High-intensity interval training (HIIT) can be done in a measured way that provides big exercise benefits without big injury risks.
NICOLE Lindemann, a business owner, wife and mum, speaks the truth: “Basically, I’m like everyone else in the world – we’re not getting any younger or any better in shape.”
So, resolutionaries, time to bust a move. But how, exactly?
The 38-year-old Lindemann didn’t know that the American College of Sports Medicine (ACSM) named “high-intensity interval training” as the top global trend for 2014 when she signed up for just such an exercise class a few weeks ago.
That’s HIIT, or just say “hit”.
If the term brings anything to mind, it’s probably the image of those cabals of impossibly fit-looking folks sweating it out on TV commercials. They’re hawking such hard-core workouts as CrossFit and P90X, which are types of high-intensity training.
No doubt the popularity of these well-marketed programmes shot HIIT to the top of the ACSM’s trend watch, accompanied with warnings from fitness experts that extreme regimens can be injury-inducing and “aren’t for everybody”.
There’s actually nothing new about intense interval training, which goes back at least to the 1930s and Fartlek, the famed Swedish programme. And it can be done in a measured way that provides big exercise benefits without big injury risks, says Kri Chay, a certified trainer and owner of Urban HIIT FITT in Lee’s Summit, Missouri, United States.
The latest science backs him up on this. The central idea couldn’t be simpler: Go hard. Then go easier or rest. Repeat.
“It’s the notion of alternating relatively intense exercise with periods of recovery,” said Dr Martin Gibala, a kinesiology professor at McMaster University in Hamilton, Ontario, Canada, who has studied the topic for 10 years. “And it can be properly scaled for different levels of fitness.”
The benefits are impressive, Dr Gibala said, and they can be achieved in about half the time of continuous moderate-intensity exercise.
That’s a big deal, because lack of time continues to be the No. 1 barrier people cite to getting regular exercise, he says.
Lindemann is a newbie in Chay’s first-of-the-year, six-week session. She wasn’t interested in becoming an ultra-exerciser. She’s busy enough with her seven-year-old daughter and her business, Kidz First Therapy, which provides occupational therapy for children with special needs.
But she does want to be healthier, in better shape, and to look better in her clothes.
At the start of a recent class, Chay pointed to a dry-erase board with the session’s 10 exercises, the set on the left for newbies and on the right for veterans.
Participants – 14 women and four men with a range of body shapes – were to hit each exercise for 40 seconds, with a 20-second break to move to the next station.
With music blasting, they were to cycle through the 10-exercise regimen three times. A buzzer marked the end of each 40-second interval and a bell sounded for the start of the next.
“Go hard, baby,” Chay yelled.
There were dumbbells, kettlebells, hanging rings and other equipment at the stations, set up for various types of lifting and bodyweight, or calisthenic-style, exercises.
Chay circulated, helping with proper form, and sometimes offering modifications of some exercises. A woman with a bad ankle needed an alternative at one of the stations.
“I like to incorporate upper and lower body, push and pull,” he said. “They choose their level, and I modify the programme if someone needs it, even on the fly, in the middle of class.”
Lindemann likes the variety, and she thinks there’s a psychic advantage to the intervals.
“It makes me push harder because I know the duration isn’t that long,” she said.
In fact, that “short-term goal” of the intense interval has been shown to be a plus for exercisers, not to mention that the on-off method, even repeated, helps to fight boredom, said Dr Micah Zuhl, a clinical assistant professor at Central Michigan University’s School of Health Sciences, US.
Interval training is being used in rehabilitation clinics, he said, even with cardiac patients, which was unheard of just a few years ago.
Dr Zuhl said intervals can be adapted to many types of full-body workouts, with or without equipment, and is used in swimming, biking and running, including on cardio machines.
“What’s really hot right now is sprint training,” he said, interspersing sprints, rests and jogs of various lengths.
There are no set guidelines on interval length, Dr Zuhl said, although research is showing the best benefits when the high-intensity portion is set at 30 seconds to two minutes. In studies, the “go easier” or rest period is often twice as long. So, for example, 30 seconds of high-intensity effort would be followed by one minute of recovery.
How intense should the high-intensity be?
“There’s no free lunch,” Dr Gibala said. “If the time-efficiency aspect is attractive to you, then you’re going to have to go hard with these intervals.”
One approach, especially when starting out, he said, is to “get out of your comfort zone” for the go-hard interval. If you’re running outdoors, for instance, resolve to pick up the pace from one streetlight pole to the next, then back off.
As always, talk to your doctor before trying a new exercise programme. A certified personal trainer can help you determine proper intensity, Dr Gibala said.
Heart-rate targets are a more exact way to determine exertion, but those are also variable from person to person, he said.
First, figure the average maximum heart rate for someone your age – subtract your age from 220. Then shoot for a heart rate about 85% of that number during the high-intense intervals.
If you’re 40, the average maximum is 180, so the target would be 153 beats per minute.
Dr Gibala said many of his studies have used exercise bikes with a protocol of one minute of intense effort, followed by one minute of recovery, repeated 10 times per session. Participants performed three of these 20-minute sessions over a week.
“We’ve shown benefits for people with type 2 diabetes in just two weeks,” said he, noting that this was a total commitment of one hour a week. “Their blood-sugar levels are markedly reduced.”
Dr Mike Bracko, an exercise physiologist and ACSM programme planner, said it isn’t well-understood why HIIT produces such time-efficient results.
Of course, the exerciser is working harder during the intense bursts than in any similar periods of continuous exercise.
But the physiological benefits might also be a result of both ramping up and down the intensity, he said, and from the “after-burn”. It’s known that people burn calories longer after interval training than after continuous or endurance training.
Some advocates are so sold on interval training they recommend jettisoning continuous styles of exercise. But Dr Gibala and others say that’s unnecessary.
They suggest limiting HIIT sessions to two or three a week, alternating on other days with continuous or steady-state exercising, including strength training and cardio.
At the end of his HIIT class recently, during post-workout stretching, Chay talked to members, not about the workout or its intensity, but about ... food.
Chay requires class members to record what they eat and drink in food journals, which he monitors. They must bring their journals to class, or else.
“Last night somebody forgot their food journal, and we all had to run outside,” Lindemann said.
The workouts won’t matter, Chay told participants, if eating and drinking aren’t under control.
“You can’t out-train a bad diet.”
Go hard, go easy
With high-intensity interval training, the workout possibilities are nearly endless. Here are three samples of how to incorporate HIIT into an exercise session. The times and distances are only suggestions and can be varied for an individual’s conditioning level.
The first two are from Kelly Garroutte, an Overland Park personal trainer with a master’s in exercise physiology. These simple workouts use full-body exercises – burpees and mountain climbers – that spike the heart rate.
Less-intense exercises, focused on different muscle groups, are used for the recovery periods.
For equipment, the first requires a cable rowing machine, the second a set of dumbbells. (A quick online search will explain how to perform burpees, mountain climbers, dumbbell curls and dumbbell lateral lifts.)
The third sample is from Dr Zuhl. It is a running workout with sprints and a jog.
1. Burpees: 30 seconds
2. Seated cable rows: 60 seconds
Repeat three times.
1. Dumbbell curl: 30 seconds
2. Dumbbell lateral lift: 30 seconds
3. Mountain climbers: 30 seconds
Repeat three times.
1. Sprint: 30m
2. Rest: One to three minutes
Repeat eight to 12 times.
3. Light jog: 5km to 10km. – The Kansas City Star/McClatchy-Tribune Information Services