Any advice for eating healthy when cooking for one?

DEAR DOCTOR K: I'm 84. My doctor is concerned about my declining weight. But ever since my husband passed away last year, I haven't been very motivated to cook. Any advice?

DEAR READER: I see this with my patients quite often. The sadness and depression that follow the loss of a loved one can cause apathy. After years of cooking for two, it can be hard to make the effort to prepare regular, nutritious meals for one.

I have painful knees. Is swimming a good exercise option for me?

DEAR DOCTOR K: I'm overweight, and I want to exercise. But I have painful knees that make it difficult to walk. Is swimming a good alternative?

DEAR READER: In terms of convenience, it's hard to beat brisk walking as a form of exercise. You don't need any special equipment or venue, and you can do it in many places. But during the winter, harsh weather can make walking outdoors unpleasant -- even treacherous at times. And for some people -- such as those with achy knees, sore hips or substantial weight -- walking may be uncomfortable.

Why does my doctor think I don’t need an angioplasty and stent?

DEAR DOCTOR K: A test showed a 50 percent blockage in one of my coronary arteries. That sounds pretty bad to me. But the cardiologist said I didn't need an angioplasty and stent. Why?

DEAR READER: Coronary arteries send needed blood to the heart muscle. That blood flow can be blocked by cholesterol-rich plaques of atherosclerosis. When the blockage seriously reduces blood flow, it increases your risk of a heart attack. An angioplasty and stents can be helpful for restoring blood flow, but the procedure is not risk-free.

Does my son need to get the HPV vaccine?

DEAR DOCTOR K: A friend says that my young son should get the vaccine that protects girls against cervical cancer. That doesn't seem to make sense. Can you explain?

DEAR READER: Your friend is right, and here's why. The vaccine is against a virus called human papilloma virus (HPV). There are more than 100 strains of HPV; about 40 of these strains can be transmitted by sexual contact. So-called low-risk strains cause genital warts. High-risk strains can cause cancers of the cervix, anus, penis and throat. I'll call these the HPV-related cancers. Not all of these cancers are caused only by HPV, but the virus is an important cause of each. Most cases of cervical cancer in women in the United States are caused by HPV.

Why are pediatricians screening teens for high cholesterol and HIV?

DEAR DOCTOR K: A friend of mine just took her teenager to the doctor for a checkup. The girl's cholesterol was checked, and she was tested for HIV. What's going on? Will my teenage daughter's pediatrician do the same?

DEAR READER: The yearly checkup is the perfect time for a doctor to see how kids are growing and give any needed shots. But it's also an important time to see how they are doing more generally, and to help ensure that they grow into healthy, happy adults.

Can mindfulness be used for more than stress reduction?

DEAR DOCTOR K: I can't turn around without hearing about mindfulness these days. Is it just for stress reduction, or is there more to it?

DEAR READER: Mindfulness may have started out as a meditation technique. But now it is being used for everything from boosting happiness to treating high blood pressure. It's been shown to help treat depression and anxiety and improve sleep quality. And it's being studied as a complementary therapy for cancer, stroke, multiple sclerosis and pain.

My middle schooler struggles with academics despite his best efforts. Could he have a learning disability?

DEAR DOCTOR K: My middle-schooler spends a lot of time studying. But his grades have dropped, and I see him getting more and more frustrated. What could be going on, and what can I do?

DEAR READER: Many children have problems with schoolwork or homework at one time or another. These problems usually do not last long. But if your son is still getting poor grades (C or below) despite working hard, it could be a sign that your son has a learning disability or some other problem that needs help.

Are there any good surgical options to treat emphysema?

DEAR DOCTOR K: My mother has severe emphysema. Medication and oxygen therapy aren't helping much anymore. Are there any good surgical options?

DEAR READER: Emphysema is a long-term lung problem that makes it harder and harder to breathe as the disease progresses. It is often grouped together with chronic bronchitis under the label of chronic obstructive pulmonary disease (COPD).