Heart Health Archive

Sodium doesn't affect everyone equally, but there's good reason to stick to moderate amounts in your diet.

On average, Americans eat too much salt — more than a teaspoon and a half a day. Most often it doesn't come out of a shaker, but is hidden in the foods you eat. But is it really bad for your heart to eat too much, or is that just a concern for people with certain risk factors? There's been some debate on this topic, even among members of the scientific community. We asked Nancy Cook, a professor of medicine at Harvard Medical School, for her thoughts on salt — or more precisely, sodium, a mineral that makes up 40% of salt — and how it affects your health and your heart.

Is salt really bad for your heart?

"There is a fairly undisputed effect of sodium on blood pressure," says Cook. The effect is stronger in people with high blood pressure (hypertension), a sustained blood pressure reading of 120/80 or higher. The data for an effect on cardiovascular disease are somewhat more controversial, she says, but in general, the bulk of research does seem to link lower sodium intake with both lower blood pressure and a lower risk of cardiovascular disease.

A recent 15-year follow-up to the Veterans Affairs Diabetes Trial found that short-term intensive blood sugar control did not lead to significant reduction of risk of cardiovascular events in the long term.

Leg pain when walking that eases with rest may be a sign of peripheral artery disease, which raises risk for other cardiovascular problems. Lifestyle changes — keep walking! — and treatment help.

Nerve damage might be causing everything from low blood pressure to gastrointestinal distress without your knowing it.

Doctors have long known peripheral neuropathy as a nerve condition that causes reduced sensation, tingling, weakness, or pain in the feet and hands. But those symptoms may be just the tip of the iceberg. Doctors are now learning that neuropathy can cause many more problems.

What is peripheral neuropathy?

Peripheral neuropathy refers to damage to the peripheral nerves throughout the body. These nerves carry messages to and from the brain.

News briefs

A study published online June 10, 2019, by Circulation suggests that scaling up three healthy lifestyle changes could increase the life spans of almost 100 million people around the world. Researchers — led by a team from the Harvard T.H. Chan School of Public Health — evaluated global data on death rates, blood pressure levels, the use of blood pressure medications, sodium and trans fat intake, country, age, and gender. They estimated that a worldwide push to lower blood pressure, reduce salt intake by 30%, and eliminate the consumption of trans fat could delay more than 94 million deaths from cardiovascular disease in the next 25 years. More than half of those deaths would be among adults ages 70 or older, and more than half of all deaths would be among men. Regions that would see the most benefit are outside the United States — in East Asia, South Asia, the Pacific, and parts of Africa. But we can all benefit from the three lifestyle changes. Trans fat has already been banned in foods in the United States. But if your blood pressure isn't under control, it's time to talk to your doctor about treatment and to reduce sodium intake to well under 2 grams per day.

Image: © CatLane/Getty Images

Adding short bursts of ramped-up exercise to your workout may be good for your waistline as well as your heart health.

For decades, competitive athletes have added brief bouts of strenuous exercise to their workouts to boost their performance. Known as interval training, this practice is now moving into the mainstream, bolstered by emerging evidence of its health benefits for all sorts of people, including those with heart disease.

"There's a growing consensus that interval training helps people lose weight and may have cardiovascular benefits," says cardiologist Dr. Stephen Wiviott, associate professor of medicine at Harvard Medical School. Also known as high-intensity interval training (HIIT), these workouts alternate between periods of high-intensity and lower-intensity activity. You can do intervals during any type of exercise — walking, running, cycling, swimming, or even while doing calisthenics, such as jumping jacks, push-ups, or squats. A longtime distance runner, Dr. Wiviott started doing HIIT workouts at his local CrossFit gym about a year ago. "Even though I was exercising for shorter periods of time, I lost body fat and felt better," he says. His positive experience spurred him to explore the evidence supporting HIIT.

Ask the doctor

Q. My 2-year-old grandson has a heart murmur. His pediatrician says it's likely nothing serious and will probably disappear when he's older. What causes heart murmurs in children? Are they different than those found in adults?

A. A heart murmur refers to a noise heard through a stethoscope that occurs between the heart's regular beats. Often described as a whooshing sound, murmurs are caused by turbulent blood flow. They can be separated into two categories: functional (also called innocent or benign murmurs) and structural (also known as pathologic murmurs).

About one in five people has white-coat hypertension, which refers to blood pressure that is high in the doctor's office but normal at home. Doctors don't typically treat this condition with medication, but white-coat hypertension may increase the risk of heart attacks, stroke, and death from heart disease if left untreated. People who take blood pressure medications and still experience a blood pressure rise at the doctor's office (what's known as white-coat effect) do not appear to face higher risk of heart disease. Lifestyle changes that can help all people with high blood pressure include losing weight, exercising regularly, limiting salt, and quitting smoking.

Ongoing efforts seek to better identify and treat familial hypercholesterolemia, a leading cause of early heart attacks.

Some 35 million Americans have cholesterol values that put them at high risk for heart disease. The vast majority likely have dozens of different genetic mutations, each of which raises cholesterol by a little bit. Coupled with an unhealthy diet and not enough exercise, cholesterol creeps up slowly over time in these people.

But a small minority — about one of every 250 adults — have a genetic condition called familial hypercholesterolemia (FH). Most have a mutation in one of three key genes that provide instructions that help remove excess "bad" LDL cholesterol from the bloodstream. When one of these genes doesn't operate properly, LDL cholesterol levels can skyrocket as high as 350 milligrams per deciliter (mg/dL) — more than three times higher than the desirable level of less than 100 mg/dL. Their total cholesterol levels (which includes LDL cholesterol plus other lipids) may reach 500 mg/dL or higher.