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: Daily TV quota of 6 hours could shorten life expectancy by 5 years

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

Related Stories

Daily TV quota of 6 hours could shorten life expectancy by 5 years

August 16, 2011
Watching TV for an average of six hours a day could shorten the viewer's life expectancy by almost five years, indicates research published online in the British Journal of Sports Medicine.

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.

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

June 14, 2011
Watching television is the most common daily activity apart from work and sleep in many parts of the world, but it is time for people to change their viewing habits. According to a new study from Harvard School of Public ...

TV viewing poses greater risk than computer use for cardiovascular disease

November 16, 2011
Physical activity will definitely lower children's chances of developing cardiovascular disease down the road, but physical inactivity will not necessarily increase it. Findings from a recent Queen's University study shows ...

Recommended for you

Experts devise plan to slash unnecessary medical testing

October 17, 2017
Researchers at top hospitals in the U.S. and Canada have developed an ambitious plan to eliminate unnecessary medical testing, with the goal of reducing medical bills while improving patient outcomes, safety and satisfaction.

New study: Nearly half of US medical care comes from emergency rooms

October 17, 2017
Nearly half of all US medical care is delivered by emergency departments, according to a new study by researchers at the University of Maryland School of Medicine (UMSOM). And in recent years, the percentage of care delivered ...

No evidence that widely marketed technique to treat leaky bladder/prolapse works

October 16, 2017
There is no scientific evidence that a workout widely marketed to manage the symptoms of a leaky bladder and/or womb prolapse actually works, conclude experts in an editorial published online in the British Journal of Sports ...

Ten pence restaurant chain levy on sugary drinks linked to fall in sales

October 16, 2017
The introduction of a 10 pence levy on sugar sweetened drinks across the 'Jamie's Italian' chain of restaurants in the UK was associated with a relatively large fall in sales of these beverages of between 9 and 11 per cent, ...

New exercises help athletes manage dangerous breathing disorder

October 16, 2017
A novel set of breathing techniques developed at National Jewish Health help athletes overcome vocal cord dysfunction and improve performance during high-intensity exercise. Vocal cord dysfunction, now also referred to as ...

Learning and staying in shape key to longer lifespan, study finds

October 13, 2017
People who are overweight cut their life expectancy by two months for every extra kilogramme of weight they carry, research suggests.

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.