E very 40 seconds or so, someone in the U.S. has a stroke, with adults 65 and older accounting for about two-thirds of these temporary blockages of blood flow to the brain.

“As you age, you’re more likely to ­develop risk factors such as high blood pressure, high cholesterol, and being overweight,” says Ralph Sacco, M.D., chairman of the neurology department at the University of Miami Miller School of Medicine and president of the American Academy of Neurology.

But many strokes can be avoided. In fact, 10 risk factors, which can all be lowered, are responsible for about 90 percent of strokes, according to a study published in 2016 in The Lancet. And healthy lifestyle steps are important. “Lifestyle is probably the most impor­tant thing out there and may often be more ­potent than any medication,” Sacco says. Try these strategies to reduce your risk of stroke.

Control Blood Pressure

Of the 75 million Americans who have high blood pressure, only about half have it ­under control, notes the Centers for Disease Control and Prevention (CDC).

That's important, because the Lancet study suggests that high blood pressure is responsible for 48 percent of strokes.

“High blood pressure damages the inner lining of your blood vessels, which can lead to blockage within the artery wall,” says Brian Silver, M.D., a spokesman for the American Heart Association (AHA) and professor and vice chairman of neurology at UMass Memorial Medical Center in Worcester.

What to do: Have your blood pressure checked at least once every two years or ­annually if your readings are higher than 120/80 mmHg.

If you're 60 or older and have no other cardiovascular risk factors (diabetes, high cholesterol, a smoking habit), you don’t need medication unless your systolic (top) reading is at or above 150, according to new guidelines from the American College of Physicians (ACP) and the American Academy of Family Physicians (AAFP).

You can usually control border­line blood pressure (120 to 139 over 80 to 89 mmHg) with lifestyle changes such as limiting sodium intake to 1,500 mg per day, regular exercise, and weight loss if needed.

For those at high risk for heart disease or who have a history of heart attack or stroke, and a systolic of 140 mmHg or higher, the guidelines recommend considering medication.

Manage Other Health Conditions

High cholesterol, diabetes, obstructive sleep apnea (OSA), and depression increase stroke risk to varying degrees.

What to do: If you have any of these conditions, ask your doctor to assess your heart-disease and stroke risk. (You can also check the ASCVD Risk Estimator, which uses your blood pressure and cholesterol levels, diabetes status, and several other factors to determine your 10-year risk.)

For high cholesterol, your doctor might suggest quitting smoking, losing excess weight, being more active, consuming a heart-healthy diet, drinking alcohol in moderation only, and controlling blood glucose. If this is insufficient after three to six months, consider a cholesterol-­lowering statin drug, especially if your LDL (bad) cholesterol level is higher than 190 mg/dL.

Have diabetes? Talk with your doctor about lifestyle steps, and, if needed, medication to keep your A1C (a measure of long-term glucose levels) below 7 percent, blood pressure under 130/80 mmHg, ­total cholesterol under 200 mg/dL, and LDL cholesterol under 100 mg/dL, says the National Stroke Association.

For obstructive sleep apnea, see your doctor if you snore and fit into three or more of these categories: You're male, overweight, older than 50, have a neck circumference of more than 17 inches (16 inches for women), or have constant daytime ­fatigue.

If you receive a diagnosis of mild OSA, weight loss and avoiding alcohol, cigarettes, and sedatives may be sufficient steps. For moderate and severe OSA, the most effective treatment is CPAP—continuous positive airway pressure—therapy, which blows air into your throat as you sleep.

Be aware of depression symptoms, such as exhaustion, feeling helpless or hopeless, and losing interest in activities you once enjoyed. If these last for more than two weeks, see your doctor. Mild depression may respond to an increase in physical and social activity. The next step might be cognitive behavioral therapy or, if depression doesn’t ease, medication.

Check Your Pulse Regularly

Atrial fibrillation (a-fib)—a quivering or irregular heartbeat—affects 5 percent of people older than 65 and 10 percent of those older than 80, according to the ­National Stroke Association. This can raise stroke risk by 500 percent.

What to do: Take your pulse monthly. Tell your doctor if you notice anything odd, such as a fluttering, racing, or pounding sensation in your chest. If you have a-fib, you may need an anticoagulant, or blood-thinning drug. It can reduce your risk of a first stroke by up to 80 percent, but you'll have to be monitored for complications, such as bleeding.

“Anyone over 75 with atrial fibrillation should be evaluated for treatment with an anticoagulant, as should anyone over age 65 with other risk factors, such as high blood pressure,” Silver says.

Eat for Brain Health

The Lancet study found that about 20 percent of strokes can be linked to poor eating habits. The DASH diet, a low-sodium eating plan that's packed with fruits, vegetables, and low-fat dairy, appears to reduce the risk of some strokes by 14 percent, according to a study in the journal Stroke.

What to do: Find the DASH diet here (type “DASH diet description” into the search box). Or, Sacco ­advises, simply take these steps: Limit ­sodium to 1,500 mg per day; get four to five servings of fruit and three to five servings of vegetables daily; eat fatty fish such as salmon at least twice per week; consume three to five weekly servings of unsalted nuts, seeds, or ­legumes; and avoid or limit sugary drinks to 36 ounces per week.

Keep Moving

More than one-third of strokes could be prevented by regular exercise, the Lancet study suggests. And according to a study from the University of Alabama at Birmingham published in Stroke, people who exercise at least four times per week are about 20 percent less likely to have a stroke than couch potatoes. 

What's behind these benefits? Physical activity helps you maintain a normal weight, lowers blood pressure, and improves overall blood vessel health, Sacco says.

What to do: The AHA recommends at least 150 minutes per week of moderate exercise (such as brisk walking) or 75 minutes per week of vigorous exercise (such as swimming laps or moderate jogging) for general heart health. If you have high blood pressure or cholesterol, you’ll need 40 minutes of moderate to vigorous aerobic exercise three to four times per week to reduce your stroke risk.

Avoid Air Pollution

Almost 30 percent of strokes can be tied to air pollution, according to a study published in 2016 in The Lancet Neurology. Another study, published last year in the journal Stroke, found that people who had already had a stroke were at higher risk for a second stroke when they were exposed to high levels of air pollution.

“This is one risk factor that was previously unrecognized,” says Brian Silver, M.D., the AHA spokesman. One theory is that pollution damages brain arteries, increasing the risk of a blockage.

What to do: Car emissions are a main source of air pollution, so Silver suggests trying to avoid being outside in the vicinity of busy roads. Check pollution levels and stay inside when the government's Air Quality Index is 101 or higher.

At home, use exhaust fans in bathrooms, the kitchen, and the laundry area, and nix air fresheners. Don't let others smoke around you, and if you smoke, work at quitting. And get more advice from Consumer Reports on how to keep the air in your home clean.