Set Your Exercise Goals High, but Not Too High

They began by recruiting 20 overweight, adult men and women who were, at the start, inactive but healthy enough to walk. They outfitted the volunteers with activity trackers and asked them to continue their normal lives for two weeks, while the researchers established their baseline step counts, which turned out to average about 5,000 steps a day.

Then the researchers had the volunteers download a phone app that sent them individualized step-count goals every day. The goals ranged, at random, from the same number of steps someone took at baseline up to 2.6 times as many. So, one day, participants might be aiming for their normal 5,000 steps and, the next day, 13,000.

The experiment continued for 80 days, after which researchers compared people’s daily goals, achievements and resulting, overall activity levels. And they found that people clearly walked more on days when they were asked to walk more; whenever goals exceeded people’s baseline step counts, they were more active, even if the goals were quite ambitious.

But few people achieved the highest step-count goals, often falling far short and, in general, walking little more than — or even less — than on days when the goals were more moderate. In essence, goals that people almost reached seemed the most effective at getting and keeping them moving.

Of course, this was a small, short-term study and did not directly ask about people’s exercise motivations or whether they felt demoralized by failing to finish those 13,000 steps. It also looked at walking, which is not everyone’s preferred exercise, and steps, which some people may not have the desire or technological wherewithal to count. (Almost all mobile phones contain accelerometers, which will count steps for you, or you can purchase inexpensive pedometers.)

But the results contain useful advice for anyone hoping to be more active this year. “Set precise, dynamic goals that are not too easy but realistic,” Dr. Chevance says. Maybe check the activity app on your phone for the past month, he says, to see how much you already walk and “add 10 percent” as this week’s goal, a plan that would have you increasing by about 500 steps a day if your current life resembles that of the study volunteers.

Update this goal “at least every week,” he says, upping steps — or time or distance — once you easily exceed your target and dropping the bar a bit if you remain far below. “If you are close,” he says, with the goal still a little distant, “you are on the right track.”