This article is from the Aerobics Fitness FAQ, by firstname.lastname@example.org (Robles) with numerous contributions by others.
People at risk for heat-related illnesses include those who
work or exercise outdoors, elderly people, young children, and
people with health problems. Also at risk are those who have
had a heat-related illness in the past, those with medical
conditions that cause poor blood circulation, and those who take
medications to get rid of water (diuretics).
People usually try to get out of extreme heat before they begin
to feel ill. However, some people do not or cannot. Athletes
and those who work outdoors often keep working even after they begin
to feel ill. Those living in poorly ventilated or poorly insulated
or poorly heated buildings are at risk of heat emergencies Many
times, they might not even recognize that they are in danger of
(from Jennifer Robles (Neefer) <email@example.com.>)