Steve McLaughlin, MD
Dr. Steve McLaughlin, chair of the UNM Department of Emergency Medicine and an avid runner, says that with proper planning, it's possible to exercise safely during heat waves.
Credit: John Arnold

Even as New Mexico swelters in record-breaking heat this week, you will see them – road-side warriors jogging alongside the asphalt, cyclists peddling to and from work and tennis buffs pounding the court while the thermometer streaks up to the 100 degree mark. But is that kind of exertion safe in extreme heat?

With proper planning, it is possible to exercise safely during a heat wave, according to a UNM Hospital emergency room physician.

As a runner himself, Dr. Steve McLaughlin knows athletes won’t let the soaring temperatures stop them from exercising. But as the chair of the UNM Department of Emergency Medicine, he has also seen firsthand how dangerous it can be when people disregard the special risks that accompany exercising in heat.

"Heat does stress your body," he said. "The cardio-vascular system has to work harder to cool internal organs in the heat and people with with cardio-vascular illnesses should think twice and check with their doctor before exercising on hot days."

Potential summertime healthrisks for exercisers break down into three areas: overheating, dehydration and sunburn.

Everyone should avoid exercising outside during the hottest part of the day. Good planning will help avoid dehydration.

“It is a two-part process," McLaughlin said. "Blood is made up of water and sodium so you need to increase both if you are exercising in heat. Plan on a light snack 90 minutes before you go out, and drink one to three eight-ounce glasses of water prior to exercising. Then replenish that as you exercise.”

There is no a magic formula for how much water one needs, but the color of a person’s urine is a good marker of adequate hydration. It should be a light yellow. Something darker may signal a person is becoming dehydrated, McLaughlin said.

Finally, sunburn is a potential risk. Exercisers should stay out of the sun during the hours of peak exposure and wear a hat and sunscreen.

The negative health effects of too much heat can range from the small and nagging to the truly life threatening. Dehydration begins with thirst and leads to chills and muscle cramps. A sudden tiredness may signal heat exhaustion, a condition where the body begins to lose the ability to cool itself off. A common symptom for that is sudden tiredness.

“Typically these sorts of situations will get better,” McLaughin said. “If you are experiencing them, or if you are outside with someone who is, then the first step is to stop and get into some shade. Loosen clothing to help the body cool. Drink some water “

More serious symptoms can be a sign that someone is beginning to have a heat stroke, where the body’s core temperature begins shooting up. It can potentially be fatal.

“If you are with someone who begins to have problems standing or who is becoming confused, then dial 911 and get medical help,” said McLaughin. 

“It is simply a fact that the body has to work harder when it is hot. But, if you accept that heat makes exercise more difficult and adjust your goals and expectations then you can be safe when it is hot. Just take it easy, go slower and watch for signs of exhaustion and fatigue," he said.