For many people, stroke—a major cause of disability and the third-leading cause of death in the US (behind heart disease and cancer)—is one of the most feared medical emergencies.

Now: There’s reason to be optimistic as new research zeros in on the best ways to prevent and treat stroke. Important new findings you should know about…

DON’T IGNORE ATRIAL FIBRILLATION

Nearly three million Americans have atrial fibrillation (AF)—a common type of irregular heartbeat that increases stroke risk substantially by promoting the formation of tiny clots that can travel through the body and lodge in blood vessels of the brain. This risk can be reduced with medication, such as blood thinners, to prevent blood clots.

New scientific finding: Research conducted by the American Heart Association found that half of people with AF are unaware of their increased risk for stroke. What’s more, a significant number of people with AF don’t even know that they have the condition, perhaps because AF doesn’t always cause noticeable symptoms.

What you can do: During your next checkup, ask your doctor whether you should be tested for AF. The condition is diagnosed with tests that include an electrocardiogram. If you experience any AF symptoms, such as heart palpitations, chest pain, dizziness, shortness of breath or lack of energy, see your doctor as soon as possible—or call 911 if symptoms are severe.

BLOOD PRESSURE—DANGER BEGINS BEFORE IT’S “HIGH”

High blood pressure (hypertension)—defined as 140/90 mmHg or above—is the leading risk factor for stroke. But growing evidence suggests that even at “prehypertensive” levels, stroke risk increases more than previously believed.

New scientific finding: A 2011 analysis of data on more than 500,000 people found that those with prehypertension—blood pressure that is above the “normal” reading of 120/80 but still below the “high” threshold of 140/90—were 55% more likely to suffer strokes in the next five to 10 years than those with normal blood pressure. The increased risk was particularly striking when blood pressure was at or above 130/85 and among people under age 65 when the study began.

What you can do: If you have prehypertension, talk to your doctor about healthy lifestyle changes—for example, lose weight if you’re overweight…cut back on salt and saturated fats…quit smoking…and exercise for at least 30 minutes daily. Important: Your ideal blood pressure may vary based on your specific medical profile, so be sure to ask your doctor for advice on your target blood pressure.

SMALL STROKES ARE A BIG DEAL

A transient ischemic attack (TIA), or “ministroke,” causes stroke symptoms (such as sudden numbness on one side of the body, dizziness, severe headache or difficulty speaking) that go away within minutes or hours, causing no lasting damage. TIAs are known to greatly increase risk for a full-blown stroke in the months to come, but recent research shows that the danger from a TIA is greater than once thought.

New scientific finding: A study conducted by Australian researchers found that people who had a TIA were 13% more likely to die in the next five years than others of the same age and 20% more likely to die in the next 10 years.

Research presented at the 2011 Canadian Stroke Congress shows that even in the short run, TIAs are more serious than they appear—nearly one-fourth of 200 people studied were clinically depressed six weeks after a TIA, and vision and thinking problems were common.

What you can do: Seek emergency care even if your stroke symptoms subside within a few minutes. The average duration of a TIA is about one minute. If you suffer a TIA, medication, such as blood thinners, can be prescribed to reduce your risk for a full-blown stroke.

CARDIAC REHAB WORKS FOR STROKE, TOO

Cardiac rehabilitation—which typically includes exercise, nutrition education, smoking cessation and counseling for stress, anxiety and depression—has long been recommended after a heart attack. Now research shows that such a rehab program could be useful for people who have suffered a ministroke.

New scientific evidence: A hundred people who had suffered TIAs during the previous year were enrolled in a traditional cardiac rehabilitation program. Seven months later, the participants had significantly reduced their risk for stroke—for example, average total cholesterol decreased by almost 12 mg/dL…and average waist circumference was cut by one inch.

What you can do: If you suffer a TIA, talk to your doctor about enrolling in a cardiac rehab program. To find such a program near you, visit the American Association of Cardiovascular and Pulmonary Rehabilitation Web site, www.aacvpr.org. Under “Resources,” click on “Resources for Patients,” then “Cardiovascular Rehab Patient Resources,” then “AACVPR Program Directory.”

DEPRESSION—TREATMENT IS CRUCIAL

Depression has long been linked to increased heart attack risk, but its relation to stroke has been unclear.

New scientific finding: In an analysis of more than 300,000 adults published in The Journal of the American Medical Association, researchers found that those who were depressed when first tested were 45% more likely than others to have a stroke at follow-up periods of two to 29 years.

It’s unclear whether depression actually leads to stroke—for example, through chemical changes that promote blood clots or by making people less likely to exercise, quit smoking or take needed medication. Nor do researchers know whether relieving depression will reduce stroke risk.

What you can do: Now that the association between depression and stroke has been discovered, it’s another compelling reason to seek treatment if you believe that you may suffer from depression.

EAT WHITE FRUITS AND VEGGIES

As part of a healthy diet, fruits and vegetables reduce the likelihood of stroke, according to several large studies. Now, new research suggests that certain kinds of produce may be better than others.

Recent scientific finding: In a study published in the journal Stroke, researchers asked more than 20,000 men and women about their consumption of various fruits and vegetables that were categorized based on the color of the edible portion. Result: The more white-colored fruits and vegetables people ate, the less likely they were to have strokes in the next 10 years.

What you can do: More research will be conducted to confirm these findings. Meanwhile, it makes sense to go ahead and include plenty of apples, pears, bananas, cauliflower, cucumbers and other white-fleshed fruits and vegetables in your diet.