Put the remote down... say researchers.
Credit: Veer Images
PARIS: A little bit of exercise each day may boost your lifespan, while an addiction to TV could be taking years off your life, say two new studies.
In one study, more than 400,000 volunteers took part in a medical screening programme between 1996 and 2008, and were then followed for eight years on average by researchers in Taiwan.
The participants were grouped according to their daily activity levels, and hazard ratios (HR) were calculated for each group's mortality risks compared with the inactive group. Based on this, the researchers calculated each group's life expectancy.
The results, published in the current issue of The Lancet, showed that just 15 minutes of physical activity per day reduces a person's risk of death by 14% and increases their life expectancy by three years compared with inactive people.
"If the minimum amount of exercise we suggest is adhered to, mortality from heart disease, diabetes, and cancer could be reduced," said co-authors Chi-Pang Wen of Taiwan's National Health Research Institutes and Jackson Pui Man Wai of the National Taiwan Sport University. "This low volume of physical activity could play a central part in the global war against non-communicable diseases, reducing medical costs and health disparities."
Benefits for all ages
According to the results, compared with individuals who said they were physically inactive, people who were in a group of 'low-volume' exercise had a 14% reduced risk of premature death from all causes, and a 10% reduced risk of death from cancer.
The 'low volume' category applied to people whose total amount of exercise of all kinds averaged 92 minutes per week, or about 15 minutes a day. On average, their life expectancy was three years longer than inactive counterparts.
The benefits applied to all ages and to both sexes and are roughly equivalent in health impact to a successful campaign to discourage smoking, said the authors.
9.8 billion hours of TV
Separately, researchers in Australia have found that watching TV or videos for an average of six hours a day could shorten the viewer's life expectancy by almost five years.
The investigators used data from a cross-sectional survey of 11,000 Australian adults who were aged at least 25 at the turn of the millennium. The data were then checked against Australia's national population and mortality figures for 2008. The researchers estimated that in 2008 Australian adults aged 25 and older spent 9.8 billion hours in front of the small screen, and that this time was associated with 286,000 years of life that ended prematurely.
"TV viewing time may be associated with a loss of life that is comparable to other major chronic disease risk factors such as physical inactivity and obesity," the researchers, headed by Lennert Veerman of the School of Population Health at the University of Queensland, said. The report was published in the British Journal of Sports Medicine.
4.8 years less life
Every single hour of TV watched after the age of 25 shortened the viewer's life expectancy by just under 22 minutes, according to an extrapolation of these figures. In actuarial terms, an hour in front of the box had roughly the same effect on life expectancy as smoking two cigarettes.
In an extreme case, someone who spends a lifetime average of six hours a day watching TV - in the top 1% of the viewing population - can expect to live 4.8 years less than someone who does not watch TV.
The investigators point the finger at TV watching not because of the programmes themselves but because of the dangers of physical inactivity that come from prolonged spells on the sofa. A sedentary lifestyle is linked to cardiovascular disease, diabetes, excess weight and other health problems.
