Watching six hours of television a day could shorten your life by up to five years, an Australian Study has revealed.

Sitting in front of the television for hours on end is as dangerous as smoking or being overweight according to researchers from the University of Queensland who say, " ubiquitous sedentary behavior" should be considered " a public health problem."

Australian experts constructed a model where they compared life expectancy for adults who watch TV to those who do not and found that every hour of TV watched shortened a life by 21.8 minutes.

The results published in the British Journal of Sports Medicine show that for those in the top 1 per cent  of the population who watch six hours of programs a day can expect to live 4.8 years than a person who does not watch TV and participates in more active past times.

In the study, researchers used data on 11,000 people aged 25 and older from the Australian Diabetes, Obesity and Lifestyle Study, which included survey information about how much TV people watched in a week.

"We've taken that study and translated it into what it means for life expectancy in Australia given how much TV we watch," said Dr. Lennert Veerman who led the latest research.

Too much sitting, as distinct from too little exercise, is associated with higher mortality risk, particularly from cardiovascular disease. "Logically we know that physical activity is good for health and so it's not so strange that the reverse is not so good," said Veerman.