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A painful, blistering rash known as shingles may temporarily increase a person's risk of a stroke or heart attack, according to a study in the Dec. 15, 2015 PLOS Medicine. Also known as herpes zoster, shingles results from a reactivation of the virus that causes chickenpox, which most adults had during childhood.

For the study, researchers analyzed the records of more than 67,000 people ages 65 and older diagnosed with shingles and either a heart attack or stroke from 2006 through 2011. They then compared the rates of cardiovascular events before and after a shingles attack. In the first week after a shingles diagnosis, the risk of a stroke rose 2.4 times and the risk of a heart attack increased 1.7 times compared with baseline risk.

Doing as little as 15 minutes a day can make a difference. Logging extra time helps—but only up to a point.

Regular exercise helps fend off high blood pressure, heart attacks, strokes, and a host of other chronic diseases. Despite these well-publicized benefits, most Americans aren't physically active on a daily basis. One reason may be a mistaken belief that exercise requires heart-pounding exertion and sweat. While that level of effort makes sense if you're training for a race or other athletic event, it's simply not necessary if your main concern is staying healthy.

"Unfortunately, most people have blurred the distinction between exercising for health and well-being and exercising for fitness in an athletic, competitive sense," says Dr. Harvey Simon, associate professor of medicine at Harvard-affiliated Massachusetts General Hospital. "The truth is that if you're exercising for health, it takes very little effort to see enormous benefits," he says.

Ask the doctor

Q. After some recent heart tests, my doctor said everything looked fine. But the report he sent me mentions a myocardial bridge. Should I be concerned?

A. In this condition, which is usually thought to be harmless, a segment of one of the heart's main arteries tunnels into the heart muscle and back out again instead of resting on the surface of the heart. The bridge refers to the band of heart muscle (myocardium) that stretches over that section of the artery.

Ask the doctor

Q. I'm helping my mother, who is in her late 80s, keep track of her medications, as she can be a little forgetful. Her doctor just started her on warfarin, which I've heard can interact with many different medications. What are the most common ones?

A. Warfarin (Coumadin), a widely prescribed clot-preventing drug, can be affected by many medications, but antibiotics and related drugs are the most common source of problems. One example is the antibiotic that contains sulfamethoxazole and trimethoprim (Bactrim), which is often used to treat urinary tract infections and bronchitis. It interferes directly with warfarin, heightening its anti-clotting effects, which increases the risk of dangerous bleeding.

Take an active role by checking your blood pressure with a home monitor.

Most appointments with a health care provider begin with a gentle squeeze—the sensation of a blood pressure cuff inflating around your upper arm. But that single blood pressure reading offers only a glimpse of the health of your cardiovascular system.

"When you have your blood pressure checked in the doctor's office, you're in an artificial environment that is not reflective of the vast majority of the time when your blood pressure is going through its daily excursions," says cardiologist Dr. Elliott Antman, professor of medicine at Harvard Medical School. Throughout the course of a day, the average person's systolic b-lood pressure (the first number in the reading) may fluctuate considerably.

Your primary care provider should help you control risks for heart disease and refer you to a cardiologist if needed.

Any primary care provider you see—a doctor, nurse practitioner, or physician's assistant—should offer detailed advice on how to lessen your odds of cardiovascular disease, which is responsible for one in three deaths in the United States. However, some people need more specialized care for their hearts.

"I see or hear from a lot of people who have very common problems, like high cholesterol and high blood pressure, who think they need to see a cardiologist," says Dr. Patrick O'Gara, a cardiologist at Harvard-affiliated Brigham and Women's Hospital. For many people, a primary care physician can effectively manage those problems. But if you have specific concerns, talk to your doctor about whether more specialized care might be beneficial, says Dr. O'Gara.

Implantable cardiac pacemakers help millions of people live longer and feel better.

Over the past several decades, permanent cardiac pacemakers have become a lifesaving staple of cardiovascular care. These tiny electronic devices consist of a miniature computer that is inserted under the skin of the chest. The unit sends impulses through wires (called leads) that stimulate the heart muscle to beat at regular intervals.

"There are many indications for getting a pacemaker, but nearly all involve correcting a slow heart rhythm or helping the heart to beat more efficiently," says Dr. Peter Zimetbaum, associate professor of medicine at Harvard Medical School. "In some situations, a pacemaker is needed in order to prevent death. In other cases, the device is used to improve overall heart function, which in turn also improves quality of life."

Most Americans don't get the recommended amount of these potentially heart-protecting fats.

Recently, a Harvard Heart Letter subscriber emailed us a question about omega-3 fatty acids, the unique fats abundant in many types of fish that may be linked to a lower risk of cardiovascular disease. Is there a difference, he wondered, between farm-raised and wild-caught salmon in terms of omega-3 fatty acid content?

It's a reasonable question, especially considering that wild salmon is often far more expensive than the farm-raised variety. But how much omega-3 fatty acid do we really need in our diets? And are fish the only source? Here's a brief summary of what you should know about omega-3s.

The longstanding "More Matters" campaign urges Americans to eat more fruits and vegetables (see ). Evidence to support this healthy habit keeps piling up, with the latest from a study that pooled dietary data from three large, long-term studies that followed more than 187,000 people for an average of over 20 years.

The researchers found that people who ate more whole fruits—especially apples, pears, grapes, and raisins—were less likely to develop high blood pressure than those who rarely ate those foods. As for vegetables, broccoli and carrots appeared to be the best choices for staving off high blood pressure. Fruits and vegetables provide minerals such as potassium and substances called flavonoids, both of which are linked to lower blood pressure. The study was published online in the Dec. 7, 2015, issue of Hypertension.