I currently do a 1:2 ratio of high to low intensity. My high intensity interval lasts 60 seconds, and my low intensity one lasts 120 seconds. I do this on either the elliptical or the heavy bag (I'm forced to shorten the intervals on the heavy bag due to the large amount of energy exerted).

I know that over time, you should increase the ratio until you hit 2:1 high to low, which is generally agreed to be the sweet spot for HIIT.

The problem I'm having is figuring out how long the intervals should be. I've seen suggestions as low as 20:10 seconds (known as Tabata) or as high as 120:60 seconds (intervals higher than that don't appear to be considered HIIT). Is the length of the interval simply not as important as the ratio?

2 Answers 2


Long enough that you're pushing against your limits, short enough that you're doing it the whole time.

If you find yourself feeling/thinking at the end of a high intensity inveral "hey, I could have gone on a little longer!", then it's too short. Same if, at the end of the last interval, you're not thoroughly exhausted.

On the other hand, if you you find that you're pacing yourself or slackening towards the end of an interval, i.e. you can't keep it at full intensity throughout, then it's too long.


Don't focus on the specific ratios; they don't matter much. As long as the ratio is in favor of the high intensity exercises, you have little to worry about.

Your goal is to keep increasing the duration of the high intensity per exercise. This strengthens your stamina, endurance, heart, and lungs. Of course, it also burns calories like crazy!

The 20:10 ratio is too low for a reachable goal. Many exercises in P90X and Insanity videos use 60:30 seconds ratio; this is because the whole video lasts between 45 mins and 60 mins. Depending on the total time allotted for the exercises, you might want to aim for 120:45 seconds ratio (yes, it's tough, but that's why it's a goal :))

The length of the interval is much more important than the ratios. The calories you'll burn (and all the benefits you'll derive from the program) depend on how much time (and the intensity) you apply to them; the ratio's simply a way to measure if you're improving or not. A 30:60 ratio indicates that you aren't pushing yourself enough (indicating your body needs more strength and stamina). However, as long as you're getting up there and giving it your best, that's great and the numbers will improve.

Oh, one more thing: keep being awesome through exercises. :)

  • "increasing the duration of the high intensity per exercise" makes perfect sense...but it's also in disagreement of the popular "Tabata" routine which uses 20 seconds of high intensity and 10 seconds of rest. It's difficult to figure out whether the longer intervals are better than the short ones, but perhaps it's a matter of "to each his own".
    – TonyArra
    Commented Apr 14, 2014 at 3:07
  • @TonyArra I'm not aware of Tabata routine; however, 20 seconds high intensity is for beginners; as you become fitter, you'll realize you aren't getting much bang for your buck. Also, 10 seconds rest is too small. I doubt that many people who rest that short a duration will be able to perform better in the next exercises. I recommend a minimum of 30 seconds low intensity/rest (10 seconds to catch your breath, 20 seconds to deep breath) . I know that Insanity and P90X videos use similar durations too :). More importantly, you want to challenge your body, not stick to a routine. :) Commented Apr 14, 2014 at 4:13
  • I am aware of the Tabata training. For tabata, 20-40 seconds max due to the strictness of the recovery and the type of exercise selected/ number of repeats etc. For standard interval you can work for longer, but obviously the recovery would be longer. Commented Apr 14, 2014 at 6:02
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    @Kneel-Before-ZOD The difference with the Tabata routine is that it was actually tested in a medical experiment (by a doctor Tabata, in fact), so we know it works. The 20/10 interval (you do 8 of them generally) is enough bang for the buck if you choose a difficult enough exercise. In the end, you should just tune your intervals to the demand of your sport (eg. if you're boxing, then 2min/1min or whatever) -- if you don't have a particular sport, then might as well Tabata.
    – VPeric
    Commented Apr 14, 2014 at 11:55
  • @VPeric Granted that P90X and Insanity weren't developed in a lab; however, the results they generate (amongst the millions who have used them) prove that it works as well (without having a particular sport) . If your goal of cardio is to increase endurance and stamina, you won't accomplish that with a 20:10 seconds. Either you'll cheat or you'll realize it doesn't help you after a couple of months. To regain your energy after a high intensity training, you need to breath deep slowly. Catching your breath and doing that will take more than 10 seconds. Commented Apr 14, 2014 at 13:06

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