When I suggest to clients that we should do a few intervals during a session, the ones who know what that entails look like they’re already in pain. The ones who don’t are in for a rude awakening… (He, he, he *rubbing hands together*. Yes, I have a sadistic streak:)) Interval training is also known as HIIT (High Intensity Interval Training). I’ll use IT and HIIT interchangeably in this article.

Some people believe intervals are only for runners, but they’re wrong. It is true that interval training has its origin among runners. Alternating between slow and fast speeds to get faster and more fit is an idea that’s been around since the 1800s, though it became far more advanced as of the 1930s. The great thing is that you can incorporate this metabolically effective exercise approach to most workouts, including strength-training. And you should, if you desire maximum results.

BENEFITS OF INTERVAL TRAINING:

It’s time-efficient. Who wants to spend hours a day on their workouts? Not me, that’s for sure. Interval training can give you the same calorie burn in half the time of a regular workout. Why spend 45-60 min when you can reap the same benefits in 20 or 30? You’ll also get a better after burn from HIIT, meaning you’ll burn more calories in the hours following your workout than you normally would. According to National Library of Medicine, the harder you push yourself, the longer it’ll take for your metabolism to return to a normal, resting state. This gets you results faster, leading you to actually want to train/run/get fit. You will no longer dread your workouts.

It maintains muscle mass. Unlike steady-state training, IT preserves your muscle mass and might even add more. (Read more about this here.)Think that pudgy guy or gal using the elliptical machine for an hour every night, yet never changing their body. He or she is doing a favorite steady-state exercise. Even if they break a sweat, it won’t yield the results of a shorter HIIT session. A big reason for that is because SS cardio eats your muscle. Intervals do the opposite, producing muscle-building hormones. Still, in terms of muscle growth, straight-forward strength-training is most effective. Of course, mix the two and you’ll have amazing results in no time…

It makes you smarter. According to NASM’s Pete McCall, IT will improve your brain capacity: “HIIT has been shown to have a more significant impact on elevating levels of BDNF when compared to moderate-intensity, steady-state exercise.” BDNF–Brain-derived Neurotrophic Factor–is a protein that promotes the production of new brain cells. Insufficient levels of BDNF are associated with depression, Alzheimer’s disease, bipolar disorder and schizophrenia.

It boasts your endurance and makes you healthier. After getting through a few sessions of torturous IT, you’ll notice how it’s easier to…do just about anything. You won’t get out of breath as easily and you’ll be able to do your regular run/spinning class faster and harder. It’s like a good vicious circle; you just get fitter and fitter. Your blood sugar and insulin resistance will improve more than with regular cardio, making this strenuous workout style ideal for Type 2 Diabetes prone individuals. (Read about the health benefits here.)

It’ll make you feel AMAZING. As painful as it is pushing yourself to the max–because that’s what you must do during the intervals–nothing beats how great you’ll feel afterwards (after a balanced meal and a shower). You’ll be flying over the floors and smiling at everyone. Like you’re high on drugs yet you’re as healthy as can be. (Yes, I have tried a few of those in my younger days, so I know exactly what I’m talking about here.) Because maximal effort obviously varies from person to person, look at it this way: on a scale from 1-10, 10 being the hardest, you want to reach at least a 7 maximal effort for you. It’s good to push harder, reaching a 9 or even 10, but it’s not necessary. When I’m not in the mood, I usually go for an 8 max intensity, just to give you an idea.

You’ll become lean. Because HIIT workouts preserve muscle mass and speed up fat burning, you’re more likely to attain that toned and defined look most people want. (For more about this, check out this article.) You’re especially likely to achieve this look if you include strength-training with your intervals. I wrote an article about High Intensity Resistance Training that includes a sample workout. Go here to do the workout.

HOW TO DO IT: You have lots of options for your IT. You don’t even need any equipment. Here’s an example of a short HIIT workout: do 15 burpees, walk it off for one minute and repeat the sequence 3 or four more times. Basically, you push yourself to the max, spiking your heart rate during the interval. During the break, you want to get it back to low again to recover. When you feel recovered, you do another interval. The length and intensity of both the intervals and the recovery periods can vary as much as you want, though having a set time goal might make it easier for you. I like to do 30-60 seconds sprints on the treadmill, for example, when I feel motivated, or while doing full-body weight training sessions. (Check out my sample workout.) Mainly, I prefer doing IT in biking classes or using the rowing machine.

WHAT’S THE CATCH? Pushing yourself to the max is not easy. Not many people can do it on their own. It can be very painful. To be honest, I felt like I was about to die the first five or so times I did it. I became nauseous. I’m good at pushing myself, but I often feel I need someone cracking the whip over my head to go all out. Taking biking classes where you compete with the other participants to achieve your max is a great approach. The club I work for, Equinox, has excellent classes that make me crawl out of studio drenched in sweat. I’m completely spent. You may find other types of classes do the same for you.

To be safe, always check with your doctor whether your heart can handle HIIT workouts before you start doing them. They’re extremely efficient, but also stressful on the heart. Don’t do them all the time, but more like every other time you exercise. It’s fine to do steady-state cardio in between to give your body a break. Good luck!