DEAR DR. DONOHUE: My doctor tells me I have “pre-diabetes.” I’m not sure what that means or how it’s treated. Am I destined for diabetes? What should I be doing for it? – K.M.

ANSWER: Pre-diabetes is indicated by a fasting blood sugar that’s higher than normal but not high enough to be considered diabetes. People with it can progress to diabetes. It’s sort of a mile marker on the road to diabetes.

After a 10-hour fast, the normal blood sugar should be less than 100 mg/dL. If it’s higher than 125, then the person has diabetes. Numbers between those two values indicate pre-diabetes.

Weight loss, when indicated, is one way to get out of pre-diabetes territory. Losing only 5 percent to 7 percent of current body weight can usually bring the blood sugar down to normal ranges.

Exercise is another important way to lose the pre-diabetes label. People who spend 150 minutes a week in exercise can usually remove the pre-diabetes label. Fat blunts insulin’s ability to lower blood sugar. With less fat on board, blood sugar normalizes.

This condition is not just a hazard for developing diabetes. It also leads to heart disease. When the risks for heart disease as well as diabetes are high in a person with an abnormal fasting blood sugar, then the question of prescribing medicine comes to the fore.

The diabetes booklet explains the intricacies of this illness along with its treatment. Readers can obtain a copy of it by writing: Dr. Donohue – No. 402, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.50 U.S./$6.50 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I have noticed of late that, when I get up from a sitting position, I feel weak and have to wait for a moment until everything is normal again. During this time my heart starts to pound. I went to my heart doctor, and he said my blood pressure drops when I get up. He told me to wear surgical hose and not to worry about it. But I still worry.

Is it circulation? Could it be my heart? What can be done for it? Is there a name for it? Is it dangerous? Can I drive? – G.D.

ANSWER: The name of the condition is orthostatic (standing upright) hypotension (low blood pressure). It’s a common problem that comes with age. It is not dangerous. It doesn’t imply that you have a bad heart. It is a minor circulation misfire. You can continue to drive. There are things to do for it.

When people stand, their bodies make reflex adjustments because gravity draws blood into the legs. When everything is working perfectly, the change in position signals the heart to beat faster and signals arteries to clamp down to raise blood pressure. When this reflex action is sluggish, blood pressure falls, and there’s a transient drop in blood circulation to the brain. That causes a feeling of weakness and wooziness.

Now that you know what’s going on, you can prepare for it. Before you rise from a chair, contract your leg muscles many times. When you do rise, keep the leg muscles contracted. Those maneuvers prevent blood from pooling in the legs.

Compression hose also keep blood from stagnating in the legs.

After a person drinks one or two glasses of water, blood pressure rises within 20 minutes and stays somewhat elevated for two hours. That can counter orthostatic hypotension.

There are conditions other than aging that can be at work. As an example, water pills might take too much fluid from the body and lead to a drop in blood pressure upon rising from the sitting or lying position.

DEAR DR. DONOHUE: How do Viagra, Levitra and Cialis cause blood to flow into the penis? – G.P.

ANSWER: They relax the muscles that wrap around arteries. That, in effect, is like turning on a faucet to the wide-open position.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.