Stephen Hawking delivered a speech this week addressing the seriousness of obesity in an ad campaign for the Swedish nonprofit GEN-PEP.
One of the most powerful parts of the speech, as my colleague Hannah Roberts has pointed out, is perhaps when Hawking says, "For what it's worth, how being sedentary has been a major health problem is beyond my understanding."
"Today too many people die from complications related to overweight and obesity," he said. "We eat too much and move too little."
The solution is "not rocket science," Hawking said. He recommends people simply eat less and be more physically active.
Hawking has the right idea, but it isn't just about being more active. It's also about being active at the right times.
Most people think that if they have a sedentary office job, so long as they work out regularly they're in the clear. But research suggests this isn't true.
Instead, it's best to move around for at least a couple of minutes every hour.
This could be a 10-minute walk to the coffee shop down the street, a 30-second stroll into the kitchen, or simply standing up and stretching at your desk. (And while standing burns fewer calories per hour than walking, it still burns more than sitting.)
No matter what activity you do, the important thing is that you break up long periods of sitting with movement. Still, if you're looking to reap the most health benefits in those few frenetic minutes, some activities are better than others.
Walking is best
If you're a standing-desk fan, great! Standing still beats sitting, as far as overall health goes. But if awkwardly towering over your coworkers while staring at a screen isn't your thing, there's good news: Walking is superior overall.
A large recent study, for example, surveyed thousands of American adults who'd agreed to wear movement trackers. Three years later, the researchers followed up to see how their participants were doing. Some were healthy, some were ill, others had died prematurely.
In terms of this last outcome, the occasional light stroll appeared to have had a slightly protective effect — people who ambled around for roughly two minutes every hour had a 33% lower risk of dying prematurely than the people who'd stayed seated the whole time. (One caveat: Since the study was observational, meaning the researchers had no control over participants' behavior, we can't say for sure that walking reduced the risk of dying, only that the two things are related.)
Plus, when it comes to burning calories — something that's key for weight loss — walking leaves standing in the dust. One recent study, in fact, showed that people who walked, even at a fairly easy pace, burned up to three times as many calories than when they stood or sat.
The ad ends with three written statements: "Physical inactivity is now the world's fourth leading cause of death," "required physical activity per day: adults 30 minutes," and "required physical activity per day: children 60 minutes."