MEDICAL MYTHS

Following is a short list of widely believed medical myths:

1. Drink eight (or more) glasses of water each day. If there are special medical needs for specific patients, physicians may recommend such, but as a general recommendation, I believe there is no good medical evidence for the need. The "normal" person can rely on one's thirst mechanism.

2. Shaving causes your hair to grow back faster, darker or thicker. Sometimes new hair appears darker.

3. Reading in dim light ruins your eyesight. There is no good medical evidence that would indicate that this is true. Dim light can cause "strain" and uncomfortable side effects, but it does not cause permanent damage.

As a board-certified internist with several decades of experience, I believe the listed recommendations are false, and lead many people do strange things, such as bring bottled water to concerts, plays and the like.

Prolonged physical exertion, and the more so when the ambient temperature is warm, can indeed cause a need for more water, and to drink extra water under such circumstances makes sense. And, it also makes sense for the "normal" person to pay attention to his or her thirst mechanism. One's experience of thirst may lag the immediate time of extra exertion, and usually does, but a normal thirst mechanism can and will in the long run protect one from even partial dehydration.

Dallas B. Tuthill M.D.

PS The above list of three medical myths was among a list of seven "medical myths" published in the THE ORANGE COUNTY REGISTER, and republished in "FOR YOU" of the Tampa Tribune, March 14, 2009.
DBT