Did you know that stroke is the third leading cause of death in the United States? Each year, more than 170,000 people die from stroke and it is the leading cause of adult disability.

As scary as this may sound, 90 percent of strokes can be prevented and there are treatments that can halt or reverse the damage caused by the stroke if administered in the short time window after symptoms first appear.

With lifestyle changes and attention to the risk factors, you can reduce your chance of ever having a stroke. By learning the warning signs of stroke, you may also be able to help a loved one who has a stroke avoid suffering disability.

What exactly is a stroke and why is it so dangerous?

Strokes occur when the flow of blood and oxygen is cut off to a portion of the brain. In this way, they are similar to heart attacks. The portion of the brain deprived of vital nutrients begins to die - about two million brain cells die every minute. A stroke can be deadly, but it will more likely cause permanent brain damage and disability.

What are the symptoms of a stroke?

The most common symptoms of stroke are:

• Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  
• Sudden confusion, trouble speaking or difficulty understanding others
  
• Sudden trouble seeing in one or both eyes
  
• Sudden dizziness, trouble walking and loss of balance or coordination
  
• Severe headache with no known cause

The key word in this list is "sudden" - one moment things are fine and the next, they aren't.

Don't ignore any of these symptoms. Call 911 immediately. When you come to the hospital by ambulance, a team of specialists will be ready to evaluate you. The time you save may greatly improve the outcome of a stroke.

Is stroke hereditary or is it due to poor lifestyle choices?

It's a bit of both. Adults over the age of 55 and those with a family history of stroke are at greater risk, as well as people with diabetes, a heart rhythm disturbance called atrial fibrillation and carotid artery disease. Lifestyle choices play a big role.

What can I do to help prevent having a stroke?

Control your blood pressure and cholesterol. High blood pressure accounts for almost half of all strokes and high cholesterol accounts for about one fifth of strokes. Diabetes and smoking also are very important risk factors that need to be controlled.

Exercise regularly (at least 30 minutes a day) and watch what and how much you eat. Eat more fruits, vegetables, grains, poultry and seafood, and less red meat, fat and salt. Limit the amount of alcohol you drink.

What can my doctor do to help me prevent a stroke?

Your doctor can help you control conditions that raise your risk of having a stroke, such as high blood pressure, high cholesterol levels and diabetes.

If your doctor recommends that you make some lifestyle changes or prescribes medications to control stroke risk factors, you must follow through on these treatments and let your doctor know how they make you feel.

If you have had a stroke warning episode (called transient ischemic attack or TIA), you have a much higher likelihood of having a stroke again in the next five years and must take your doctor's recommendations all the more seriously.

How can I tell if someone is having a stroke? What should I do to help?

One of the quickest ways to detect if someone is having a stroke is FAST: face, arms, speech and time.

• Face: Does one side of the person's face drop when you ask him or her to smile?
  
• Arms: Ask the person to raise both arms. Does one arm drift downward?
  
• Speech: Have the person try to repeat a simple sentence. Are the words slurred or incorrect?
  
• Time: If you suspect that someone has had a stroke, call 911 to get the person to the emergency room right away.

Answers provided by Ronald Hess, M.D., PAMF Neurology. Dr. Hess is the founder and former medical director of the El Camino Hospital Stroke Center.