Tips for safe summer exercise in the heat

As Kirtland sees higher temperatures, those exercising outdoors in the warmer weather should take precautions to stay safe. (Photo by Jamie Burnett)

As Kirtland sees higher temperatures, those exercising outdoors in the warmer weather should take precautions to stay safe. (Photo by Jamie Burnett)

KIRTLAND AIR FORCE BASE, N.M. --

As summer approaches, we're enticed by the longer days and warmer weather to spend more time outdoors.

Certainly, there are a wide variety of activities from which to choose: walking, running, swimming, tennis, hiking and many others. As with any change of seasons, it's important to prepare for what's ahead.

Here are some useful tips to make your summer activities safe and enjoyable.

First, let's talk about sweat. If you're outdoors and it's hot, sweating is cool, literally.

Sweating is the primary mechanism our bodies use to keep cool. Interestingly, it's not the sweat production that cools us off -- it's the evaporation of the sweat, which pulls heat away from us.

That's why it is easier to stay cool in a hot, low-humidity environment like New Mexico, because the sweat rapidly evaporates. It's much more difficult to keep cool in a hot, humid climate, like Florida, because sweat does not evaporate as readily.

Altitude also affects sweat; at high altitudes, such as Albuquerque, the volume of sweat declines compared to sea level, but the electrolyte concentration (sodium, potassium, calcium) contained in sweat increases compared to sea level.

If you want to find out how humid the air is before you exercise, many weather websites will have this information. Pay attention to dew point, rather than relative humidity, as this is a much better indicator of how humid the air is.

A dew point of less than 60 degrees is good for exercising outdoors. A dew point between 60 and 70 degrees is moderately humid.

At a dew point of greater than 70 degrees, it's very humid, and you should take special precautions before exercising in such conditions, such as working out very early in the morning. On days like this, it might be a good idea to exercise indoors.

When exercising in hot, humid conditions, it's important to recognize symptoms of heat exhaustion, as this condition may be very dangerous. Symptoms of heat exhaustion include nausea, fatigue, dizziness and muscle cramps.

It usually takes two to three weeks for your body to adapt to hot, humid weather. These adaptations include increased blood volume, sweating more profusely and starting to sweat at a lower exercise intensity than would be the case in low-humidity conditions.

A risk factor for heat exhaustion is dehydration. How do you tell if you're dehydrated?

Your thirst reflex doesn't kick in until 2 percent dehydration is reached, so if you're thirsty, you know you're dehydrated. This thirst response declines with age, so older adults are at greater risk of dehydration.

A better indicator is the color of your urine. Generally, lighter is better, but don't go overboard, as drinking too much fluid may put you at risk for a condition known as hyponatremia, which may be life-threatening. Symptoms of hyponatremia may include headache, confusion, nausea/ vomiting and muscle weakness or seizures.

You can also weigh yourself before and after exercise, to see how much water has been lost. If water loss during exercise is greater than 2 percent of body weight, fluids should be consumed during exercise. For example, if a 150- pound person loses more than 3 pounds after exercise, they should drink while they are working out.

If the exercise session is less than one hour, water by itself is fine.

If exercise lasts 60-90 minutes, an electrolyte replacement beverage is a good idea. Beverages with a small amount of caffeine are also OK.

Energy drinks, however, would not be recommended. New research suggests consumption of an ice slurry beverage before exercise may lower body temperature, and prolong exercise time in the heat. With the latter, practice on yourself beforehand, particularly prior to a competition, as you might overdo it and end up shivering.

There you have it... tips for staying safe in the heat. Have a great (and safe) summer!