man using smartphone

Too much sitting is associated with poor health outcomes, including an increased risk of some types of cancer in women. A new study published this week in the Journal of Internet Medical Research provides some evidence that a simple smartphone intervention might reduce sedentary behavior.

Study participants carried smartphones and wore accelerometers, which measure movement, for seven days. They received prompts throughout the day to answer activity-related questions such as, “What are you doing right now?” Those who selected “sitting,” or who reported that they sat for at least two hours the previous day, got a short message that encouraged them to stand up, sit less, and move more. Participants who received the intervention spent about 25 fewer minutes being sedentary than the control group.

Darla Kendzor, PhD, of the University of Oklahoma Health Sciences Center, and Kerem Shuval, PhD, MPH, director of physical activity and nutrition research at the American Cancer Society, co-led the study.

Despite the many fitness apps and wearable activity trackers on the market, Kendzor says there is a dearth of evidence-based options to reduce sedentary behavior. “Activity trackers and apps seem like they would be helpful to people who are motivated to use them, but we don’t really know whether they will work for people in general,” says Kendzor, who was funded by a grant from the American Cancer Society.

She adds that an intervention to reduce sedentary behavior has the potential to have an important public health impact because people spend so much of their time engaged in sedentary behavior. “When you think about a 24-hour period as a pie chart, moderate and vigorous activity is a tiny slice of the pie. Most of it is sedentary and light activity,” Kendzor says. “Just being able to push people from sedentary to light activity could make a big difference.”

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