Is it safe to swaddle a baby?

DEAR DOCTOR K: The other day I swaddled my niece before putting her down for her nap. My sister told me that's dangerous. Really?

DEAR READER: My colleague Dr. Claire McCarthy, assistant professor of pediatrics at Harvard Medical School, confirmed that your sister is right.

Should I be worried about blood test results that fall out of the normal range?

DEAR DOCTOR K: Last week I received the results of some recent blood work. A few of my values fell just outside the normal range. My doctor says it's fine, but I'm still worried. Do I need to be?

DEAR READER: A printout of lab results typically indicates normal ranges for each blood test next to your personal results. If your personal result is right in the middle of the normal range, you'll likely feel relief.

How does strength training slow bone loss?

DEAR DOCTOR K: I was recently diagnosed with osteopenia. My doctor advised strength training because it can help slow bone loss. How does it do that?

DEAR READER: Osteopenia is a thinning of the bones. It is often a precursor to osteoporosis, a more severe thinning of the bones. Osteoporosis puts you at risk for disabling, and sometimes debilitating, fractures.

Should I get a prostate cancer screening test?

DEAR DOCTOR K: I've heard so many conflicting opinions about whether or not to get screened for prostate cancer. Are there official guidelines? What do they recommend?

DEAR READER: To say that prostate cancer screening has been controversial is an understatement. I spoke to my colleague Dr. Marc Garnick, clinical professor of medicine at Harvard Medical School, to hear his thoughts.

What is a frozen shoulder?

DEAR DOCTOR K: What exactly is a frozen shoulder and can I do anything to speed up the healing process?

DEAR READER: Everyday, temporary shoulder aches and stiffness are common. Frozen shoulder is different. The shoulder starts to ache, particularly when you move it. Lifting a pan from the stovetop, brushing your hair, scratching your back -- they all hurt. So you move your shoulder less. The pain and mobility become substantially worse over time. The condition usually affects just one shoulder.

Could I have had a silent heart attack?

DEAR DOCTOR K: I recently had an ECG in preparation for a surgical procedure. The doctor said it showed I'd had a silent heart attack. How could I have had a heart attack and not known about it?

DEAR READER: I know it sounds strange. After all, on television, heart attacks are portrayed in rather dramatic fashion. Typically, you see a person clutching their chest with agonizing pain. This mental image is embedded in our culture. But my colleague, Dr. Deepak Bhatt, a cardiologist at Harvard-affiliated Brigham and Women's Hospital, cites a recent study that is the latest to show that heart attacks often can be "silent."

Do I still need to fast before a cholesterol test?

DEAR DOCTOR K: I heard that fasting will no longer be required before a cholesterol test. Will the results still be as accurate?

DEAR READER: To answer your question, I need to first describe what a "cholesterol test" is. There are three types of cholesterol that typically are measured: LDL ("bad") cholesterol, HDL ("good") cholesterol and total cholesterol (basically, the sum of LDL and HDL). There is a fourth type of fat measured at the same time: triglycerides. Most doctors order all four tests as part of what's called a "lipid (fat) panel."

Should I volunteer for a research study?

DEAR DOCTOR K: I have a particular disease. A nearby medical school is recruiting people with my condition to participate in a research study. Should I volunteer?

DEAR READER There are two good reasons to consider volunteering for a study: It might help you, and it might help others. In some types of studies, there also may be risks to you.

Can you give me some advice for measuring my blood pressure at home?

DEAR DOCTOR K: My doctor told me to check my blood pressure at home, but he didn't give me many details. Could you provide some guidance?

DEAR READER: Keeping your blood pressure in check is vital to maintaining heart health and preventing stroke. But the way most of us monitor our pressure -- by trekking to the doctor's office for occasional blood pressure checks -- is far from ideal.

Could my sinus headaches be something else?

DEAR DOCTOR K: I'm a woman in my 30s who has suffered from sinus headaches for years. Allergy medications haven't helped. What else can I try?

DEAR READER: Seasonal allergies can cause sinus congestion, sneezing and a runny nose. But when you experience pain and pressure in your head, it may be time to consider other causes. That's because sinus problems do not usually cause headaches. At least, they don't cause what most people refer to when they use the term "headache." Most people with sinus congestion refer to "head congestion," not headache.