The sweet spot for physical activity and longevity seemed to arrive at about 35 minutes a day of brisk walking or other moderate activities.
Walking for at least 11 minutes a day could lessen the undesirable health consequences of sitting for hours and hours, according to a helpful new study of the ways in which both inactivity and exercise influence how long we live. The study, which relied on objective data from tens of thousands of people about how they spent their days, found that those who were the most sedentary faced a high risk of dying young, but if people got up and moved, they slashed that threat substantially, even if they did not move much.
For most of us, sitting for prolonged periods of time is common, especially now, as we face the dual challenges of Covid-related restrictions and the shortening, chilly days of winter. Recent surveys of people’s behavior since the start of the pandemic indicate that a majority of us are exercising less and sitting more than we were a year ago.
Not surprisingly, there could be long-term health consequences from this physical quietude. Multiple past epidemiological studies show links between sitting and mortality. In general, in these studies, couchbound people are far more likely to die prematurely than active people are.
But how active an active person should be if he or she hopes to mitigate the downsides of sitting has remained unclear. If you sit for eight hours at work, for instance, then stroll for half an hour in the evening — meaning you comply with the standard exercise recommendation of about 30 minutes of exercise most days — is that enough movement to undo most of the health risks of too much 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.