the heat is on! managing heat related illness

Patricia Carroll, RN,BC, CEN, RRT, MS

As I sit here writing this, we in New England are on our eighth day of temperatures above ninety degrees. And when it gets hot here, the humidity is usually high to match. Heat-related illnesses can range from uncomfortable to dangerous at this time of year. In June, an article I wrote about heat-related illnesses for my colleagues in home care nursing was published in the journal Home Healthcare Nurse. Here’s the quick-read version for you.

Take heat-related illnesses seriously. If you’re in the middle of a heat wave, pay attention to the signs and symptoms listed below. Check on older relatives and neighbors to make sure they’re coping with the heat properly.

• Heat rash and prickly heat are itchy, raised, red rashes that appear when sweat glands become plugged. The best prevention is to wear (or dress other family members in) clean, lightweight, loose fitting absorbent clothing – I like cotton best. If the rash becomes crusty, or is surrounded by red skin or red streaks going up the arm or leg, the rash may be infected, and a check with your healthcare provider is in order.

• Heat edema is swelling in the legs caused when blood vessels dilate in the heat. It is not a serious condition, and it most commonly occurs in people who have damaged blood vessels from high blood pressure or diabetes, or in those not accustomed to the heat. Treat the swelling by elevating the legs, move to a cooler environment, and gradually get used to the heat.

• Heat cramps are painful spasms of muscles in the arms and legs that occur when a person has been working hard in a warm to hot environment. These cramps can be seen in athletes (particularly summer football practice with full pads), firefighters in turnout gear, and people exposed to heat such as during asphalt paving. The spasms usually occur when activity stops. Replace fluids and move to a cooler area -- at least, in the shade; at best, in air conditioning.

• Heat syncope (sin-coe-pea) is the medical term used when someone gets woozy or actually passes out after a long period of standing, or getting up too quickly from a sitting or lying position in a hot environment. This is not a serious condition, and people recover as soon as they are lying down. In seniors, the greatest concern is that they could injure themselves if they pass out and fall down. If this happens to someone near you, get him or her to a cooler environment and offer fluids. Some people get lightheaded or sick to their stomachs before they pass out – this is a warning to get out of the heat and take it easy for a little while.

• Heat exhaustion is more serious than the heat-related illnesses already mentioned, and it is more common than the others. Heat exhaustion occurs when you get dehydrated by losing water through sweat. If you’re in a low humidity environment such as a sauna or in the Southwestern US, you may not realize how much water you’re losing because the perspiration evaporates so quickly off the skin into the dry air. If humidity is high, sweat may not evaporate at all and the body’s natural cooling mechanism will not work efficiently. If you have heat exhaustion, you usually feel crummy. There isn’t one thing that makes us say, "Ah ha! Heat exhaustion!" Rather, it is a number of signs and symptoms including weakness, exhaustion, dizziness, nausea, and sometimes vomiting. You’ll remain alert, you’ll just feel bad. Heat exhaustion is worth, at minimum, a call to your healthcare provider. If you have any chronic illnesses, or a very young or very old family member is affected, a visit to the emergency department is in order.

• Heat stroke is the most dangerous heat-related illness – people die from heat stroke. In recent years, there has been an increase in the number of young athletes, particularly football players, who have died from heat stroke. There are two key differences between heat exhaustion and heat stroke – in heat stroke, the body temperature is 104.9 or above, and the patient is unconscious, wildly confused and delirious, or comatose. These people have completely lost the ability to regulate their own body temperature, so we have to cool them down. People once thought that people with heat stroke didn’t sweat, but that’s not necessarily true. If a person is sweating and their mental status is not what’s normal for them, call emergency medical services and start cooling measures immediately.

If you’re with someone you think is suffering from heat stroke, the most important thing you can do while waiting for the emergency medical service professionals to arrive is to start trying to cool the person. Here’s what to do:

• Remove as much clothing as possible, particularly uniforms
• Cover the person with sheets or towels wet with cool water
• Blow a fan across the person after the wet sheets/towels are in place
• Place cool, damp cloths on the head and face
• Make ice packs and put them in the armpits, the crease in the groin at the hip, and the back of the neck

You can also use some of these measures to help cool anyone who has a heat-related illness.

Certain types of medications that can increase the risk of heat-related illness; check with your pharmacist or health care provider. Also ask about physical conditions that can increase risk. 

Environmental factors also make a big difference. People will be at greater risk if they:

• Have no air conditioning
• Have no trees or shrubbery around the building in which they live or work
• Are suddenly exposed to hot temperature
• Live in the upper floors of a tall, non-air-conditioned building
• Live in a city surrounded by asphalt, concrete, bricks, and other building materials that hold heat and limit how low the temperatures can get at night to cool things off

In addition, children and seniors are at greater risk because their bodies don’t adapt to heat as well as other people, they may not be sensitive to thirst, and they may not be mobile enough to get a drink when they want one.

You’ve probably heard it a hundred times – "It’s not the heat, it’s the humidity." That time-honored phrase is true. In fact, because of heat waves in summers past, the National Weather Service (NWS) has published a Heat Index Chart that allows you to determine heat index (also called the apparent temperature) from the air temperature and the relative humidity – this is the heat stress your body is subjected to. To see this chart, click here. The NWS now issues heat alerts, just like thunderstorm watches and warnings, to alert the public to potentially dangerous conditions. Your local weather report on the Web may call this temperature the "real feel." Whatever it’s called, this is the number to watch when you’re in a heat wave.

If you don’t have air conditioning, or you know an elderly relative or neighbor who doesn’t have it, think about ways to get into a cool environment for part of the day. Go to the movies, a shopping mall, the supermarket, or a public library. Many senior centers open their doors for members of the community during heat waves, and some cities and towns set up cooling centers, particularly if there is a power outage at the same time.

A heat wave is no time to lose your cool – using your head can keep you more comfortable and safe during times of heat stress.

Written: August 2002

Reviewed: June 2003, May 2004