When is it safe to have sex after a heart attack?

DEAR DOCTOR K: I'm a man in my 60s. I had a heart attack a few months ago, and now I'm afraid to have sex. Is it too strenuous for my heart?

DEAR READER: Your question is a common one. Many of my patients who've had a heart attack wonder if and when it will be safe to resume sexual activity. I can understand why. Physical exertion causes the heart to work harder, and if you've had a heart attack, your heart has been injured.

Does my high HDL cancel out concerns about my high LDL cholesterol?

DEAR DOCTOR K: I am 71 years old. My LDL cholesterol is 160, but my HDL is 122. Does my high HDL cancel out concerns about my high LDL cholesterol?

DEAR READER: I can't give you a definite answer for a simple reason: There are very few people like you. Therefore, there are few studies of people like you. Here's what we know. For the vast majority of people, the higher your LDL ("bad") cholesterol, the greater your risk of heart disease. In contrast, the higher your HDL ("good") cholesterol, the lower your risk.

What does pulmonary rehabilitation involve?

DEAR DOCTOR K: My doctor has recommended pulmonary rehabilitation for my COPD. What will this involve?

DEAR READER: COPD stands for "chronic obstructive pulmonary disease." This group of disorders damages the lungs and makes it increasingly difficult to breathe. Common symptoms include a mucus-producing cough, breathlessness, rapid breathing, wheezing, tightness in the chest and fatigue.

What can I do to help with my neck pain?

DEAR DOCTOR K: I work at a computer all day, and as a result, I frequently have neck pain. What can I do?

DEAR READER: Did you know that for every 10 degrees forward you tilt your head, the weight of your head on your neck increases about 10 pounds? It's no wonder, then, that bending your head over a computer all day can strain muscles, ligaments, joints and other structures in your neck.

What are the surgical options for a herniated disk?

DEAR DOCTOR K: I have a herniated disk that's been bothering me for more than a year. I've tried exercise, medication and complementary therapies. None have helped. What are my surgical options?

DEAR READER: Let's start with a brief anatomy lesson. The human spine consists of a column of interlocking bones called vertebrae. They surround and protect the spinal cord. Vertebrae are stacked on top of each other. In between each pair of vertebrae is a little shock-absorbing cushion called an intervertebral disk. Intervertebral disks -- think of miniature jelly doughnuts -- prevent the vertebrae from scraping against each other. A normal disk has a jelly-like center (the nucleus) and a tough outer covering.

What causes ulcerative colitis?

DEAR DOCTOR K: I've recently been diagnosed with ulcerative colitis. What causes it, and how is it treated?

DEAR READER: Ulcerative colitis (UC) is an inflammatory disease of the colon. (The colon is also called the large intestine.) UC can cause debilitating abdominal pain and diarrhea, and it substantially increases your risk of colon cancer.

My urine is dark with a strong smell — should I be concerned?

DEAR DOCTOR K: I sometimes have dark, strong-smelling urine. Should I be concerned?

DEAR READER: Given that this happens only occasionally, it probably is not something to worry about. But before reassuring you, I would need answers to some questions: --By dark, do you mean dark yellow? Or is your urine brown or red? If your urine is just a dark yellow color at times, especially when you don't drink enough fluids, then you don't need to worry. Dark yellow urine is a sign of dehydration.

Is it ok for my toddler to play with my iPad?

DEAR DOCTOR K: I have an 18-month-old who loves to play on my iPad. I think it's fine; my wife doesn't. What are your thoughts?

DEAR READER: The only thing I can say for sure is that I'd rather have your toddler play with your iPad than with mine. Seriously, you've asked an important question, because we see it everywhere: babies and toddlers playing with their parents' tablets or smartphones. Parents use these devices to entertain their children, and in the hope of helping them to learn.

What are signs of hypoglycemia?

DEAR DOCTOR K: I recently started taking medication for Type 2 diabetes. My doctor warned me about hypoglycemia. What signs should I look out for? What should I do if I experience them?

DEAR READER: People with Type 2 diabetes have high levels of sugar, or glucose, in their blood. Diabetes medications work to lower blood sugar to near-normal levels. But sometimes diabetes medications bring blood sugar down too low, a condition called hypoglycemia (hi-po-gly-SEE-me-uh).

Should my elderly mother switch to a geriatrician?

DEAR DOCTOR K: My mother has been going to the same doctor for decades. Now that she is 80, should she switch to a geriatrician?

DEAR READER: There's a lot to be said for a doctor-patient relationship that has built trust over the years. Switching to a geriatrician may not be a good idea -- but consulting a geriatrician could be a very good idea. Geriatricians specialize in the health of older adults.