Twenty-three percent of adults globally -- and an alarming 80% of adolescents at school -- failed to be as active as they should have been in 2015, according to a new study. The potential health consequences are big, particularly for people who spend more of their day sitting.
Keeping your body stationary for prolonged periods of time can increase your chances of developing a range of diseases, including certain cancers, type 2 diabetes, cardiovascular disease and stroke.
But factoring in one hour of physical activity for each day spent sitting can offset your chances of disease, according to one of four papers that form part of the series
published Wednesday in The Lancet. The findings are the latest in a line of evidence on the dangers of sitting for too long -- but this time, they come along with a solution.
The study found that the health impacts of an eight-hour workday spent bound to a computer or in a car can be alleviated by activities as simple as cycling at speeds of more than 16 kilometers per hour (about 10 mph) or walking briskly at 5.6 kilometers per hour (about 3.5 mph) for more than 60 minutes each day.
The researchers hope this guidance will kick people and governments into action to get populations moving more.
The importance of being active
"Too many people are physically inactive and are spending long periods sitting. ... It needs to be taken much more seriously," said Ulf Ekelund, professor of physical activity and health at the Norwegian School of Sport Sciences, who led one of the studies.
"We showed that you can offset the association between prolonged sitting and mortality," he said, stressing that "physical activity can prevent almost all non-communicable diseases (such as type 2 diabetes and cardiovascular disease)."
The team analyzed data from more than 1 million people in 16 studies, mainly from Western Europe, North America and Australia, to find out how many hours of daily activity could help reduce the increased risk of death that has been linked to extended periods of time spent sitting. Data from other regions of the world were limited.
People who sat for more than eight hours and were active for less than five minutes had a 59% increased risk of death compared with a reference group of people who sat for less than four hours and were active for more than 60 minutes.
But there was some middle ground. "There was a gradient," Ekelund said. "It doesn't mean that doing 30 minutes isn't worth anything. ... It will definitely reduce the risk." But the longer the activity, the better.
Time spent watching television was also analyzed in one subgroup.
"There were similar associations" with TV, Ekelund said. "People should avoid more than two to three hours of TV viewing per day."
He highlighted the worst-case scenario as a lifestyle in which someone drove to work, sat at their desk all day and then spent a few hours of their evening watching TV. "That's a huge amount of sitting time," he said.
The bare minimum
The recommendations made in the study are double the current World Health Organization guidelines, which urge a minimum of 150 physically active minutes each week -- which people still fail to meet. In the United States, just 21% of the population meets the advised minimum, according to the Centers for Disease Control and Prevention.