High blood pressure is the main culprit.
When pressure builds up in a person's blood vessels, the extra stress on their arteries can make it challenging for the brain to get the oxygen-rich blood it needs. Over time, this can lead to a stroke.
Fortunately, there's a lot you can do to lower your blood pressure, like exercising regularly, eating healthy food, and breathing clean air.
Heavy drinking increases blood pressure, making strokes more likely.
A major study published in The Lancet this week showed that the more we drink, the higher our blood pressure and risk of stroke. The researchers analyzed health data from 500,000 Chinese men and over 10 years, and found that people who drank less had lower blood pressure and a reduced risk of stroke. Overall, the researchers found that the risk of having a stroke increases by 35% for every four alcoholic drinks consumed per day.
The National Stroke Association recommends "no more than two drinks a day for men, and one drink a day for women."
Smokers double their risk of a stroke.
The chemicals in tobacco can cause people's arteries to narrow and can also damage the lining of their artery walls, prompting a spike in blood pressure.
When a smoker inhales, the action triggers an immediate blood-pressure spike, and smokers can develop long-lasting problems in their blood vessels over time.
"Smoking increases clot formation, thickens blood, and increases the amount of plaque buildup in the arteries," according to the National Stroke Association.
Breathing polluted air can also prompt more strokes.
A 2016 study of stroke patients in 188 countries around the world found that air pollution is a serious risk factor for these brain attacks, especially in middle- and low- income countries.
Around the globe, bad air — which can include household air pollution from cook-stoves and wood fires — accounts for almost a third of stroke-related disabilities.
Being overweight can make a stroke more likely, too.
Carrying more fatty tissue around in the body makes it trickier for arteries to expand and tougher for blood to flow swiftly through the body to the brain. Health problems that normally go hand in hand with extra weight, like blood clots, narrowed arteries, and high cholesterol can all contribute to a person's stroke risk.
Taking a look at your mid-section is a good way to assess where you stand in this regard: A large waist circumference is a better measure of stroke risk than a person's height and weight.
Lounging around all day is also a risky behavior that can lead to more strokes.
The good news is that you don't have to move around much to make an impact.
Studies show that even about 25 minutes of moderate activity each day helps decrease a person's stroke risk. No need to run a marathon.
One study of more than 61,000 California teachers (all women) showed that those who got at least 150 minutes of exercise each week were 30% less likely to have an ischemic stroke than those who were less active. That translates to just 21 minutes per day.
Evidence also suggests that the simple act of going for a walk every day can make a stroke milder if a person does have one. A 2018 study of Norwegian people in their 70s found that those who walked and swam on a regular basis had less severe strokes than Norwegians who don't move around much.
In addition to keeping our blood vessels pumping swiftly, exercise can create more oxygen-rich blood and prompt our muscles to grow more blood vessels. Conversely, not moving around can put people at risk for developing chronic conditions like high blood pressure, which in turn can make strokes more likely.
Not eating enough fresh foods, like colorful vegetables, fish, and nuts, increases stroke risk as well.
Studies show time and again that people whose diets are rich in fruit, vegetables, and fish have fewer strokes.
For women, researchers have noticed that those who adhere to a Mediterranean diet — which includes plenty of olive oil, whole grains, beans, chicken, and fresh vegetables — are far less likely to suffer strokes than other women. A recent 17-year study of women over 40 years old in the UK found that those who followed a Mediterranean diet (according to their 7-day food diaries) had 22% fewer strokes.
This was true even for people who were already at risk for heart disease.
Diabetes, both Type 1 and Type 2, can prompt dangerous glucose buildups in the bloodstream that make strokes more likely.
People with diabetes have a hard time making insulin in their pancreas. Insulin is the key hormone that turns glucose from the foods we eat into energy our body can use.
When the body doesn't produce enough insulin and glucose builds up in the blood, it can lead to dangerous fatty deposits and clots in a person's blood vessels. Over time, those clots may cut off the blood supply to a person's neck and brain, prompting a stroke.
Strokes are two to four times more common in people with diabetes.
Your genes also play a role.
Sometimes, the things you can do to prevent strokes only go so far. Scientists have lots of evidence that our genes contribute to stroke risk in big ways.
In a recent study of 306,473 white British men and women, people who had genomes associated with higher genetic stroke risk were 35% more likely to have a stroke than people with some of the lowest genetic risks. That was true no matter what their lifestyle looked like.
Still our actions are often more powerful than our genes when it comes to preventing strokes: lifestyle factors like smoking, unhealthy eating, and lack of exercise were associated with a 66% increase in stroke risk in that study, no matter what people's genes were like.
Getting old — another factor we don't have much control over — makes strokes more common as well.
As we grow old, our arteries harden and stiffen, making strokes more likely for everyone.
This is part of the reason why women have more strokes than men: they tend to live longer.
Not getting enough sleep is bad for your brain in many ways. Increased stroke risk is one of them.
Not catching enough zzz's can put people at risk of developing all kinds health problems, including strokes. Seven to eight solid hours of shut-eye each night is the right dose for most people.
One study of Swedish men over 50 suggests that sleeping less than five hours a night is as bad for you as smoking when it comes to stroke risk
But new evidence suggests that regularly taking a short daytime nap can help your body stay stroke-free, too.
In research announced at a meeting of the American College of Cardiology in March, scientists found that people who opt for a mid-day snooze maintain lower blood-pressure levels. Researchers think this naptime routine may help lower blood pressure just as well as other remedies, like cutting out alcohol or taking a low-dose medication. More research is needed to know for sure whether it's really the naps that cause the blood pressure benefit, though.
