Are organic foods healthier than non-organic?

DEAR DOCTOR K: Many of my friends buy only organic foods. But are they really healthier than non-organic?

DEAR READER: Organic crops are grown without most synthetic fertilizers and pesticides. Organic animal products are free of antibiotics and hormones. Many people believe these foods are better for them. But we really don't know that they are.

How can I stay as active as possible as I get older?

DEAR DOCTOR K: I'm in my 80s, and I've lost some mobility over the years. How can I continue to stay as active as possible?

DEAR READER: Most of us take for granted the stamina, strength, balance, coordination and range of motion needed to perform even simple acts such as getting out of bed, heading down the stairs and walking around the block. But when we lose these basic skills, we begin to understand how much of living well relies on being able to move.

Does breath focus help to relieve stress?

DEAR DOCTOR K: A friend recommended a technique called "breath focus" to help me deal with stress. Does this help?

DEAR READER: Breath focus is a simple yet powerful technique that can elicit the "relaxation response," a state of profound peace and rest. The relaxation response was popularized by my colleague at Harvard Medical School, Dr. Herbert Benson. It has given all of us a weapon against stress.

Are cochlear implants a type of hearing aid?

DEAR DOCTOR K: I'm hard of hearing and want to learn more about cochlear implants. Are they a type of hearing aid?

DEAR READER: A cochlear implant involves several small electronic devices that are surgically implanted in the ear. It can provide sound to people who are severely hard of hearing or deaf. It is not a type of hearing aid. In fact, to be eligible for a cochlear implant, a person must have hearing loss in both ears that is so extreme that even the best hearing aid has little or no effect.

What is palliative care?

DEAR DOCTOR K: My mother was recently diagnosed with cancer. I told her to look into palliative care, but she insists that's for patients who have given up.

DEAR READER: It sounds like your mother may be confusing palliative care with hospice care. It's a common mistake. Hospice and palliative care are often talked about as if they are the same thing, but they're not.

What is interval training?

DEAR DOCTOR K: What is interval training? What are the benefits of exercising this way?

DEAR READER: Interval training simply means alternating between short bursts of intense exercise and brief periods of rest (or a less-intense activity). The payoff is improved cardiovascular fitness with shorter workouts. Aerobic activities such as walking, biking, running and swimming make the heart and lungs work harder, which increases cardiovascular endurance.

What medications treat Alzheimer’s disease?

DEAR DOCTOR K: My mother has been diagnosed with Alzheimer's disease. Can you tell me about medications that are available to treat this disease? What can and can't they do?

DEAR READER: Alzheimer's disease is a form of dementia. It often affects short-term memory early on. It then progresses to impair other cognitive functions such as thinking and judgment. As the disease advances, it can affect a person's mood and behavior. Eventually, most people lose their ability to do normal daily activities.

What is an abdominal aortic aneurysm?

DEAR DOCTOR K: I had pain in my abdomen, so my doctor did an ultrasound to check for gallstones. It turns out I have an abdominal aortic aneurysm. What is that?

DEAR READER: The aorta is the body's largest artery. It carries oxygen-rich blood from the heart to every part of the body. The aorta curves out of the heart and through the chest, then passes down the center of the body before dividing into the arteries that serve the legs.

Should I have arthroscopic knee surgery?

DEAR DOCTOR K: I'm a lifelong runner with severe knee pain. I hate the thought of surgery, but hear it's not such a big deal these days, using arthroscopy. How do I know if I'm a good candidate for it?

DEAR READER: Arthroscopy is a technique used to diagnose problems in the knees and other joints. If a problem requiring surgery is identified, arthroscopic surgery can be performed. To appreciate how valuable arthroscopic surgery is, you have to understand what things were like back in the "old days" -- like when I was in medical school.