Researchers find what looks to be a proxy measure for the degree to which a person is sedentary - but of course there might be other important correlations here, such as with wealth or intelligence: "Watching TV for an average of six hours a day could shorten the viewer's life expectancy by almost five years ...The impact rivals that of other well known behavioural risk factors, such as smoking and lack of exercise, the study suggests. Sedentary behaviour - as distinct from too little exercise - is associated with a higher risk of death, particularly from heart attack or stroke. Watching TV accounts for a substantial amount of sedentary activity, but its impact on life expectancy has not been assessed, say the authors. They used previously published data on the relationship between TV viewing time and death from analyses of the Australian Diabetes, Obesity and Lifestyle Study (AusDiab), as well as Australian national population and mortality figures for 2008, to construct a lifetime risk framework. AusDiab is a national survey of a representative sample of the population, starting in 1999-2000, and involving more than 11,000 adults aged 25 or older. The authors then constructed a risk framework for the Australian population in 2008, based on the answers the survey participants had given, when quizzed about the total amount of time they had spent in the previous week watching TV or videos. ... These figures compare with the impact of other well known lifestyle factors on the risk of death from cardiovascular disease after the age of 50, including physical activity and obesity. For example, other research has shown that lifelong smoking is associated with the shortening of life expectancy by more than 4 years after the age of 50, with the average loss of life from one cigarette calculated to be 11 minutes - equivalent to half an hour of TV watching, according to the authors' risk framework." I applaud the researchers for finding a way to present their work that will likely get a lot of play in the media.