Cutting daily sitting time to under 3 hours might extend life by 2 years

July 9, 2012

Restricting the amount of time spent seated every day to less than 3 hours might boost the life expectancy of US adults by an extra 2 years, indicates an analysis of published research in the online journal BMJ Open.

And cutting down TV viewing to less than 2 hours every day might extend life by almost 1.4 years, the findings suggest.

Several previous studies have linked extended periods spent sitting down and/or to , such as diabetes and death from /stroke.

The researchers used data collected for the National Health and (NHANES) for 2005/6 and 2009/10, to calculate the amount of time US adults spent watching TV and sitting down on a daily basis.

NHANES regularly surveys a large of the US population on various aspects of their health and lifestyle.

They trawled the research database MEDLINE, looking for published studies on sitting time and deaths from all causes, and pooled the different relative risk data from the five relevant studies, involving almost 167,000 adults. The database was then reanalysed, taking account of age and sex.

They combined these data and the NHANES figures to come up with a population attributable fraction (PAF) - an estimate of the theoretical effects of a risk factor at a population, rather than an individual level - to calculate the number of deaths associated with time spent sitting down.

The PAFs for deaths from all causes linked to sitting time and TV viewing were 27% and 19%, respectively.

The results of life table analyses indicates that cutting the amount of time spent sitting down every day to under three hours would add an extra two years to life expectancy.

Similarly, restricting time spent watching TV to under two hours daily would extend life expectancy by an extra 1.38 years.

The authors emphasise that their analysis assumes a causal association rather than proving that there is one. But they point to the evidence showing the detrimental effect of a sedentary lifestyle on health.

And they caution that their findings should not be interpreted as meaning that someone who leads a more sedentary lifestyle can expect to live two or 1.4 years less than someone who is more active.

"The results of this study indicate that extended and TV viewing may have the potential to reduce life expectancy in the USA," they write.

"Given that the results from objective monitoring of sedentary time in NHANES has indicated that adults spend an average of 55% of their day engaged in sedentary pursuits, a significant shift in behaviour change at the population level is required to make demonstrable improvements in ," they conclude.

Further research will be required before recommendations on safe levels of sedentary behaviour can be made, they add.

Explore further: Prolonged TV viewing linked to increased risk of type 2 diabetes, cardiovascular disease

More information: Sedentary behaviour and life expectancy in the USA: a cause-deleted life table analysis, doi:10.1136/bmjopen-2012-000828

Related Stories

Diabetes risk from sitting around

March 2, 2012

A new study has found that women who stay seated for long periods of time every day are more prone to developing type 2 diabetes, but that a similar link wasn't found in men.

Recommended for you

Bright lighting encourages healthy food choices

May 26, 2016

Dining in dimly lit restaurants has been linked to eating slowly and ultimately eating less than in brighter restaurants, but does lighting also impact how healthfully we order?

Big Data can save lives, says leading cancer expert

May 16, 2016

The sharing of genetic information from millions of cancer patients around the world could be key to revolutionising cancer prevention and care, according to a leading cancer expert from Queen's University Belfast.

New soap to ward off malaria carrying mosquitoes

May 13, 2016

(Medical Xpress)—Gérard Niyondiko along with colleagues Frank Langevin and Lisa Barutel has posted a project on the crowd source funding site ulule for a product called Faso Soap. They claim the soap can cut in half the ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.