People who reported sitting eight or more hours daily and were not very physically active otherwise were seven times more at risk of having a stroke than people who spent fewer than four hours being sedentary and at least 10 minutes exercising each day, according to a study
published in Stroke from the American Heart Association.
Researchers included the health information of 143,000 adults from the Canadian Community Health Survey in their analysis. The scientists followed the participants, who were 40 years and older with no prior history of stroke, for an average of 9.4 years.
"Sedentary time is thought to impair glucose, lipid metabolism and blood flow, and increase inflammation in the body," said lead study author Dr. Raed Joundi, clinical scholar at McMaster University in Ontario, Canada. "These changes, over time, may have adverse effects on the blood vessels and increase the risk of heart attack and stroke."
Of the 2,965 strokes participants had during the study period, 90% were ischemic strokes. Those are the most common type of stroke, Joundi said, and they happen when an artery that supplies blood to the brain is blocked.
If the stroke isn't treated quickly, the brain cells in that area may start to die from lack of oxygen, he added.
Signs of a stroke
There are multiple signs that indicate someone may be having a stroke, said Kerry Stewart, professor of medicine at Johns Hopkins University School of Medicine in Baltimore, Maryland, who was not involved in the study.
Common symptoms include feeling weakness in your arms, legs or face, particularly if the feeling is isolated to one side of your body, he said.
Slurred speech and difficulty seeing or hearing are other signs you may be having a stroke, according to Stewart.
If you suddenly have a severe headache that isn't linked to any other known health conditions you have, that could also be a stroke symptom, he noted.
How to decrease your chances of stroke
Increasing physical activity while decreasing sedentary time can help lower your risk of stroke, Stewart said.
People can start by standing more and sitting less, he noted, and make small changes in their routine like taking the stairs instead of the elevator.
Adults should get at least 150 minutes per week
of moderate-intensity physical activity, according to the American Heart Association. Joundi said it's ideal for that activity to be in periods of more than 10 minutes at a time.
"Activities are considered moderate intensity when you are exercising enough to raise your heart rate and break a sweat, such as brisk walking or biking," he said.
has shown 10 potentially modifiable risk factors, including alcohol consumption, were associated with 90% of strokes, Joundi said, so "90% of strokes could in theory be avoided if all of these risk factors were removed in a population."
To reduce the risk of stroke, Joundi recommended people focus on more than just decreasing sedentary leisure time.
"Improving physical activity is only one important component of stroke risk reduction, together with a nutritious diet, smoking cessation, and diagnosing and treating conditions like high blood pressure and diabetes," he said.