London, Aug 30 (IANS): Watching an average of five or more hours of television per day can block one of the key pulmonary arteries in your lungs, leading to a fatal lung condition called pulmonary embolism, researchers have said.

Prolonged television watchers have a higher risk of fatal pulmonary embolism, a condition associated with long-haul flights, found the 18-year long study in more than 86,000 people.

"The association between prolonged sitting and pulmonary embolism was first reported among air raid shelter users in London during World War II," said Toru Shirakawa, public health research fellow at Osaka University in Japan.

Nowadays, a long-haul flight in an economy class seat is a well known cause of pulmonary embolism that is called "economy class syndrome".

In the study, the length of television watching was divided into three groups: less than 2.5 hours, 2.5 to 4.9 hours and five or more hours per day.

During the follow-up period, there were 59 deaths from pulmonary embolism.

The researchers found that people whose average television viewing time was more than five hours per day had twice the risk of fatal pulmonary embolism as those who watched an average of less than two and a half hours daily.

"We found that prolonged television viewing may be a risky behaviour for death from pulmonary embolism," Shirakawa said.

Leg immobility during television viewing may in part explain the finding.

"To prevent the occurrence of pulmonary embolism, we recommend to take a break, stand up and walk around during the television viewing. Drinking water for preventing dehydration is also important," he suggested.

Prolonged computer gaming has been associated with death from pulmonary embolism "but to our knowledge, a relationship with prolonged smartphone use has not yet been reported," Shirakawa said.

The findings were presented at the ESC Congress - the annual congress of the European Society of Cardiology (ESC) - in London.