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| Coping with the Heat by Michael Adesso |
| As I sat, sweating, at my daughter’s softball game the other day, I realized that it was probably a good time to write about what problems can arise while exercising in the heat. |
| As we exercise, our bodies produce heat from muscular activity. Environmental conditions also add to this heat load. Increased heat must be lost by the body to maintain a safe internal, or “core” temperature. |
| Our bodies use several different means to dissipate heat while exercising, with the primary methods being radiation and evaporation of sweat. As the air temperature rises into the 90’s, evaporation becomes the primary cooling mechanism. As the sweat evaporates off our skin, it provides a cooling effect. Sweat production increases sharply along with body temperature, and is an efficient way to cool our bodies. This system becomes less effective as humidity rises. |
| We also lose electrolytes in our sweat. Electrolytes are charged ions that help cells perform basic functions like muscle contraction and nerve transmission. The kidneys work to keep electrolyte levels constant in your body despite changing conditions. |
| As we lose fluids and electrolytes, the body can become dehydrated. Losing even 2% of body fluid can impair performance and lead to one of three levels of heat illness: heat cramps, heat exhaustion and heat stroke. |
| Heat Cramps: This is the most common and least serious heat related illness. The exact mechanism is unknown, but it is thought to be an electrolyte imbalance. Symptoms may include profuse sweating, and cramping in the abdominal muscles or extremities. Treatment includes resting in a cool place, restoring fluids, and gentle stretching. Do not use salt tablets, as they are absorbed slowly, irritate the stomach, and do not replace fluids. If all symptoms resolve completely, you may return to activity, monitoring for any further symptoms. If left untreated, it can lead to the next level of heat illness. |
| Heat Exhaustion: This is caused by excessive fluid or electrolyte loss. Symptoms may include weakness, dizziness, nausea/vomiting, headache, muscle aches, and fainting. Treatment includes reclining the victim in a cool environment, replenishing fluids/electrolytes, sponging with cool water, or placing ice packs at the groin and armpit regions. It is also important to monitor vital signs (breathing, pulse, blood pressure). If symptoms are not reversed or seem to worsen, follow up with medical attention. Again, this can lead to the next level of heat illness. |
| Heat Stroke: This is a true medical emergency. It occurs when all of the body’s cooling mechanisms have failed and core temperature reaches 106 degrees or higher. Sever organ damage and death can result if left untreated. Signs of heat stroke can include all of the above along with altered mental status, including bizarre behavior, confusion, disorientation, hallucinations, and unconsciousness. Symptoms develop rapidly in about 80% of cases, sometimes including rapid pulse and lowered blood pressure. |
| Call 911 and try to cool the victim by sponging the body with cool water, or using icepacks as described above. He or she should recline with feet elevated. Provide fluids if conscious. Heat stroke patients need hospitalization to recover. |
| Here are some tips to beat the heat. If you have questions on the signs and symptoms of heat illnesses, follow up with your doctor. |
| 1. Allow for acclimation. Your body may need 7-10 days to get used to working out in the heat. Gradually increase your workout intensity. |
| 2. Use sport drinks to hydrate when you can, especially if you are exercising in the heat on a regular basis. They replace the electrolytes you lose, as well as providing carbohydrates which will help fuel your muscles for activities lasting over one hour. |
| 3. Drink up. Generally consume 16 ounces of liquid two to three hours before activity, and then 8 ounces after warm up. Then ingest 8 ounces every ten to fifteen minutes during exercise. Remember to rehydrate after exercise. Do not start your next workout already low on fluids. Drink 20-24 ounces of fluid for every pound of body weight you lose through sweat. |
| 4. Change out of wet clothing if you continue to exercise. Soggy clothing impedes evaporation. |
| 5. Do not rely on thirst. It is not an accurate way to know if your body needs fluid. |
| 6. Children and the elderly are more prone to heat illness. Monitor them closely and be more conservative in their care. |
| 7. Drinking a lot of coffee and soda can dehydrate the body. Rehydrate before beginning exercise. Remember not to use drinks with more than 8% carbohydrate (fruit juices, some energy drinks, soda) as this slows down the absorption of fluids. |
| Michael Adesso, PT, ATC Director of Physical Therapy University Sports Medicine Amherst Location |