Saturday, July 21, 2012
USA - Physical inactivity kills as many people as smoking
If ever you needed a shock to the system to make you get off your backside and into a pair of trainers, this is it: Lack of physical activity kills roughly as many people as smoking. That is the shocking message from a series of papers published this week on the health impact of inactivity.
The papers, published in The Lancet suggest that more than 5.3 million deaths would be avoided each year if all inactive people exercised, about the same toll as the 5 million deaths annually from smoking.
The deaths could have been avoided if people reached a weekly target of150 minutes or more of moderate exercise, such as brisk walking.
"We tried to estimate how many deaths would be avoided if all the inactive people in the world became active," says I-Min Lee at Harvard Medical School, head of the team that published one of the papers.
Lee analysed data from 2008 on deaths from four major illnesses that are already linked with lack of exercise – coronary heart disease, type 2 diabetes, bowel cancer and breast cancer. Her team combined data on the deaths with information on levels of exercise in each country.
From this they calculated that if everyone reached their weekly exercise targets, about 6 per cent of those who died globally from heart attacks would have survived, as would 7 per cent of those who died of type 2 diabetes, and 10 per cent of those who died from breast or colon cancer.
Harold Kohl of the University of Texas Health Sciences Center in Houston, says the figures mean that inactivity has created a modern-day "pandemic", brought on by mechanisation of everyday jobs and domestic life, the ease of transport and the prevalence of sedentary leisure pursuits, such as computer games and watching television.
"As populations have shifted towards industrialisation, mechanisation and dependency on cars, we've engineered opportunities for physical activity out of our lives, and are now killing ourselves as a result," says Kohl, lead author of another article in The Lancet, which argues for global action to reverse the situation.
In another paper, Pedro Hallal of the Federal University of Pelotas in Brazil found that globally, 42 per cent of adults spend more than four hours a day sitting, and two-thirds of adolescents spend two hours watching television without a break each day.
Hallal says that the situation shouldn't be blamed on people having a lack of motivation, but rather on the creation of environments in which it is impossible or inconvenient to move around and exercise, walk or cycle.
Forced to walk
More than 100 cities in South America have had some success combating this problem with schemes that periodically close large roads to traffic. Called the Ciclovía, the movement began 30 years ago in Bogotá, Colombia. "On 72 days of the year, 100 kilometres of city streets are closed to traffic," says Gregory Heath of the University of Tennessee in Chattanooga, who has assessed the interventions around the world that worked best to help people resume physical activity.
Heath says that at least a million people take advantage of the Ciclovía in Bogotá alone, keeping visitors active for an average of 140 to 180 minutes a week, and enabling about 14 per of the country's population to meet their weekly exercise targets.
Heath's study also revealed that pedometers, which measure the number of steps a person takes daily, are highly effective tools in motivating people to walk and exercise more. "They give feedback, so people can see how much they've done, and set targets," he says.
Unfortunately, even though the Olympics are just around the corner, they're unlikely to inspire people to exercise more.
"Olympic sports are an elite, celebrity thing, connected to national pride, but not to physical activity in everyday life," says Adrian Bauman of the University of Sydney in Australia, and author of a paper exploring what makes some people exercise but not others. His research has also shown that the Sydney Olympics in 2000 had no impact on physical activity levels in Australia. "Elite sports are not the way to slow the physical inactivity pandemic," he says.
One answer, Bauman says, is for schools to focus less on producing prizewinning athletes and more on priming all pupils to pursue physical activities that they can enjoy for the rest of their lives.