Heart Health Archive

A higher-than-normal blood sugar level puts you at risk for developing diabetes and heart disease.

If you're hoping to avoid heart disease, you probably pay close attention to your blood cholesterol levels. But you also should keep an eye on your blood sugar, because an elevated blood sugar level is an early warning sign of diabetes, one of the main risk factors for cardiovascular disease.

A fasting blood sugar level of 100 to 125 milligrams per deciliter (mg/dL) means you may have a common precursor to diabetes, called prediabetes. (Normal blood sugar values range from 70 to 99 mg/dL.) An estimated one in three American adults has prediabetes, although most of them don't know it.

What is the test?

People who have leg pain when exercising may need an evaluation to make sure they have normal blood flow through their leg arteries. Normally blood pressure is similar whether it is measured in the legs or in the arms. If blood pressure is lower in the legs, it usually means that cholesterol buildup inside the leg arteries is interfering with circulation. By taking accurate blood pressure measurements at different locations along your legs, your doctors can determine if you have any arterial narrowing and, if so, where.

In order to get accurate blood pressure measurements, your doctor uses a technique called Doppler ultrasound. Doppler ultrasound is a painless way to detect blood flowing through a small artery. It uses sound waves and a type of sonar detection system to make noise when blood flow is detected. For arterial studies of the legs (called segmental Doppler pressures), Doppler ultrasound is used in place of the stethoscope that doctors usually use when taking blood pressures.

What Is It?

Cardiac catheterization is a procedure in which a heart specialist inserts a small tube (catheter) through a large blood vessel in the arm or leg, and then passes the tube into the heart. Once inside the heart, doctors use the catheter to evaluate how the heart is working by measuring pressure and oxygen levels within the heart's chambers. Through the catheter, doctors inject a special dye that provides an X-ray image of the heart's internal structure and blood flow patterns.

The procedure is often done to look for narrowed and blocked coronary arteries. The X-ray dye also is injected into each of the three largest coronary arteries. This is called coronary angiography.

What Is It?

A heart transplant is surgery in which a patient with a life-threatening heart problem receives a new, healthy heart from a person who has died. In a heart transplant, the patient who receives the new heart (the recipient) is someone who has a 30 percent or greater risk of dying within 1 year without a new heart. Although there is no absolute age limit, most transplants are performed on patients younger than 70 years old.

The person who provides the healthy heart (the donor) is usually someone who has been declared brain dead and is still on life-support machinery. Heart donors are usually younger than 50, have no history of heart problems, and do not have any infectious diseases.

What Is It?

A heart-lung transplant is surgery for someone with life-threatening heart and breathing problems. Surgeons remove the damaged heart and lungs and replace them with a healthy heart and lungs from a person who has died.

The person receiving the new heart and lungs (the recipient) is someone with a high chance of dying within one to two years without a transplant. The person providing the healthy heart and lungs (the donor) is someone who is brain dead, but still on life-support machinery.

What is the test?

A Holter monitor is a portable EKG device that records your heart rhythm over time, outside the hospital or doctor's office. Whereas a regular EKG examines your heart's electrical activity for a few seconds, the Holter monitor examines changes over a sustained period of time-usually a 24- to 48-hour period-while you go about your daily activities and even while you sleep. One type of Holter monitor, called an "event monitor," can be used to record rhythms over a longer time, such as a 30-day period. Doctors use Holter monitor or event monitor tests to evaluate symptoms that come and go and that might be related to heart-rhythm changes or coronary artery disease.

How do I prepare for the test?

Men with a lot of hair on their chest will probably have to shave it. Otherwise, there's no special preparation.

What Is It?

An implantable cardioverter defibrillator (ICD) is a potentially lifesaving medical device that is placed inside the body. An ICD treats life-threatening abnormal heart rhythms (called arrhythmias), including ventricular fibrillation, which makes the heart's large muscular chambers (the ventricles) quiver without actually squeezing and pumping. When this happens, there is no real heartbeat and not enough blood flows to the brain or other organs, including the heart. As a result, a person with ventricular fibrillation passes out and can die within minutes.

An ICD is made of two parts. The pulse generator looks like a small box. It is implanted under the skin below the collarbone. The box contains a lithium oxide battery (which lasts about five to nine years) and electrical components that analyze the heart's electrical activity. Connected to the pulse generator are one or more electrodes, which travel to the heart. When the ICD senses an abnormal heart rhythm, it administers a brief, intense electrical shock to the heart, correcting the abnormal rhythm. Many people say that the shock feels like being punched in the chest, although the amount of discomfort varies.

A sleep shortfall can be hard on your heart. Make sure you're getting enough quality snooze time.

Maybe you stay up past midnight watching TV or checking your smartphone while lounging in bed. Or perhaps you snuggle under the covers and close your eyes at a decent hour, but then toss and turn, unable to fall asleep. Whatever the reason, the results are familiar to many people — feeling unrefreshed and maybe even a bit cranky when you wake up the next morning. According to the CDC, about one in three adults doesn't get enough sleep.

"Some people have trouble falling asleep. But others choose to stay awake and end up chronically sleep deprived," says Dr. Sogol Javaheri, a sleep specialist at Harvard-affiliated Brigham and Women's Hospital. When you don't sleep enough, feeling tired and bleary-eyed is only part of the problem. People who consistently get less than six hours of sleep nightly face a higher risk of heart disease as well as other, often co-occurring conditions such as diabetes and obesity. The exact mechanisms aren't fully understood, but disruptions in blood pressure and blood sugar regulation likely play a role. Insufficient sleep also appears to raise stress hormone levels and inflammation, which also strain the heart.

Here's a host of ideas that support healthy eating and exercise habits.

This holiday season, how about giving the gift of good health? From kitchen tools to a session with a personal trainer, there are many thoughtful presents that can have a lasting impact on a person's cardiovascular health. Here are suggestions from several Harvard experts.

Kitchen tools and gadgets

"Many of my patients want to eat healthier, and one good strategy is to prepare more meals at home. Because this takes time, kitchen tools and gadgets really can be helpful," says registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital. One great time-saving tool is an Instant Pot, which works as a pressure cooker, slow cooker, yogurt maker, rice cooker, and steamer, she says.

These drugs are mainstays for preventing heart disease. Are they safe and effective in older people?

Low-dose aspirin and statins are both common, inexpensive drugs that help prevent the two root causes of most heart attacks — blood clots and cholesterol-laden plaque clogging the arteries of the heart. In recent years, a number of studies have helped experts refine their advice as to who should or should not take these medications.

However, evidence-based advice for people in their mid-70s and beyond is a bit harder to come by. Historically, most drug trials have included only a small proportion of people 75 and older, in part because there are fewer people in that age demographic. Also, older people tend to have other chronic health conditions. As such, they may be more prone to drug side effects, making doctors reluctant to enroll them in clinical trials.