Now, to tease out the links between how much people moved and how long they lived, the researchers divided the 36,383 men and women into four categories, based on how often and intensely they moved. People who sat for long hours and almost never formally exercised constituted the least-active group. Those who moved about for approximately an hour more each day, even if their activities were untaxing, made up the second-least-active group, and so on.
The researchers next compared activity levels and mortality and found, to no one’s surprise, that the men and women who were the most active were the least likely to have died. That group’s risk of premature death was about 60 percent lower than for the men and women in the most-sedentary group.
More unexpected, people in the second-least-active group also were significantly less likely to have died than those in the least-active group, even though their activities consisted primarily of moseying, housecleaning, cooking or gardening.
Over all, the researchers found, someone’s chances of dying prematurely continued to drop the more he or she moved, up to a plateau at about 25 minutes per day of moderate exercise, such as brisk walking, or 300 minutes a day of light, gentle activity. Beyond that point, people did not gain additional longevity benefits, although their risks of premature death did not rise either.
The relationship between moving more and living longer remained strong even when the researchers controlled for body mass, smoking, diets and other factors and excluded data from anyone who had died during the first two years of the follow-up period, since they might have been inactive because of an underlying illness.
Of course, this was an observational study, and does not show that being active causes us to live longer, only that the two are associated. It also looked almost exclusively at Caucasian adults.
But the findings are encouraging, says Ulf Ekelund, a professor at the Norwegian School of Sport Sciences in Oslo, Norway, who led the new study. They suggest that “all activity counts” in terms of reducing our risk of dying early, he says.