Supervised lab sessions are not a good reflection of real-life exercise, however. So, as a final step in the study, the researchers asked the volunteers to go home and work out on their own for a month, keeping exercise logs, then return to the lab to talk at length with the researchers again.
This month of do-it-yourself workouts proved to be revealing. Almost everyone remained active, with most completing frequent, moderate exercise sessions, like the 45-minute bike rides at the lab. But many also threaded some sort of interval training into their weekly workouts, although few of these sessions replicated the structured intervals from the lab. Instead, people tended to sprint up and down stairs or grunted through some quick burpees and other body weight exercises.
Most interesting, during their subsequent, prolonged interviews with the researchers, the volunteers who interval trained on their own said they felt more engaged and motivated during those workouts than in the longer, continuous-intensity sessions, even when the intervals were physically draining.
The upshot of the study data would seem to be that many of us might want to consider H.I.I.T., if we have not already, says Matthew Stork, a postdoctoral fellow at the University of British Columbia, who led the new study. We might surprise ourselves by liking the workouts.
But, he points out, some volunteers continued to prefer the familiar, less-intense exercise, and almost everyone completed more of those sessions than of intervals.
“What the data really show is that there is no one-size-fits-all way to work out,” Dr. Stork says. The best exercise will be the one each of us ultimately relishes most, he says. It may require some experimentation, though, for us to settle on our particular, preferred workouts.
Of course, this study involved healthy young adults and followed them for a month. Whether people who are older or have health concerns will respond similarly to intervals and whether anyone will stick to their chosen workouts for more than four weeks remain uncertain. Also, people who have not exercised in some time should generally consult a physician before tackling a new exercise routine.