DEAR DR. DONOHUE: I am 86 and don’t plan on getting a flu shot. I haven’t had one for more than 10 years, and I have not come down with the flu. Would you give me your unvarnished opinion on flu shots and their importance? And what are your thoughts on flu? Is it overblown? – W.T.

ANSWER: You’re foolish not to get a yearly flu shot. Older people don’t do well with the flu. Every year in the United States, 36,000 people die from flu, and most of them are older people. Flu can kill even younger people. One of my most unsettling medical experiences was witnessing a young man in his 20s die from influenza. It made me believe that the flu virus is a formidable adversary.

Flu isn’t a bad cold. It’s a serious illness. Temperature rises, and the rise can be quite high. That’s a stress on the heart. People’s throats hurt. They cough. Severe headaches are common. Muscles become very painful. Even young and otherwise healthy people take to their beds with the flu. It’s much more devastating in older citizens.

Flu vaccine isn’t perfect, but it provides protection from infection in about 80 percent of those who get it. The remainder who come down with the flu get sick but not as sick as they would be if they hadn’t had the shot.

One point worth stressing is that people do not catch flu from the vaccine. The virus in the vaccine is dead. (The virus in the nasal vaccine is alive.) A small number of people develop redness and pain at the site of the injection, but that goes away in two days. An even smaller number will experience a slight rise in temperature and mild muscle pain within six to 12 hours after getting the shot. This lasts only one or two days.

You’ve been lucky for 10 years. You’re pressing your luck by deliberately dismissing the importance of this vaccine.

DEAR DR. DONOHUE: How low does blood pressure have to go before it’s considered a problem?

I take blood pressure medicine. Occasionally my blood-pressure drops so low that I feel like I am going to pass out. Last weekend it was 60/43. My doctor doesn’t believe me because when I see him, it’s elevated. I think that must be white-coat high blood pressure. – W.H.

ANSWER: People with blood pressure lower than 120/80 live longer lives than do people with more normal readings. A low but healthy reading can be 90/60, if that pressure doesn’t cause a person to feel faint or have other symptoms.

Your pressure is quite low and you have symptoms. Something is wrong.

Record your pressure. Take those readings and your blood-pressure apparatus to your doctor’s office. Have your pressure checked on his machine and on yours. If the readings are similar, then the doctor will be forced to admit that your readings are correct.

If he rejects the readings out of hand, find another doctor.

I agree with you. Your pressure rise in the doctor’s office could well be white-coat hypertension. Your doctor sounds like he could inspire anxiety and a blood-pressure rise in just about anyone.

DEAR DR. DONOHUE: About three years ago I was diagnosed with glaucoma. I was begun on Travatan eyedrops. They gave me a headache, runny nose, sneezing and a red eye. The doctor switched me to Xalatan with the same result. Is there a medicine I can take with the drops to keep me from reacting like this? – B.J.

ANSWER: Those two eyedrops belong to the same family, and they can cause similar symptoms. However, there are many other eyedrops of different chemical structure and with different side effects. Timoptic, Ocupress and Betagan are examples.

If you can’t tolerate eyedrops, then your eye pressure can be lowered by opening the drainage passage for eye fluid either surgically or with a laser.

Glaucoma is damage to the optic nerve at the back of the eye. Lowering fluid pressure in the eye preserves the optic nerve and sight.

DEAR DR. DONOHUE: Since postage has increased, I brazenly ask a second question. In the old movies, when someone was sick, the doctor would always say, “Stick out your tongue.” What was he looking for? In all my nearly 80 years of doctor visits, I have never been asked to stick out my tongue. – K.H.

ANSWER: It’s not brazen to ask two questions, but I split them up as separate entries.

The stick-out-your-tongue-and-say-aah command took place in real life as well as in the movies. My mother used to say it at the slightest hint of illness. She said she was looking for a “coated” tongue, but I’m not sure what information that provided her.

The tongue and mouth are the sites of many illnesses. White tongues can be an infection with the yeast Candida or can be leukoplakia, a precancerous condition. Beefy red tongues indicate a vitamin B-12 deficiency. Oral cancers are common and should be looked for on all examinations. Doctors can see them without having their patients stick out their tongues.

The “aah” maneuver raises the uvula, the iciclelike appendage that hangs down from the back of the mouth’s roof. Raising it provides a better view of the throat.

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. Readers may also order health newsletters from www.rbmamall.com