Few people interested in fitness are unfamiliar with the concept of high-intensity interval training, or HIIT, which involves very short, very strenuous bursts of exercise interspersed with periods of rest. But many people are intimidated to try such workouts.
As my colleague Tara Parker-Pope reported recently, using a heart-rate monitor helped her overcome her fear of HIIT. But a new study shows that for many, just trying an HIIT workout for the first time may be a critical step in including high-intensity training as part of your everyday routine.
The study undercuts some widespread assumptions about the psychological effects of intense exercise and also indicates that short, hard workouts could be a practical alternative to other forms of exercise in part because we do not hate them.
HIIT has gained considerable attention in recent years, thanks to experiments showing that even a few minutes a week of strenuous intervals improve aerobic fitness and other aspects of health as much as hours of jogging or moderate bicycle riding.
But some scientists have argued that the potential physical benefits from intense training will be illusory if people do not complete the workouts.
Their concerns are based on past research showing that if exercise is intense, most people report not liking it.
But those studies primarily examined nonstop intense exercise, such as continuous, hard bicycling or running, and not interval training, which interrupts the strenuous exertion with rest periods.
So for the new study, which was published in May in Medicine & Science in Sports & Exercise, researchers from the University of British Columbia in Kelowna and McMaster University in Hamilton, Ontario, decided to ask a group of ordinary people to try a variety of workouts and see if they liked them.
The researchers began by gathering 30 men and women who were inactive in general and had not tried interval training before.
They brought them into the lab, tested their fitness and familiarized them with different measures of how they felt during exercise. One of these asked them to estimate the relative intensity of a workout on a scale of 1 to 10, while another required rating the pleasantness (if any) of a workout on a similar numeric scale.
They then had each volunteer complete three workouts on separate days. During one, the participants rode a stationary bicycle for 45 minutes at a steady, moderate pace.
During another, they tried standard high-intensity interval training, riding hard for one minute, resting for a minute, and repeating the sequence 10 times.
For the last workout, they were introduced to super-high-intensity training, consisting of pedaling as hard as they possibly could for 30 seconds three times, with two minutes of rest between each grunting bout of all-out pedaling.
Capitalizing on the rest periods between intervals, the researchers repeatedly asked the men and women to assess how they felt during their exertions and also, afterward, to rank each workout according to which had been most and least enjoyable.
Then, in perhaps the most important element of the study, the scientists waved farewell to their volunteers, but asked them to keep logs of their physical activities for a month, to see if people would choose to continue any of the workouts on their own.
To no one’s surprise, when the scientists tallied results, the cyclists proved to have unanimously reported less fatigue and more happiness during the moderate pedaling, especially if the researchers checked in near the end of either of the sessions of tiring intervals.
But afterward, with the exercise behind them, people’s opinions shifted and almost all of the volunteers decided that, in retrospect, they had found the workouts almost equally enjoyable and would in fact rank the standard, high-intensity interval training as the most pleasant.
About 80 percent of them also tried at least one session of interval training in the month after the experiment, although they completed more moderate workouts in that time.
These findings indicate that intervals could be less onerous than many of us probably expect, says Matthew Stork, a doctoral student at the University of British Columbia who led the study.
The study also reinforces the fundamental message about intervals, which is that they are hard and physically difficult, which some people will never enjoy.
Still, Stork says, if you are pressed for time, brief interval sessions might offer a viable way to fit exercise into your life.
“And you can’t know whether you will enjoy them or not,” he says, “until you try them.”