What happens to our skin as we age?

DEAR DOCTOR K: As I've entered my 40s, the skin on my hands and face has started to change. What happens to our skin as we age?

DEAR READER: The shortest answer is that our skin gets old, like the rest of us. In fact, the three layers of skin get old in different ways. The skin's outermost layer, the epidermis, forms a protective physical barrier. The dermis, or middle layer, contains collagen and elastin, which provide strength, firmness and elasticity. It also contains blood vessels, immune cells, nerves and glands that produce sweat and oil.

How can I relieve the pain from my injured rotator cuff?

DEAR DOCTOR K: I've injured my rotator cuff. What can I do to relieve the pain?

DEAR READER: When people hear "rotator cuff injury," they often think of baseball pitchers. But most people with rotator cuff injuries are like you and me. Gradual wear and tear from everyday activities, over many years, makes all older adults vulnerable to such injuries.

My DEXA scan showed my T-score is minus 2.7– what does this mean?

DEAR DOCTOR K: I'm a 63-year-old woman, and recently I had a screening test for osteoporosis. My "T-score" was minus 2.7. What does this mean?

DEAR READER: In the past, osteoporosis -- a thinning of the bones -- was frequently diagnosed only after a bone fracture. Today, osteoporosis can be detected earlier with a bone mineral density test. Several tests can assess bone density. The most common, considered the gold standard for osteoporosis screening, is known as "dual energy X-ray absorptiometry" (DEXA). For this test, a machine sends X-rays through your bones in order to calculate bone density.

Are the new treatments for hepatitis C optimistic?

DEAR DOCTOR K: My son has a hepatitis C infection, based on a blood test. The doctor says he's OK now, but could someday become seriously ill. I hear there are new treatments for hepatitis C. Is there reason for optimism?

DEAR READER: Hepatitis C is caused by a viral infection that inflames and damages the liver. ("Hepatitis" means inflammation of the liver.) The hepatitis C virus (HCV) is usually transmitted through contact with infected blood. HCV can cause short-term (acute) or long-term (chronic) hepatitis C. Most people with acute hepatitis C eventually develop chronic hepatitis C.

What is sick sinus syndrome?

DEAR DOCTOR K: My doctor says I have "sick sinus syndrome." What is it?

DEAR READER:Your question reminded me of something that happened many years ago. A new patient came to my office. She told me that a colleague of mine had been her doctor, but she had stopped seeing him because "he didn't know what he was talking about." When I asked her to explain, she said that she had been weak and had almost fainted several times. At other times, her heart suddenly seemed to be beating too fast.

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.