As modern life becomes increasingly sedentary, a growing body of evidence suggests that prolonged sitting is detrimental to our health, even for those who exercise regularly.
In light of these findings, doctors are urging adults to reduce the amount of time they spend sitting and increase their physical activity.
But the question remains: how much movement is necessary to counteract the negative effects of a day spent sitting at a desk?
According to a recent study by exercise physiologists at Columbia University, taking just five minutes to walk every half hour during prolonged periods of sitting can offset some of the most harmful effects.
The study, published in Medicine & Science in Sports & Exercise by the American College of Sports Medicine, was led by Keith Diaz, PhD, associate professor of behavioral medicine at Columbia University Vagelos College of Physicians and Surgeons.
Diaz’s study was different from others because it tested five different “exercise snacks.” One minute of walking after 30 minutes of sitting, one minute after 60 minutes of sitting, five minutes every 30 minutes, five minutes every 60 minutes, and no walking.
“If we hadn’t compared multiple options and varied the frequency and duration of the exercise, we would have only been able to provide people with our best guesses of the optimal routine,” Diaz adds.
Each of the 11 individuals who signed up for the research came to Diaz’s lab, where they spent eight hours in an ergonomic chair, getting up only to walk on the treadmill for their recommended workout snack or use the restroom. Researchers monitored each participant to make sure they did not over- or under-exercise, and they took their blood pressure and blood sugar readings on a regular basis (key indicators of cardiovascular health). During the sessions, attendees were given regular lunches and were free to use laptops, read, and check their phones.
According to the findings of the study, the best amount of activity was five minutes of walking every thirty minutes. Only this amount drastically reduced blood pressure and blood sugar levels. Additionally, compared to sitting all day, this walking exercise dramatically changed how the subjects handled heavy meals, lowering blood sugar spikes by 58%.
Taking a one-minute walk break every 30 minutes also had a small effect on blood sugar levels throughout the day. Walking every 60 minutes, for either one minute or five minutes, had no effect on blood sugar levels.
Walking of any intensity substantially lowered blood pressure by 4–5 mmHg compared to sitting all day.
According to Diaz, “This is a sizeable decrease, comparable to the reduction you would expect from exercising daily for six months.”
During the testing, the researchers also checked the participants’ mood, how tired they were, and how well they could think. All walking schedules, with the exception of one minute per hour, resulted in significant reductions in tiredness and notable improvements in mood. None of the walking schedules had an impact on thinking.
“The effects on mood and fatigue are important,” Diaz adds. “People tend to repeat behaviors that make them feel good and that are enjoyable.”
At the moment, researchers at Columbia are testing the effects of 25 different amounts of walking on the health of a wider range of people: Most of the participants in the present research were in their 40s, 50s, or 60s and did not have high blood pressure or diabetes.
“What we know now is that for optimal health, you need to move regularly at work, in addition to a daily exercise routine,” adds Diaz. “While that may sound impractical, our findings show that even small amounts of walking spread through the workday can significantly lower your risk of heart disease and other chronic illnesses.”
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