context: A stroke happens when the flow of blood is cut off to part of your brain. Most are caused by a clot or something else that blocks the flow. These are called ischemic strokes. About 10% are caused by bleeding in the brain. These are hemorrhagic strokes. Older age and family history of strokes are among the things that make you more likely to have a stroke. You can't turn back the clock or change your relatives. Still, experts say 80% of strokes can be prevented. A quarter of Americans who have strokes have had one before. So what can you do to tilt the odds in your favor? High blood pressure is the No. 1 cause of strokes. It's the reason for more than half of them. A normal blood pressure reading lower than 120/80. If yours is regularly above 130/80, you might have high blood pressure, or hypertension. If it's not managed well, high blood pressure can make you 4-6 times more likely to have a stroke. This is because it can thicken the artery walls and make cholesterol or other fats build up and form plaques. If one of those breaks free, it can block your brain's blood supply. High blood pressure also can weaken arteries and make them more likely to burst, which would cause a hemorrhagic stroke. If you have high blood pressure, work with your doctor to keep your pressure in the healthy range. Medication and lifestyle changes, such as regular exercise and eating healthy, can help. You double your risk of strokes if you use tobacco. Nicotine in cigarettes raises blood pressure, and carbon monoxide in smoke lowers the amount of oxygen your blood can carry. Even breathing secondhand smoke can raise your chances of a stroke. Tobacco can also: Raise your levels of a blood fat called triglycerides Lower your levels of âgoodâ HDL cholesterol Make your blood sticky and more likely to clot Make plaque buildup more likely Thicken and narrow blood vessels and damage their linings Talk to your doctor about ways to quit smoking. Nicotine patches and counseling can help. Don't give up if you don't succeed the first time. An irregular heartbeat, called atrial fibrillation ( AFib), is behind some strokes caused by blood clots. AFib makes blood pool in your heart, where it can clot. If that clot travels to your brain, it can cause a stroke. You can have AFib because of high blood pressure, plaques in your arteries, heart failure, and other reasons. Medications, medical procedures, and surgery can get your heart back into normal rhythm. If you don't know if you have AFib but feel heart flutters or have shortness of breath, see your doctor. Too much alcohol can raise your blood pressure and your triglycerides. Limit yourself to no more than two drinks a day if you're a man and one drink if you're a woman. Drinking too much can cause AFib, too -- binge drinking (downing 4-5 drinks within 2 hours) can trigger an irregular heartbeat. High blood sugar can make you 2-4 times more likely to have a stroke. If it's not managed well, diabetes can lead to fatty deposits or clots inside your blood vessels. This can narrow the ones in your brain and neck and might cut off the blood supply to the brain. If you have diabetes, check your blood sugar regularly, take medications as prescribed, and see your doctor every few months so they can keep an eye on your levels. Being a couch potato can lead to obesity, high cholesterol, diabetes, and high blood pressure -- a recipe for stroke. So get moving. You don't have to run a marathon. It's enough to work out 30 minutes, 5 days a week. You should do enough to make you breathe hard, but not huff and puff. Talk to your doctor before you start exercising. Healthy eating can lower your risk of a stroke and help you shed weight if you need to. Load up on fresh fruits and veggies (broccoli, Brussel sprouts, and leafy greens like spinach are best) every day. Choose lean proteins and high-fiber foods. Stay away from trans and saturated fats, which can clog your arteries. Cut salt, and avoid processed foods. They're often loaded with salt, which can raise your blood pressure, and trans fats. Too much of this can clog your arteries and lead to heart attack and stroke. Keep your numbers in the healthy range: Total cholesterol: under 200 mg/d L of blood LDL (bad) cholesterol: under 100 mg/d L HDL (good) cholesterol: above 60 mg/d L If diet and exercise aren't enough to keep your cholesterol in check, your doctor may recommend medication. Loud, constant snoring may be a sign of a disorder called sleep apnea, which can make you stop breathing hundreds of times during the night. It can boost your chances a stroke by keeping you from getting enough oxygen and raising your blood pressure. If you've already had a stroke, make sure to take any medicine your doctor gives you to help prevent another one. At least 25% of people who have a stroke stop taking one or more of their drugs within 3 months. That's especially dangerous because that's when you're most likely to have another one. A low-dose aspirin every day may help prevent strokes and heart attacks. It acts as blood thinner, preventing blood clots from forming in arteries partly blocked by cholesterol and plaque. It's not for everyone, though, so don't start taking aspirin without talking to your doctor first. And don't give someone an aspirin if she's showing signs of stroke like slurred speech or a drooping face. It can make a hemorrhagic stroke worse. Instead, call 911 right away.