When you think of high-intensity interval training, walking probably isn’t the first thing that comes to mind. After all, HIIT workouts are usually associated with multiple repetitions of high-energy exercises like burpees, sprinting and pushups, which isn’t in the same league as going for a walk around the neighbourhood. Still, HIIT workouts aren’t defined by the type of exercise, but by how the workout is structured.
HIIT involves repeated short bouts of high-intensity exercise interspersed with bouts of active recovery. Touted for its efficiency, it boasts improvements in health and fitness equal to or greater than traditional steady-state workouts, but in less time. The downside is that for HIIT to be effective, the work intervals need to be performed at close to maximum effort, which isn’t for everyone.
On the other end of the spectrum is a walking workout, which is typically performed at a moderate intensity sustained throughout the workout. Moving at a comfortable energetic pace is an easier and more enjoyable form of exercise for a large majority of the population. But it takes a lot of walking to match the physiological benefits of a HIIT session.
Given the differences between the two workouts, the folks who love HIIT aren’t the same ones you see briskly walking around the neighbourhood in their workout wear. But there’s one element of a HIIT workout that most exercisers — even those who prefer something a little less sweat-inducing — seem to enjoy: the variety that comes from mixing it up with intervals.
With that in mind, a team of researchers from the U.K. decided to compare an interval walking workout with a time-matched steady-state walk to see if it was an effective option for anyone willing to take their walking workout up a notch.
“We hypothesized that interval walking would elicit meaningfully greater energy expenditure than continuous walking and that participants would report interval walking to be meaningfully more enjoyable than continuous walking,” stated the researchers.
To test their hypothesis, they recruited 16 healthy but “insufficiently active” adults (13 women and three men) who weren’t performing the recommended 150 minutes of moderate-intensity exercise a week and asked them to hop on a treadmill and give both types of workout a try.
The continuous workout lasted 30 minutes, with the walkers maintaining an intensity equivalent to 65 to 70 per cent of their maximum heart rate (considered moderate intensity). The interval workout also required 30 minutes on the treadmill, but this time the walkers performed intervals of three minutes at 80 per cent of maximum heart rate (vigorous intensity) interspersed with two minutes of lower-intensity walking (50 per cent of maximum heart rate). The work/recovery intervals were repeated three times.
The difference in results verified the researchers’ hypothesis: interval walking burned more calories than the continuous steady-state workout. As for enjoyment, 75 per cent of the walkers preferred the interval workout over maintaining a consistent pace for the full 30 minutes.
To get an idea of how much more efficient interval workouts are, the researchers provided an example that might prove enticing to the average fitness walker who maintains the same brisk pace from start to finish.
“Recommended weekly activity energy expenditure for reducing rates of cardiovascular disease and premature mortality is 1,000 calories a week,” said the team. “For participants in the current study to achieve this caloric expenditure, they would need to perform continuous walking for 217 minutes a week (about 7 x 30-minute workouts); however, they would only have to perform interval walking for 184 minutes per week (approximately 6 x 30-minute workouts) — an estimated 15 per cent reduction in exercise time.”
What does this mean for the average walker? It might be time to mix it up, especially if your walking workouts have started to get a little stale. Picking up the pace will get your heart racing and your muscles pumping, which is made easier knowing that every work interval is followed by a period of recovery.
If you’re worried you won’t be able to maintain a brisk pace for the same length of interval (three minutes) as the walkers in the U.K. study, don’t hesitate to change it up. Try 60 seconds of fast walking followed by 60 seconds at a more comfortable pace, slowly adding time to each of the intervals until you can maintain a good clip for the full three minutes. Or try a 1:2 work-to-rest ratio — one minute of work, followed by two minutes of recovery.
There is one element of a HIIT workout that isn’t modifiable: to be effective, the work interval needs to be performed at a minimum of 80 per cent of your maximum effort, which should feel strenuous. So go ahead and pick up the pace, even if it’s only for a few minutes at a time. Your health and fitness will thank you.