Watching television is a popular way for people to unwind but too much of that type of relaxation could be dangerous. Researchers at the University of Bristol in England found watching television 4 hours per day was associated with a 35 percent higher risk of blood clots compared to those who watched 2.5 hours or less.
As a result, study authors suggest taking breaks when binge watching in order to lessen the chances of blood clots.
"Our study findings also suggested that being physically active does not eliminate the increased risk of blood clots associated with prolonged TV watching," said lead author Dr. Setor Kunutsor of the University of Bristol, UK. "If you are going to binge on TV you need to take breaks. You can stand and stretch every 30 minutes or use a stationary bike. And avoid combining television with unhealthy snacking."
Researchers wanted to see what correlation, if any, there was between long periods of television watching and venous thromboembolism (VTE). VTE includes pulmonary embolism, which is a blood clot in the lungs, and deep vein thrombosis, which is a blood clot in a deep vein, usually the legs, which can travel to the lungs and cause pulmonary embolism.
They collected published studies on the subject and combined them to conduct a meta-analysis. "Combining multiple studies in a meta-analysis provides a larger sample and makes the results more precise and reliable than the findings of an individual study," said Dr. Kunutsor.
Researchers combined three studies with a total of more than 130,000 participants who were 40 years of age and older with no history of VTE. The amount of television watching was self-reported on a questionnaire and the participants were categorized as prolonged viewers, those who watched at least 4 hours per day, or never/seldom viewers, those who watched less than 2.5 hours per day.
The follow up period for the three studies ranged from 5 to 20 years and nearly 1,000 participants developed VTE during that time. The prolonged viewers were 1.35 times more likely to develop VTE compared to the never/seldom viewers.
"The findings indicate that regardless of physical activity, your BMI, how old you are and your gender, watching many hours of television is a risky activity with regards to developing blood clots," said Dr. Kunutsor.
He went on to say the results were just observations from the studies and do not prove extended television watching causes blood clots. However, he urged caution with excessive television time.
"Prolonged TV viewing involves immobilization which is a risk factor for VTE. This is why people are encouraged to move around after surgery or during a long-haul flight. In addition, when you sit in a cramped position for long periods, blood pools in your extremities rather than circulating and this can cause blood clots. Finally, binge-watchers tend to eat unhealthy snacks which may lead to obesity and high blood pressure which both raise the likelihood of blood clots.
"Our results suggest that we should limit the time we spend in front of the television," he added. "Long periods of TV watching should be interspersed with movement to keep the circulation going. Generally speaking, if you sit a lot in your daily life—for example your work involves sitting for hours at a computer—be sure to get up and move around from time to time."