Why is sitting too much linked with health problems? continued...
One possibility: Sitting for a long time causes muscles to burn less fat and blood to flow more sluggishly. Both can increase the risk of heart disease, high blood pressure, and other problems.
In some cases, it's still unclear which way the link goes, says Barry Braun, PhD, director of the Energy Metabolism Laboratory at the University of Massachusetts in Amherst. "People who sit the most are more likely to be obese,'' he says. “Are people obese because they sit too much, or do they sit too much because they are obese?”
How does sitting affect appetite?
You might think that sitting would make you less hungry. Braun's research has found it is not true.
His team assigned people to sit a lot one day and to stand a lot on another day. Each time, the researchers studied how it affected their appetite. ''Going from active to sitting doesn't lower your appetite or your energy intake," he says. Prolonged sitting, he says, may trigger us to eat more than we should, leading to weight gain.
Why doesn't physical activity seem to compensate?
Researchers are trying to figure out if sitting and exercise ''are two different components driving health," LaCroix says. "I am not at all certain this is true, but we are trying to figure it out."
Even though the idea is evolving, Kerr says it may help people to think about being active and sitting as two separate ways to improve or harm your health. "Does exercise compensate for a bad night's sleep?" she asks. "So why should exercise compensate for the fact that you sit all day?"
What's the take-home message from the research?
''Don't demonize sitting," LaCroix says. The message, she says, is to reduce sitting time by breaking it up. Although experts aren’t sure how often you need to get up, they suggest getting up about every 30 minutes if possible.
Kerr tells people to value some sitting time. "Sitting while you are socially engaged might be something that's very good for you," she says. Likewise, sitting for a few minutes to decompress after a stressful day could be good for you.
Think big picture, Kerr and LaCroix say, and stand when you can.