Limiting TV watching to one hour or less per day may help reduce the risk of heart attacks, strokes, and other blood vessel diseases, even for people who have a high genetic risk for Type 2 diabetes. This is the key finding of a new study published in the Journal of the American Heart Association.
Atherosclerotic cardiovascular disease (ASCVD) is a serious condition caused by plaque buildup in the arteries, leading to heart disease, strokes, and poor circulation. In severe cases, it can result in bypass surgeries, amputations, and premature death.
Researchers have long known that both Type 2 diabetes and a sedentary lifestyle, including prolonged sitting, are major risk factors for ASCVD. This study is one of the first to explore how genetic risk for diabetes interacts with TV-watching habits in determining future heart disease risk.
TV Watching and Heart Health
The study was led by Dr. Youngwon Kim, a professor at the University of Hong Kong. “Watching TV makes up a significant portion of daily sitting time, and it has been consistently linked to a higher risk of diabetes and heart disease,” Dr. Kim explained.
“Our study provides new evidence that reducing TV time could be an effective way to lower the risk of cardiovascular diseases, particularly in people who are genetically prone to diabetes.”
Researchers analyzed data from 346,916 adults in the U.K., with an average age of 56 years, and tracked their health outcomes over nearly 14 years. During this time, 21,265 participants developed ASCVD.
Each participant was assigned a polygenic risk score, a measure of their genetic likelihood of developing Type 2 diabetes based on 138 known genetic variants. They were then grouped into three categories of genetic risk: low, medium, and high.
The researchers also categorized participants based on their self-reported TV-watching habits: those who watched one hour or less per day and those who watched two or more hours per day.
Key Findings
The study found:
TV time matters: People who watched two or more hours of TV per day had a 12% higher risk of developing ASCVD compared to those who limited their TV time to one hour or less, regardless of their genetic risk for diabetes.
Lower TV time may help high-risk individuals: People with a high genetic risk for Type 2 diabetes who watched one hour or less of TV daily had a lower 10-year risk of developing ASCVD (2.13%) compared to people with a low genetic risk who watched two or more hours daily (2.46%).
Genetics is not destiny: Even those with a high genetic risk for diabetes did not see an increased risk of heart disease as long as they kept their TV viewing time to one hour or less per day.
Dr. Mengyao Wang, the study’s first author and a recent Ph.D. graduate from the University of Hong Kong, emphasized the importance of these findings.
“People with a high genetic risk for Type 2 diabetes can significantly lower their chances of developing heart disease and stroke by simply reducing their TV time. This suggests that limiting TV viewing could be an effective lifestyle change for preventing cardiovascular diseases,” she said.
Implications for Health and Prevention
Experts believe these findings reinforce the importance of reducing sedentary behaviors. Dr. Damon Swift, an associate professor at the University of Virginia and chair of the American Heart Association’s Physical Activity Committee, commented on the study.
“This research highlights how small lifestyle changes, like watching less TV, can improve heart health for everyone, including those at high genetic risk for diabetes.”
Swift also pointed out that long periods of sitting—whether at home or at work—can be harmful, and interventions should focus on helping people break up their sedentary time with more movement.
Limitations and Future Research
While the study involved a large number of participants, most were white British adults, meaning the results may not apply to other ethnic groups or people in different countries. Future studies will need to examine whether the same relationship between TV time, genetics, and heart disease risk holds true for more diverse populations.
Overall, this research adds to growing evidence that reducing screen time and staying active can be simple yet powerful steps toward better heart health.
If you care about stroke, please read studies about how to eat to prevent stroke, and diets high in flavonoids could help reduce stroke risk.
For more information about health, please see recent studies about how Mediterranean diet could protect your brain health, and wild blueberries can benefit your heart and brain.
The research findings can be found in the Journal of the American Heart Association.
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