Note: This column is for information purposes only and is not intended as a substitute for professional medical advice.

Q: In The Polio Paradox and on polio survivors' web sites I read about "cold intolerance," that polio survivors are always cold. I my feet are always cold in the winter, but I have the most trouble in summer. I get exhausted in the heat, especially when it's humid. Is heat intolerance also a post-polio problem?

A: You bet. In our 1985 National Post-Polio Survey cold caused muscle weakness in 62 percent of polio survivors, muscle pain in 60 percent, and fatigue in 39 percent. But that Survey also found that 39 percent of polio survivors have fatigue when it's hot.

Whether it's cold or hot, polio survivors have three strikes against them when it comes to controlling their body temperatures. First, the poliovirus damaged the hypothalamus, the part of the brain that serves at the body's thermostat. Second, the poliovirus killed neurons in the spinal cord that make the veins in your skin become smaller or larger as the temperature changes. Basically, polio survivors veins are always too big. When it's cold outside warm blood pools in those big veins near the surface of the skin, causing heat in the blood to radiate into the air, the skin to get very cold and to look purple or even blue. When it's hot outside, or when polio survivors take a long hot bath or spend time in a steaming Jacuzzi, the skin becomes lobster red as the veins and the arteries open wide and hot blood rushes to the skin. When polio survivors stand up gravity pulls blood into the open veins in their legs and blood pressure can drop, causing fatigue, lightheadedness or even a faint. And here's the third strike: Polio survivors who have smaller leg muscles due to polio motor neuron damage causing muscle atrophy have more blood pool in the legs, since muscle contractions help to pump blood back toward the heart.

So, since your body can't regulate its own temperature, you have to do it. Our 1983 study found that polio survivors' nerves function as if it's 20 degrees colder than the temperature of their skin. In the winter polio survivors should dress as if it's 20 degrees colder than the outside temperature. You need to dress in layers so that you can regulate your body temperature by changing the amount of insulating clothing covering your body.

But the trick is to stay warm from the get-go. You should dress right after showering when your skin is warm and red. Try wearing a heat-retaining sock liners or even long-johns made of the woven, breathable plastic fiber polypropylene. Then put on warm socks, battery-powered heated socks or ski-boot insoles, and put on the layers. (If you ever need surgery remember to remind the doctors and nurses that you get cold easily so they can provide a heated, water-filled blanket in the recovery room.)

When it's hot, stay out of the sun, move more slowly, and take more frequent rest breaks with your feet elevated to make it easier for blood to flow back to your heart so that you can prevent foot swelling and keep your blood pressure up. It's especially important to have a smaller amounts of food for lunch, have cool foods and cold drinks, and to take a feet-up break after eating, since midday is when polio survivors have the most trouble with dropping blood pressure and fatigue. (see January 2002 PPS Forum). It's also a good idea to take cooler baths or showers in summer and to keep the air conditioning turned up. It's is also as smart to cool down the car before getting in during the summer as it is heating the car up in winter. But be careful. Whether you're being chilled by a Northeast wind in November or by excessive air conditioning in August, always cover your upper body, especially your neck, to prevent muscle spasms and headaches caused by cold air blowing on your muscles.

Many polio survivors don't realize that they can have as many symptoms, and sometimes even more, during the change of seasons, when the thermometer goes up and down from day to night and from day to day. Fall and spring bring increases in symptoms, especially muscle pain and headaches, as polio survivors' temperature-challenged bodies can't decide if they should sweat to stay cool or shiver to stay warm. Layering of clothing is especially important when the world is as thermally confused as polio survivors, unable to decide what temperature it wants to be.