Watching TV a harmless habit? Wrong, study reveals seductive killer

Watching TV for more than 2½ hours a day can increase the risk of suffering a blood clot in the lung, a new study has found.

The common practice of box-set "binge-watching" seems to be the thing putting people at increased risk of lung clots, known as a pulmonary embolism.

It has been known for some time that prolonged sitting increases the risk of pulmonary embolism, said Prof Aidan Bradford, Associate Professor of Physiology at the Royal College of Surgeons in Ireland.

"The idea behind all of this is that when you're sitting down, the blood flow through the veins in your legs slows down. There is good evidence that if the blood flow through your veins slows down, you get more blood clots. "

The risk rises quickly for those who like to watch a mini series at a single sitting or back-to-back films.

The study, led by Dr Toru Shirakawa and Dr Hiroyasu Iso of Osaka University, concluded that watching TV for more than 2½ hours a day increased the risk of pulmonary embolism by 70 per cent.

Blood clots

For those participants who watched TV for more than five hours every day, the risk was 2½ times higher than for those who watched less.

The research included 86,024 Japanese participants aged between 40 and 79 years of age. The results were published on Monday evening in the journal Circulation.

“With prolonged sitting the risk of blood clots goes up. Then they flow up towards your heart and lodge in the blood vessels in your lung and that’s when you get pulmonary embolism,” said Prof Bradford.

Similar increases in risk have been found for travellers on long-distance flights.

“Sitting is sitting,” said Prof Bradford. “You have to presume that \[THESE RISKS] will also apply to any prolonged sitting situations.”

This could include people whose jobs involve long periods of sitting down at their desks, he said.

The researchers point out that small changes in watchers’ habits could reduce the risk of pulmonary embolism. “After an hour or so, stand up, stretch, walk around, or while you’re watching TV tense and relax your leg muscles for five minutes,” said Dr Iso.

Healthy weight

This advice is similar to that given to long-distance flight passengers.

Other steps to reduce risk include drinking more water and maintain a healthy weight as obesity is also linked to increased risk of pulmonary embolism.

The researchers believe that sedentary lifestyles are on the rise in Japan and this is also happening in other countries.

“Nowadays, with online video streaming, the term ‘binge-watching’ to describe viewing multiple episodes of television programmes in one sitting has become popular,” said Dr Shirakawa.

Prof Bradford noted that these results were obtained from thousands of participants followed over nearly 20 years, and have been published in the journal Circulation, which is reputable. “So you have to take the results very seriously”.

Vanesa Martinez is on placement at The Irish Times under the BSA/SFI media fellowship programme