A prolonged heat wave can be tough on anyone, but if you
have heart disease you need to be especially careful when it's hot. This is
because the high environmental temperatures can put excess stress on your heart,
and also because it is often easier for people with heart disease to develop
potentially dangerous heat illness.
In a hot environment, the body attempts to dissipate excess heat (mainly by
sweating, and by radiating heat from the skin) to maintain a reasonably normal
body temperature. The need to dissipate heat places added stress on your
cardiovascular system, and this stress may cause the symptoms of your underlying
heart disease to worsen. For instance, a person with coronary artery disease may
develop angina; or a person with heart failure may have more shortness of
In extreme heat, the body's attempts to dissipate heat can become overwhelmed,
and if this happens the body's temperature begins to rise. The increase in body
temperature, along with the dehydration and electrolyte imbalances that most
often accompany it, produces heat illness.
Heat illness is a continuum of disorders ranging from heat rash, to heat cramps
(muscle cramps), to heat exhaustion (cramps, weakness, dizziness, nausea and
vomiting, headache), to heat stroke (body temperature of 106 degrees F. or
higher, plus neurological symptoms such as seizures, disorientation, or coma).
Heat stroke can be fatal.
Unfortunately, the drugs that are often used in treating heart disease can make
it more difficult for your body to dissipate excess heat when temperatures are
very high, and thus, may make heat illness more likely. Almost any
cardiovascular medication can make you more prone to heat illness, but this is
especially true with beta blockers, calcium channel blockers, and diuretics.
So, while everyone should take precautions during a heat wave, it is especially
important to do so if you have heart disease. The most important thing to do is
to stay in a cool environment during the heat of the day. If you don't have air
conditioning, consider going to the mall, to a church, or to a neighbor's. Avoid
exertion, since the calories you burn during exercise will just produce that
much more heat that your body will need to dissipate. And stay very well
hydrated on hot days, preferably by drinking water (and avoiding caffeine, which
is a diuretic).
If you should develop signs of heat illness, such as muscle cramps or nausea,
call your doctor immediately.
And DO NOT stop any of your cardiac medications on your own, without checking
with your doctor first.