HIIT - High Intensity Interval Training - FAQ

What is “HIIT” or High Intensity Interval Training?

The generally accepted definition is: performing an exercise at a rate that’s near your maximum exertion for short time intervals, alternated with intervals of slower paced recovery activity, or with rest periods.

An easy way to measure the difference between “near maximum exertion” and “recovery” is to rate your exertion on a scale of 1 to 10, with 1 being I can do this all day, to 10 being OMG I’m going to pass out in 15 seconds. The high intensity portion of your activity should be around an exertion level of 8 or 9, and the recovery/rest portion should be around 5 or 6.

Just like steady state (traditional) cardio, you can do HIIT with any activity that will get your heart rate/exertion level up. Running, swimming, jumping/skipping rope, cycling, elliptical, burpees, digging ditches… if you can do it intensely enough to get to 8 or 9 on the exertion scale, then it will work for HIIT.

Why HIIT?

Basically, what researchers have found is that steady cardio burns the same number or more calories during the activity as HIIT, but HIIT continues to burn more calories even after you’re done. While steady state cardio might burn more fat calories, when it comes to losing weight, it doesn’t matter what kind of calories you burn, only the total number of calories.

Furthermore, HIIT increases fat oxidation (fat burning) in muscle fibers, and all the research I found showed that people who did HIIT on a regular basis had lower body fat percentages than those who did steady state cardio.

Here’s a really good summary of the research: Fit with HIIT.

How long should a HIIT session be?

So how much HIIT equals steady state cardio? That’s a bit more difficult to figure out.

A recent study had one group do 40 minutes for a total session, alternating one minute of high intensity with one minute of rest; and a second group did 90-120 minutes of steady state cardio. When the researchers compared results, they found that people who did 80 minutes of high intensity cardio (not including the rest minutes) showed about the same improvements as those who did 825 minutes of steady state cardio. I doubt this means that you only have to do 10% of the steady state cardio time you have done before! Most of what I read recommended HIIT sessions to be about half the time of your steady state cardio, working up to a HIIT session between 15 and 30 minutes long (depending on your fitness level, goals, and any sport-specific HIIT you’re doing). Reference: Go ahead, HIIT yourself

Who should do HIIT and how?

HIIT is not recommended for novice exercises. It puts a high demand on your body, and if you’re not used to exercising, you can increase the possibility of getting injured. If you have high blood pressure, heart disease, or joint problems like arthritis, talk to your doctor before you start.

Here are some good tips:

-- ALWAYS warm up completely before you begin, preferably with the same activity you’re going to do for HIIT. (Walk and run slowly before you begin sprinting; cycle slowly before you start cycling hard, etc.) ALWAYS cool down slowly and stretch when you’re done!

-- Be realistic with what you attempt, and keep in mind how you might feel tomorrow. That high intensity exercise you did today might feel okay today, but give you major DOMS tomorrow, and affect your workout plans.

-- Start slowly. Alternate two minutes higher intensity with two minutes of lower intensity. Assess how you did, and see how you feel the next day or two.

-- Begin by doing HIIT once or twice a week, and gradually work your way up to doing it more often. Keep in mind your goals; if you’re working toward doing a marathon or triathlon, you still need to do longer steady state cardio tailored to those sports.

-- Be careful about overtraining. You can overtrain with HIIT just as you can with any other exercise activity. If you feel like you’re not improving, or your performance is going backwards, you just feel generally ‘tired’, or you have continuing aches and pains, then ease off on how often you do HIIT.

-- To get better, increase intensity OR duration, but not both at the same time!

What’s a good HIIT routine?

If you’re just starting doing any sort of cardio, don’t attempt HIIT yet. Work up so you can do your cardio of choice for 20 minutes.

When you’re just starting HIIT, it’s best to go with 2 minutes of high intensity, alternated with 2 minutes of recovery (lower intensity or rest), for 10-20 minutes total.

ALWAYS WARM UP FIRST AND COOL DOWN AND STRETCH AFTER!

For example:

Run fast 2 minutes
Run slow or walk 2 minutes
Repeat until you reach 10-20 minutes total

Cycle fast 2 minutes
Cycle slow 2 minutes
Repeat until you reach 10-20 minutes total

As you get used to doing HIIT, reduce the intervals to 1 minute each.

You can also do pyramids, for example:

Cardio fast 1 minute
Cardio slow 2 minutes
Cardio fast 1 minute
Cardio slow 1 minute 30 seconds
Cardio fast 1 minute
Cardio slow 1 minute
Cardio fast 1 minute
Cardio slow 30 seconds
Cardio fast 1 minute
Cardio slow 1 minute
Cardio fast 1 minute
Cardio slow 1 minute 30 seconds
Cardio fast 1 minute
Cardio slow 2 minutes
Cardio fast 1 minute

You can also substitute distance instead of time; instead of 1 minute, do 200 meters (or 300 meters, or “from here to that house and back again”).

You don't need an "expert" to make up a HIIT routine for you. Take your favorite cardio activity (or the cardio you hate the least...) and alternate the intensity every one or two minutes. You can even mix up the type of cardio activity; do one interval of burpees, recovery interval, one interval of jumping rope, recovery interval, one interval of sprinting, recovery interval.. and so on. As long as that intense interval is at an 8 or 9 exertion level, and the recovery interval is around 5 or 6, it will work!

Other sources:

Interval training: Can it boost your calorie-burning power?

A Healthy Mix of Rest and Motion

Interval Training

Fit Facts from the American Council on Exercise: Interval Training

And, to assist you in searching for more information about HIIT ---> Google HIIT

I'm kind of skeptical of HIIT.  It's been out for so long, and if it produces such great results, how come it's not blasted over the news the way the Atkins diet is.

Because Atkins appeals to the masses. It's a quick lazy way out. Most people who do Atkins end up putting the weight back on, or once they get used to their new weight they decide that they want to keep it off and move to doing cardio every day and having a good self planned diet. HIIT is not an easy way to lose weight, but it's healthy and effective. It takes a lot of work and motivation, there's no way the news is going to waste time advertising to the few people out there who are willing to completely change their lives to get healthy, that's why we end up here discussing it. 

Do a proper round of HIIT, and you'll discover that easy is the most inappropriate word to describe this type of cardio, and, like many things in life which offer great results, it requires much more work than people are ready to exert.

Same here, which is why I only utilize HIIT once a week in order to stop my body from adapting to my light cardio sessions.

Don't confuse HIIT with HIT; they're two different kinds of training.

HIT, High Intensity Training, is an advanced weight lifting technique using heavy weights, fewer sets, extreme attention to form, a lot of intensity, and training to failure.

HIIT is a cardio technique that alternates intervals of easier and more intense efforts.

Yes, you can incorporate weights into HIIT; however if you're truly doing HIIT, your "easier" intervals are needed for recovery, and you're not very likely to be able to stick to good form if you lift weights during this time. The intense intervals during HIIT should take you near exhaustion.

If you were using good form while you lifted, it's more likely that what you did was circuit training--which is also an excellent training technique. As with HIIT, circuit training also requires a lot of mental discipline. With HIIT you need the discipline to continue even though you're positive you'll pass out in 10 seconds; with circuit training, you need to discipline to make sure you're using good form.

how often should you do HIIT?

 ..thanks for this Goldie

I think the links support it..I started already doing it..

I will see if it works for me ..

anyway..can I do it like everyday for 3 days?..or is it better every other day every week?

thanks!!