Don’t Just Sit There

Much work remains to understand what happens when we just sit for extended periods of time. The association between sitting time and health risk has been studied and published many times. A new study published in Obesity provides a reminder that we know little about causality.

Pedisic et al analyzed a cohort of more than 30,000 Australians to sort out whether obesity caused increased sitting time or increased sitting time caused obesity. To make a long story short, they found evidence that obesity might cause increased sitting time. They could not find evidence that increased sitting time caused obesity.The study has limitations. It relied on self-reported data. It did not adjust for dietary habits.

Meanwhile, we have another significant publication on a health risk associated with sitting — this time it’s the risk for certain cancers. In the Journal of the National Cancer Institute, Schmid and Leitzmann found significantly increased risk for colon, endometrial, and lung cancer in people with more sedentary time.

Most of us believe that just sitting around is not a good idea. But it’s worth remembering that we don’t have proof of causality. It’s possible that bad health causes more sitting time as much or more than sitting time causes bad health.

Intervention studies will be important to confirm our assumptions that it’s the sitting that causes all the health risks associated with it and that we can do something about it.

Many studies are underway, but we’re not there yet.

Click here for the study by Pedisic et al and click here for the study by Schmid and Leitzmann. Click here to read more about the risks of sedentary time.

Two People – Business Meeting, photograph © Stephen D / flickr

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