August 23, 2021
Is your favorite downtime activity watching TV or reading on your phone or computer?
Too much leisure screen time may increase the risk of stroke among adults under age 60, according to a study published by the American Heart Association. The researchers found that eight hours or more of daily sedentary leisure time quadrupled the risk.
"Be aware that very high sedentary time with little time spent on physical activity can have adverse effects on health, including increased risk of stroke," Raed Joundi, a fellow at the University of Calgary, in Alberta, warned.
The average American adult spends more than 10 hours a day using electronic media like smartphones, computers and TV, according to the American Heart Association. Adults ages 50 to 64 years old use screens more than any other age group.Data from the AHA show that stroke-related deaths have decreased among adults ages 65 and older, but increased among younger adults. Deaths among adults ages 35-64 increased from 14.7 in every 100,000 adults in 2010 to 15.4 per 100,000 in 2016.
The majority of strokes are caused by lifestyle risk factors that can be improved — like sedentary behaviors, researchers say. Other modifiable risk factors include smoking, diabetes, diet and obesity.
"Sedentary time is increasing in the United States and Canada," Joundi said. "Sedentary time is the duration of awake activities that are done sitting or lying down. Leisure sedentary time is specific to the sedentary activities done while not at work. It is important to understand whether high amounts of sedentary time can lead to stroke in young individuals, as a stroke can cause premature death or significantly impair function and quality of life."
Joundi and his colleagues analyzed nine years of data on 143,000 Canadian adults who had no history of stroke, heart disease or cancer. Data was culled from the Canadian Community Health Survey for the years 2000, 2003, 2005, and 2007-2012.
The researchers followed the participants for an average of 9.4 years and used hospital records to identify strokes. There were 2,965 strokes reported during that time. Nearly 90% of them were ischemic, the most common type of stroke in which a blood vessel to the brain is obstructed.
The average person spent 4.08 hours of daily leisure time on screens, the study found. People age 60 and younger spent 3.9 hours a day while those ages 60-70 spent 4.4 hours. The participants age 80 and older used screens 4.3 hours a day.
Less than 4 hours a day appeared to be the sweet spot with the least health risk, the researchers reported. Overall, adults who spent 8 hours or more on leisure screen time and who were not physically active had a seven times higher risk of stroke than adults who spend 4 hours on these activities and were more active.
"Physical activity has a very important role in that it reduces the actual time spent sedentary, and it also seems to diminish the negative impact of excess sedentary time," Joundi said.
The researchers did not ask study participants about their work-related screen time which could mean that overall screen time was underreported in adults with desk jobs.
The researchers wrote that doctors and public health officials should emphasize the importance of a healthy lifestyle, including physical activity, to lower stroke risk. The American Heart Association recommends adults get at least 150 minutes, or 2.5 hours, of moderate-intensity physical activity each week.
The study was published in the the journal Stroke.