However, supervised lab sessions do not reflect the actual exercises. As the final step in the study, the researchers asked the volunteers to go home for a month and exercise on their own, keep exercise logs, and then return to the lab to speak with the researchers again at length.
This month of do-it-yourself training turned out to be enlightening. Almost all of them stayed active, with most doing frequent, moderate workouts, such as the 45-minute lab bike rides. However, many also incorporated some form 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 grunt through a few quick burpees and other bodyweight exercises.
Most interestingly, the volunteers who trained at intervals felt more engaged and motivated during their subsequent, longer interviews with the researchers during these training sessions than during the longer, continuous intensity sessions, even when the intervals were physically demanding.
The result of the study data appears to be that many of us are H.I.I.T. would like to consider if we haven't already, says Matthew Stork, a postdoctoral fellow at the University of British Columbia who led the new study. We might surprise ourselves if we like the workouts.
However, he notes that some volunteers continued to prefer the familiar, less intense exercise, and almost everyone did more of these sessions as intervals.
"What the data really shows is that there is no single way to exercise," says Dr. Stork. The best exercise will be the one that each of us ultimately enjoys the most, he says. However, it may take some experimentation to settle on our specific, preferred workouts.
Of course, this study included healthy young adults and followed them up for a month. It remains uncertain whether elderly people or health concerns will react in a similar way to intervals and whether someone will stick to their chosen training for more than four weeks. In addition, people who have not exercised in a while should generally consult a doctor before starting a new exercise routine.