Ask the doctors: Recognizing and addressing heat-related dangers

Dear Doctors: My landscaping business keeps me outside a lot, and my son has a job as a line cook. Last summer that made our jobs dangerous. Can you please write about how to know if you’re in trouble with the heat and what you can do about it?

Dear Reader: You and your son are among an estimated 50 million workers in the U.S. whose occupations put them at physical risk during periods of extreme heat. This is a problem for people with outdoor jobs. However, extreme heat is also a threat in enclosed workplaces, such as warehouses, factories or commercial kitchens. Heat-related visits to hospital emergency departments reached an all-time high last year. Unfortunately, so did heat-related deaths. And with heat waves already baking large swathes of the U.S., your question is timely and important.

The trillions of life-sustaining chemical processes that take place throughout our bodies require a stable core temperature. It’s a fairly narrow range – between 97 and 99 degrees Fahrenheit. When core temperature exceeds that range, whether due to exertion, external temperature or illness, the body begins to compensate. The first steps are skin flushing and sweating. Flushing is when blood is sent to the surface of the skin to be cooled in the networks of capillaries. Sweating provides the layer of moisture needed for the cooling effect of evaporation.

During periods of high temperature, particularly when accompanied by physical activity, which causes the muscles to generate heat, flushing quickly becomes ineffective. And when humidity is also present, evaporation slows or even ceases. This sets the stage for a rise in core body temperature and the onset of a new set of heat-related symptoms. These often begin with heat cramps and dizziness. Because they can be predictors of heat exhaustion and heat stroke, they must not be ignored.

In heat exhaustion, the person sweats heavily, has clammy skin and decreased urine output, often runs a temperature, develops a weak and rapid heartbeat and may feel nauseated or vomit. If left untreated, heat exhaustion can swiftly escalate to heat stroke. Body temperature rises to 104 degrees Fahrenheit or higher, skin becomes dry and hot to the touch, the heart pounds, and seizures, mental confusion or loss of consciousness are possible. Heat stroke is always an emergency. In order to prevent brain damage, organ damage and death, immediate medical care is needed.

Heat-related illness is often a rapid and worsening cascade. That makes it crucial to address the very earliest symptoms, no matter how seemingly mild. Stop all activity and move to a cool, shaded place. Shed restrictive clothing, sip a cool beverage and cool the scalp and the skin with water. If a fan or air conditioning is available, use it. Alternate work with cooling strategies for as long and as often as needed. If symptoms of heat illness don’t abate within 30 minutes or so, or if they worsen, seek immediate medical care.

Send your questions to askthedoctors@mednet.ucla.edu.