24 January 2022

People who sit and watch television for more than four hours at a time may be at significantly increased risk of developing blood clots, researchers suggested recently.

An observational study published in the European Journal of Preventive Cardiology examined the association between TV viewing and venous thromboembolism (VTE).

It concluded that sitting to watch TV for four hours or more is associated with a 35% greater risk of blood clots than sitting for less than 2.5 hours. They say it is important, therefore, to take breaks by standing and stretching every 30 minutes.

Lead author Dr Setor Kunutsor, of the University of Bristol, said: “Our study findings also suggested that being physically active does not eliminate the increased risk of blood clots associated with prolonged TV watching. 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.”

The researchers conducted a systematic review to collect the available published evidence on the topic and then combined the results using meta-analysis. The analysis included three studies with a total of 131,421 participants aged 40 years and older without pre-existing VTE.

The amount of time spent watching TV was assessed by questionnaire and participants were categorised as prolonged viewers – classed as watching TV at least four hours per day – and never/seldom viewers, who watched under 2.5 hours per day.

The average duration of follow-up in the three studies ranged from 5.1 to 19.8 years, during which time 964 participants developed VTE.

When the relative risk of developing VTE in prolonged versus never/seldom TV watchers was examined, they found that prolonged viewers were 1.35 times more likely to develop VTE compared to never/seldom viewers. This was independent of age, sex, body mass index (BMI) and physical activity.

Dr Kunutsor said: “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.”

He added that while the findings are based on observational studies and do not prove that extended TV watching causes blood clots, possible reasons for the observed relationship includes the fact that prolonged TV viewing involves immobilisation which is a risk factor for VTE.

“This is why people are encouraged to move around after surgery or during a long-haul flight,” he said.

“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.”

Source: Kunutsor SK, Dey RS, Laukkanen JA. (2022) “Television viewing and venous thrombo-embolism: a systematic review and meta-analysis.” Eur J Prev Cardiol, doi:10.1093/eurjpc/zwab220.

Link: https://academic.oup.com/eurjpc/article-lookup/doi/10.1093/eurjpc/zwab220

Disclaimer: The news stories shared on this site are used as a way to inform our members and followers of updates and relevant information happening in Haematology. The BSH does not endorse the content of news items from external sources, and is not in a position to verify the findings, accuracy or the source of any studies mentioned. Any medical or drugs information is provided as an information resource only, and is not to be relied on for any diagnostic or treatment purposes.

News service provided by Englemed News http://www.englemed.co.uk/