How Much Exercise Do You Need to Make Up For Sitting All Day?
Adam Rifkin stashed this in #health
An hour of moderate activity a day wipes out all the negative impacts of sedentary behavior—contrary to some prior studies claiming exercise didn’t help much at all.
“Our message is a positive one,” lead author Ulf Ekelund, of the Norwegian School of Sports Science and the University of Cambridge, said in a statement. “It is possible to reduce, or even eliminate, these risks if we are active enough, even without having to take up sports or go to the gym.”
The study is part of a new four-paper series published today in The Lancet, along with several commentaries, timed to appear just before the start of the Olympic games. That’s not a coincidence. It’s a follow-up to a 2012 series in The Lancet declaring physical inactivity a “global pandemic,” and estimating that 5.3 million people die each year due to inactivity. The 2016 series examines how much progress has been made over the last four years to counter this. [You can listen to a full Lancet podcast about the whole series here.]
Sitting for long periods—as many of us do for work—and binge-watching TV is the new smoking when it comes to human health risks. Over the last few years, there have been countless studies claiming links between our sedentary lifestyles and heart attacks, kidney diseases, chronic diseases, and colorectal cancer. Others warned that this behavior shortens our life expectancy and gives us mental health issues. And even for those who exercise regularly, a 2014 Mayo Clinic study found that every hour you sit reduces the gains of your daily workout by eight percent.
Now for the good news: that last bit might not be true after all. Earlier this year, yet another study, this time by researchers from the University of Leicester, found that people who exercise regularly really do offset the unhealthy side effects of sitting all day. And the latest meta-analysis published today in The Lancet supports that conclusion.
Granted, an hour a day of moderate exercise is twice the amount of exercise recommended by the current World Health Organization (WHO) guidelines. Even 30 minutes a day can be beneficial, but if you really want to offset all that sitting and binge-watching, the researchers agreed that you’ll need to double that. This doesn’t mean intense gym workouts or hardcore training for marathons. Anything that boosts your heart rate qualifies, including a nice brisk walk to work or leisurely bike ride.
Bear in mind that this is a meta-analysis of prior research. According to Ekelund, he and his colleagues first combed through the existing scientific literature and picked out 13 studies relating to how much time people spend sitting and mortality (defined as premature death). Then they contacted the original authors and asked them all to reanalyze their data using the same parameters. This gave them a huge sample size: over 1 million subjects in all.