Please Don't "HIIT" the Trainer!

No, that's not a typo: "HIIT" is an acronym that stands for High Intensity Interval Training, and it seems to be one of the hottest trends in fitness. Indeed, HIIT made the top of the list in the American College of Sports Medicine's annual survey of fitness trends.

You may have heard of HIIT as the "newest," "best," "most amazingest," "magic-est" way to lose weight or achieve some other goal. Is it? Well, yes and no.

HIIT is basically just a new trendy acronym for a form of training people have been doing for a long, long time. Most of the time, however, the only people doing it were competitive athletes trying to run, bike, and/or swim faster in races. In short, this type of training trains your body to tolerate a harder effort for a longer period of time by putting a higher stress on it for a relatively short length of time (compared to, say, the length of time you will be racing), then resting briefly, then stressing it again, and so on.

A typical session for a runner might be something like this: 1 mile easy, 1/4-mile faster, 1/4-mile easy, 1/4-mile faster, 1/4-mile easy, then finish with 1 mile easy. This workout might typically be done in 30 minutes. HIIT has grown in popularity because most people have a limited amount of time available to exercise, so they want to accomplish more in that same time period. That is, they can't extend their slower running/biking/swimming regimen to a longer workout because of work or other commitments, so increasing intensity is the logical option.

Will this cause you to lose that 15 pounds in three days, as some would have you think? No, but there are benefits compared to just jogging slowly for the same 30 minutes. And it's not necessarily as complicated as you might think. Weight loss or weight management is simply arithmetic. When you exercise harder, you burn more calories. If you run 3 miles in 30 minutes and I run 4 miles in 30 minutes and we start off at about the same weight, I will burn more calories. So, of course, if you do this "HIIT" workout, which involves some more intense running, you'll burn more calories than if you simply jogged slowly for the same 30 minutes. Therefore (assuming you don't compensate by eating more calories), you will be more likely to lose weight doing this kind of workout.

What about other issues? Could HIIT be bad for you?

Technically, yes. If your body isn't ready to exercise with more intensity and if you don't warm up properly, you could certainly injure yourself. If you run with poor form (say, heel-striking instead of mid-foot striking), you could magnify the bad stresses on your joints during a workout that is more intense and increase the likelihood of pain or injury. If you don't have a decent base of fitness, you could conceivably put too much strain on your heart trying to go too fast - that is definitely not something you want to do.

Should you try HIIT? Personally, I like to try different things for myself, so if I weren't already doing this as part of my usual training regimen (which I've been doing for decades), I would definitely try it. I did introduce it to one of my Be The Runner clients a few months ago, and she tells me she feels stronger and thinks she may be losing weight (she hasn't tracked it carefully enough to know). For her, she uses an elliptical machine, so we mapped out a workout that incorporates a few higher intensity blocks of a few minutes within the same 30-minute time frame that she's been doing for a long time. Presto, she's doing HIIT!

Are you going to try it the next time you "HIIT" the gym?