MINNEAPOLIS - There is a very human tendency to believe stories handed down from generation to generation, especially those that relate to lifestyle or remedies. Many of those could be classified as "Medical Myths."

"Myths" in this case are dictums that are accepted as fact, but often have no basis in fact.

Myth: Cracking knuckles

"Cracking" one's knuckles causing arthritis in later years is something a great many people believe, perhaps in the hope, that others will stop what some regard as an annoying habit.

"I do not know why anyone would want to do that," commented Mark Seaburg, M.D., an internal medicine doctor in the Blaisdell Clinic in Minneapolis of Park Nicollet. "It always gives me the creeps, but no, there is really no evidence that (it) can cause arthritis in the future. On the other hand, if it hurts while you do that, there is something wrong with your joints and you should not be doing that."

The popping sound of knuckle "cracking" is actually bubbles of gas in the joint escaping.

Myth: Heat loss from head

Minnesotans, who love being outdoors in winter, have probably been warned to always wear a hat. Many believe that most body heat is lost through the head.

"Well, that is a tricky question," said Dr. Seaburg. "You lose, perhaps 10-20% of your body heat through your head. It is a very vascular structure and a lot of heat gets lost that way. However, in the cold weather, most people wear clothing on the rest of their body, which maintains that heat. If you are cold and you are outside, put a hat on. It will help, but it is only about 10-20% (heat loss)."

Myth: Feed a cold/starve a fever

Many individuals try to use food or resisting food as a technique to cure ailments. A common adage, often heard, is "feed a cold, starve a fever."

"There is really no evidence of that on either side," said Dr. Seaburg. "If you have a fever, yes, it is important to get some rest and drink plenty of fluids to make sure you maintain hydration, but 'feeding a cold, starving a fever?' There is really no evidence, either way."

Myth: 8 Glasses of water a day

On the subject of "hydration", it is commonly held that one must consume 8 glasses of water a day to remain healthy.

"Well, for most people, all you really need to do is drink when you are thirsty," said Dr. Seaburg. "That will provide plenty of hydration for you. On the other hand, if you are exercising vigorously or sweating profusely for some reason, or, if you are at high altitude, where you lose a lot of water through your lungs, then that would be a situation where you should drink at least 8 glasses, probably more."

Myth: Chewing gum in stomach

Few human habits can rouse as much deep seated emotion as chewing gum. Some may find it annoying, others, useful. Singapore once banned chewing gum entirely. Now, it is allowed there only for "medical reasons", usually through a doctor. A persistent belief about the rubbery substance is that, if swallowed, chewing gum resides in the stomach for 7 years.

"No," said Dr. Seaburg quickly. "Chewing gum is meant for chewing. So, when you are done with it, you should spit it out, not swallow it. However, if you do (swallow it), it is not going to hurt you. It will pass through fairly quickly."

Myth: Back pain? Lie down

Back pain, particularly in the lower back, seems to be the almost universal ailment of modern times. Everything from pills to manipulation to mechanical devices are used to self-treat the pain. It is commonly believed that calling in "sick" to work and staying in bed can be a useful cure.

"Most people who have back pain have a strain of the muscle. So, it is a muscular, skeletal low back pain and they get better with time," said Dr. Seaburg. "No, bed rest is not recommended for that because of de-conditioning. The more you lay around, the worse things will be. So, it is best to be active."

Dr. Seaburg did offer one caveat. "If you have sciatica, which is a bulging disc in the back, pushing on the nerve, that IS an indication for some bed rest, but, not a lot, you still want to be somewhat active."Myths about medical issues abound on the internet and in the medicine cabinets and vocabularies of many cultures, families and individuals. Checking with one's own physician is the only, sane way to gauge their validity.

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