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We are entering the hot and humid summer. As we age, we must be careful because our bodies no longer have the same reserve they once did, especially when we mix heat, humidity and exercise. 

We know that the body has a wonderful ability to regulate temperature. In fact, if our temperature varies much from 98.6 degrees Fahrenheit, we know something is wrong. Our cardiovascular system and sweat glands keep our temperature remarkably normal, even when it is hot and humid. If heat from the environment -- combined with heat generated by physical activity -- exceed our capacity to cool off by sweating, heat accumulates in the body. The result is a progression of increasingly menacing heat illnesses, which becomes more dangerous as we age because we lose our cardiovascular capacity to eliminate heat.
 
Exposure to heat greater than 85 degrees Fahrenheit and humid weather while performing vigorous exercise -- especially while in the sun -- is susceptible to heat-related illnesses. Other factors that make a person susceptible to heat illness include older age, heart disease, other chronic diseases, extreme exercise, sunburn, obesity, sleep deprivation, alcoholism and certain medications. Patients taking beta-blockers, tricyclic antidepressants, aspirin and diuretics are predisposed to heat disorders.

When overheated, the cardiovascular system may not be able to maintain elevated cardiac output because body fluids are lost to sweating and internal swelling. The blood vessels in the skin then collapse and the body is unable to sweat. As a result, heat cannot dissipate, causing it to build up within the body. Ultimately, serious medical consequences can result if symptoms aren't recognized and treated. Symptoms of heat stroke include weak, rapid pulse; rapid breathing; no sweating; mental signs of headache; confusion; clamminess; disturbed gait; dizziness; and in very severe cases, unconsciousness. In extreme cases, the person's temperature can be greater than 105 degrees. Less extreme temperature elevations and symptoms are categorized as dehydration and heat exhaustion or heat illness.

As we age, heat illnesses and heat stress can be prevented by taking a few precautions. The most important preventative measure is to stay hydrated with fluids that contain carbohydrates and salt. A sports drink, such as Gatorade, is good to have with you while out and about in hot, humid weather. Regular Gatorade can be diluted to taste if you are on a restricted salt diet. Alcohol should be avoided because it is a vasodilator and diuretic, which can deplete blood volume. Coffee and tea also are diuretics and should be avoided. Plain water, in excess, can lead to dilution of important electrolytes.

If you observe any of the symptoms listed above while in high temperatures, first aid should be administered immediately. Remove as much clothing as possible, spray the face and body with a mist of tepid water while fanning, and immerse in cool water if the person is conscious. If the person is alert enough, fluids should be taken by mouth and legs should be elevated 15 degrees. You also should seek shelter in an air conditioned room, if possible. Medical attention should be obtained by ambulance to a doctor or hospital. If the person is unconscious, call 911 immediately.

We live in the hot and humid south, and we are active. However, when the temperature and humidity are high and the sun is out, plan vigorous activity for cooler parts of the day. And, you should always take preventive measures. Enjoy the summer!
 
SURVIVAL TIPS FOR HEAT AND HUMIDITY

• Drink plenty of fluids, including carbohydrate-electrolyte drinks, such as Gatorade
• Wear light colored clothing made from cotton and other materials that wick perspiration
• Do not do strenuous exercise in the hottest part of the day in full sun
• Get acclimated - increase exercise gradually each day in the heat
• Avoid sunburn
• Enjoy air conditioning - that’s why it was invented

MUSCHealth.com Online Health Library Related Links:
Dehydration and Heat Stroke