Part II: A New Formula for How Long We Should Spend Sitting & Standing in a Workday
By Sumathi Reddy
Other research aims to find ways to mitigate the adverse effects of too much sitting. A curious study, published last week in the American Journal of Preventive Medicine, looked at fidgeting. The researchers examined data from the UK Women’s Cohort Study, which has followed a large group of women for about 20 years. Nearly 13,000 of the women were asked to rate on a scale of 1 to 10 how much they fidget. Among women who were rated as the most sedentary, those who fidgeted a lot had the same risk of dying as those who weren’t especially sedentary. But women who didn’t fidget had an increased risk for mortality.
Janet Cade, professor of nutritional epidemiology at the University of Leeds, in England, and senior author of the paper, said the study found an association between the two factors and didn’t prove causality.
“In order to get benefits from nonsedentary behavior maybe you don’t have to go out and run a marathon,” Dr. Cade said. “Maybe you can do small amounts of movement and that would give you some benefit.”
Various studies have shown that even regular exercise won’t compensate for the negative effects from sitting too much during the day. Sitting causes physiological changes in the body, and may trigger some genetic factors that are linked to inflammation and chronic conditions such as diabetes and cardiovascular disease, said Dr. Buckley, of the University of Chester. In contrast, standing activates muscles so excess amounts of blood glucose don’t hang around in the bloodstream and are instead absorbed in the muscles, he said.
Standing burns one-half to one calorie more a minute than sitting. In four hours, that represents as many as 240 additional calories burned. Sitting more than an hour lowers the levels of the enzyme lipoprotein lipase, which causes calories to be sent to fat stores rather than to muscle, Dr. Hedge said.
The effects of prolonged sitting on blood flow were examined in a recent small study involving 11 young men published in the journal Experimental Physiology. After six hours of sitting, the vasculature function in one of the leg’s main arteries was reduced by more than 50%, but was restored after 10 minutes of walking, said Jaume Padilla, an assistant professor in the department of nutrition and exercise physiology at the University of Missouri in Columbia and senior author of the study.
“More research is needed to determine if reduced vascular function with prolonged sitting leads to long-term vascular complications,” said Dr. Padilla.
Scientists also are studying how to induce people to sit less. An article published online in the journal Health Psychology Review last week reviewed various studies looking at 38 possible interventions to get people out of their chairs. Among those that worked: educating people about the benefits of less sitting time; restructuring work environments, such as adding standing or adjustable desks; setting goals for the amount of time spent sitting; recording sitting times; and creating cues or alerts for people when they need to stand, said Benjamin Gardner, senior lecturer at the Institute of Psychiatry, Psychology & Neuroscience at King’s College in London and first author of the article.
The majority of interventions that didn’t work were aimed at getting people to do more physical activity, Dr. Gardner said. “We need interventions that are designed specifically to break up sitting as well as interventions that try to get people to move about more,” he said.
Michael Jensen, a professor of medicine at the Mayo Clinic in Rochester, Minn., who specializes in obesity and diabetes, uses various ways to reduce daily sitting time that he also recommends to his patients. When he has meetings with just one or two people he finds a place where they can walk together instead of sitting. And he tells his patients who are parents to use their children’s athletic events as a time to be on their feet. “There’s no reason you have to sit and watch those games,” Dr. Jensen said.
Originally published in The Wall Street Journal, September 28, 2015.