Some past research had suggested the answer is no. A 2016 study involving more than a million people found, instead, that men and women needed to exercise moderately for about 60 to 75 minutes a day in order to diminish the undesirable effects of sitting.
That study, though, like most similar, earlier research, asked people to remember how much they had moved or sat, which can be problematic. We tend to be unreliable narrators of our lives, overestimating physical activity and underestimating how much we sit. But if large numbers of people misremember this way, the paradoxical result is that exercise looks less potent than it is, since the studies’ “active” people appear to have needed plenty of exercise to gain health benefits, when the objective amount of exercise they actually completed was less, and this smaller amount produced the gains.
So, for the new study, which was published last week in a special issue of the British Journal of Sports Medicine devoted to the World Health Organization’s updated physical activity guidelines and related research, many of the authors of the 2016 review decided to, in effect, repeat that earlier research and analysis, but, this time, use data from people who had worn activity monitors to objectively track how much they moved and sat.
The scientists wound up gathering results from nine recent studies in which almost 50,000 men and women wore accelerometers. These studies’ volunteers were middle-aged or older and lived in Europe or the United States. Combining and collating the nine studies’ data, the scientists found that most of the volunteers sat a lot, averaging close to 10 hours a day, and many barely moved, exercising moderately, usually by walking, for as little as two or three minutes a day.
The researchers then checked death registries for about a decade after people had joined their respective studies and started comparing lifestyles and life spans. Dividing people into thirds, based on how much they moved and sat, the researchers found, to no one’s surprise, that being extremely sedentary was hazardous, with people in the top third for sitting and bottom third for activity having about 260 percent more likelihood of premature death than the men and women who moved the most and sat the least. (The researchers controlled for smoking, body mass and other factors that might have influenced the results.)