by Christy Halbert / June 14, 2010

Many of our gyms get hot in the summer because we don’t have (or don’t use) air conditioning. Also, many boxers participate in outdoor running routines to burn calories and/or improve overall fitness, and in the U.S., this means they’ll be running in hotter weather at summertime. With increased heat, boxers increase their risk of heat stress and heat injury. This blog will discuss heat stress, and how to prevent heat injuries while training in hot gyms and hot outdoor weather.

The human body works to regulate its temperature at a constant 98 degrees. When the body’s heat is elevated, the body produces sweat in an effort to cool the skin, and thus the body. Heat stress occurs when the body temperature rises above normal, or when the body is no longer able to regulate heat loss. Elevated heat in the body places an extra burden on the body’s cardiovascular and thermoregulatory systems. The most serious heat injuries are heat exhaustion and heat stroke.

Many factors contribute to heat stress, and these factors interact with each other, including air temperature, humidity, exposure to the sun, levels of activity and exertion, acclimation to hot weather, and intensity of the exercise.

If the ambient temperature (indoors or outdoors) is too hot, then body temperature will rise.

Humidity contributes to heat stress. Whether indoors or outdoors, in dry air sweat evaporates, and this provides the body with a cooling effect. However, in humid environments, the air will not evaporate as much, and sweat stays on the skin, increasing body temperature.

Workout intensity and length contribute to the risk of heat stress. On hot days, workouts may need to be shortened to reduce the heat load placed on the body. While anyone can suffer heat injury, the risk for heat illness or injury will increase when the exercise is too intense for the athlete.

When exercising outdoors, sunlight can quickly increase body core temperature because it warms the skin. Additionally, sunburn dehydrates the body because fluid is pulled from the body in an attempt to moisturize the skin.

Finally, the sweat that cools the skin (and body) is fluid pulled from the body, and thus sweating actually causes dehydration of the body. Sweating amplifies heat stress if the fluids are not replaced.

Boxers accustomed to hot climates can tolerate heat more easily than boxers who are accustomed to cooler climates. Boxers not acclimated to hot weather, will need to build up tolerance, slowly.

Pay attention to warning signs, and use common sense when training in hot temperatures. Ignoring warning signs will compromise recovery, and boxers won’t be able to compete or train at optimum levels. Worse, ignoring warning signs can become life-threatening. The first warning signs of dehydration and heat stress include thirst, cramping, feeling weak, or even feeing nauseated.

Warning signs of heat exhaustion include: dizziness, profuse sweating, weakness, dehydration, extreme thirst, and hot, red skin. Basic treatment for heat exhaustion: Stop the exercise. Drink cool water. Use a fan to create cool air. If outdoors, find shade and use water to cool the body. Rest.

Warning signs of heat stroke include: headache, dizziness, disorientation, nausea, dry skin, loss of color in skin, decrease or stop in sweating, fatigue, blurred vision, and fainting. The basic treatment for heat stroke is the same as heat exhaustion, but seek immediate medical assistance, because heat stroke is serious and life-threatening.

Prevention is key to avoiding heat stress and heat injury. It is far easier to prevent an injury, than to try to treat it once it has occurred. Here are a few things to keep in mind when training in hot environments:

Avoid large meals before a tough workout.
Drink water prior to exercise.
Bring a water bottle to the gym (or when outside) so that you can access cool water quickly. Drink cool water about every 20 minutes during the workout.
If going outdoors, wear light-colored clothing that is also loose-fitting so that it breathes well (cotton fabrics are a good option). Avoid direct sunlight. Use sunscreen to avoid sunburn.
If planning to run outside, remember that early morning (before 10am) and evening (after 6pm) hours will be cooler than mid-day heat.
Drink fluids after exercise to replenish the fluid lost through sweating. Remember, the weight lost during exercise is only water weight, and that water needs to be replenished.
If you feel you must drink a sports drink, dilute it with water so it is less likely to upset your stomach.
On hot or humid days, reduce the workload so you don’t push beyond your limits.
If you feel lightheaded, slow down or stop. There is a difference between pushing through a tough workout and putting yourself at risk for heat injury. It’s better to go light in a workout, and be able to train the next day, than to push through a workout, and be sidelined for a week as you recuperate.
Do not exercise with rubber, nylon, scuba or plastics on your body -- these are an extremely dangerous practice since they elevate body temperature.

Coaches may need to modify workouts, alter the time of day that outdoor running occurs, and carefully monitor athletes who are particularly large or overweight, because their bodies will not be able to cool as efficiently as slim athletes. If the gym is hot, open windows and/or make fans available to promote a cross-breeze, to help cool the air.

Following the guidelines above can reduce the risk of heat stress and make workouts more productive. Enjoy training in the summer months!