS has devised
the "Heat Index" (HI), (sometimes referred
to as the "apparent temperature"). The HI,
given in degrees Fahrenheit, is an accurate measure of
how hot it really feels when the relative humidity (RH)
is added to the actual air temperature.
find the Heat Index, look at the Heat Index Chart.
As an example, if the air temperature is 95°F (found
on the left side of the table), and the relative
humidity is 55% (found at the top of the table), the
HI -- or how hot it really feels -- is 110°F.
This is at the intersection of the 95° row and the
Since HI values were devised for shady, light wind
conditions, exposure to full sunshine can increase
HI values by up to 15°F. Also, strong winds,
particularly with very hot, dry air, can be extremely
"Heat Index/Heat Disorders" table relates
ranges of HI with specific disorders, particularly for
people in the higher risk groups.
These Heat Disorder Symptoms
and pain. In severe cases, swelling of skin,
blisters, fever, headaches.
for mild cases if blisters appear. If
breaking occurs, apply dry sterile dressing.
Serious, extensive cases should be seen by a
spasms usually in muscles of legs and abdomen
possible. Heavy sweating.
pressure on cramping muscles, or gentle
massage to relieve spasm. Give sips of water.
If nausea occurs, discontinue use.
sweating, weakness, skin cold, pale and
clammy. Pulse thready. Normal temperature
possible. Fainting and vomiting.
victim out of sun. Lay down and loosen
clothing. Apply cool wet cloths. Fan or move
victim to air conditioned room. Sips of
water. If nausea occurs, discontinue
use. If vomiting continues, seek immediate
body temperature (106°F, or higher).
Hot dry skin. Rapid and strong pulse.
stroke is a severe medical emergency.
Summon medical assistance or get the victim to
a hospital immediately. Delay can be
the victim to a cooler environment.
Reduce body temperature with cold bath or
sponging. Use extreme caution.
Remove clothing, use fans and air
conditioners. If temperature rises
again, repeat process. Do not give
updated: Thursday, April 07, 2005 05:55 PM
Heat Affects the Body
bodies dissipate heat by varying the rate and depth of
blood circulation, by losing water through the skin and
sweat glands, and -- as the last extremity is reached --
by panting, when blood is heated above 98.6 degrees.
The heart begins to pump more blood, blood vessels dilate
to accommodate the increased flow, and the bundles of tiny
capillaries threading through the upper layers of skin are
put into operation. The body's blood is circulated closer
to the skin's surface, and excess heat drains off into the
cooler atmosphere. At the same time, water diffuses
through the skin as perspiration. The skin handles
about 90 percent of the body's heat dissipating function.
by itself, does nothing to cool the body, unless the water
is removed by evaporation -- and high relative humidity
retards evaporation. The evaporation process itself works
this way: the heat energy required to evaporate the sweat
is extracted from the body, thereby cooling it. Under
conditions of high temperature (above 90 degrees) and high
relative humidity, the body is doing everything it can to
maintain 98.6 degrees inside. The heart is pumping a
torrent of blood through dilated circulatory vessels; the
sweat glands are pouring liquid -- including essential
dissolved chemicals, like sodium and chloride -- onto the
surface of the skin.
disorders generally have to do with a
reduction or collapse of the body's
ability to shed heat by circulatory
changes and sweating, or a chemical (salt)
imbalance caused by too much sweating.
When heat gain exceeds the level the body
can remove, or when the body cannot
compensate for fluids and salt lost
through perspiration, the temperature of
the body's inner core begins to rise and
heat-related illness may develop.
in severity, heat disorders share one
common feature: the individual has
overexposed or over-exercised for his/her
age and physical condition in the existing
with its ultraviolet radiation burns, can
significantly retard the skin's ability to
shed excess heat.
indicate that, other things being equal,
the severity of heat disorders tend to
increase with age -- heat cramps in a
17-year-old may be heat exhaustion in
someone 40, and heat stroke in a person
has to do with adjusting sweat-salt
concentration, among other things.
The idea is to lose enough water to
regulate body temperature, with the least
possible chemical disturbance.