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.
There’s actually nothing new about intense interval training, which goes back at least to the 1930s and Fartlek, the famed Swedish program. 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.
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 Martin Gibala, a kinesiology professor at McMaster University in Hamilton, Ontario, who has studied the topic for 10 years. “And it can be properly scaled for different levels of fitness.”
The benefits are impressive, 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.
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.
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.
“I like to incorporate upper and lower body, push and pull,” Chay said. “They choose their level, and I modify the program if someone needs it, even on the fly, in the middle of class.”
The 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 Micah Zuhl, a clinical assistant professor at Central Michigan University’s School of Health Sciences.
Interval training is being used in rehabilitation clinics, he said, even with cardiac patients, which was unheard of just a few years ago.
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.
There are no set guidelines on interval length, 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.
One approach, especially when starting out, Gibala 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 program. A certified personal trainer can help you determine proper intensity, Gibala said.
Heart-rate targets are a more exact way to determine exertion, but those also are 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 percent 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.
“We’ve shown benefits for people with Type 2 diabetes in just two weeks,” said Gibala, noting that this was a total commitment of one hour a week. “Their blood-sugar levels are markedly reduced.”
Mike Bracko, an exercise physiologist and ACSM program planner, said said 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.
Gibala and others 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.
Go hard, go easy
With high-intensity interval training, the workout possibilities are nearly endless. Here are two 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.
1. Dumbbell curl: 30 seconds
2. Dumbbell lateral lift: 30 seconds
3. Mountain climbers: 30 seconds Repeat 3 times.
1. Sprint: about 100 feet.
2. Rest: 1 to 3 minutes
Repeat 8 to 12 times
3. Light jog: 3 to 6 miles.
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