T Nation

HIIT Questions


Got to discussing HIIT with someone, and the issue of the rest intervals came up. Now most people do a timed max of near max effort, with a timed recovery period, whatever that may be. 15 on, 45 off, whatever. I have even seen 30 on, 90 off. We wondered if a heart recovery measure would be better. Initially 15 second all out bursts, wait until heart rate returns to a set level, then burst again. Curious on what people's opinion is on this.

Now I know there are other factors, such as how many bursts, when to up the burst time....We even discussed that. We discussed what the recovery rate should be. That has to be highly individual. 150 at the absolute highest level of heart rate to signal the start of the next bout we thought. When the thought of how many bursts, we settled on minimum of 5 for untrained people to start, but adding another burst if the recovery time is less than 90 seconds.

When 10 bursts are done, up the burst time 5 seconds. When 10 bursts of 30 seconds can be done, change the exercise. The parts that we liked are probably the parts that would stop people from doing it. 1) lots of thinking. 2) it is self limiting. If you slack, you are just hurting yourself.

Thoughts? We also thought that if someone were to use a lower body exercise, then 2 sets each of a push and a pull upper body exercise, increasing the weights when a rep goal is reached. If using something like an upper body resistance machine, UBE, then 3 sets with standard progression with the squat.


I always think you need less rest after interval 1 than you do for interval 7 so it makes sense to rest slightly more for each interval. What I did yesterday was simply 8 sprints lasting around 10-15 secs until i was no longer accelerating, then rest until I felt powerful enough to go again. It may have been a 30 second rest at the start and maybe a minute at the end. I don't think it needs to be precise. I understand that if I don't push hard enough then I won't lose enough fat, and I really want to lose fat. Also if I don't feel that great I can take it slightly easier but still get a good workout in. Basically the same as autoregulating a weight workout.


That's a good approach. accelerate until you can't. Thanks for that idea


I think it's kind of a cool idea., But here are my two issues with it:

First, like you said, it's simply too complicated to be realistically done on a regular basis

Second, I wonder if it would cause people to rest longer than they actually need. Maybe, maybe not.

But, I do like the idea of accelrating till you can't as well. Kind of cool.


I have used that idea before. Doing a hill sprint and using heart rate as a means for determining when to do the next set.

The first problem I ran into was everyone was so different I had one woman whose heart rate didn't get back down to the level we set (I think it was like 70%) for nearly 10 minutes. She was literally sitting there bored to death but her heart rate was stuck at about 80%. That was the last time I used that method.

I think there is a great deal of merit into testing it and looking into it more closely though.

Justin Cox, CSCS


when i train on the bike, i do bursts, and intervals both ways. some with hardly any rest, some with medium rest, and when gearing for a huge race, short med and long intervals with a lot of rest in between. just depends on your goals.


I always use a heart rate monitor (chest strap) when doing hiit. I set it to alarm at 75% & 95% max heart rate. I sprint till i hear the 95% beep & try and hold that for as long as i can (usually about 10-15 sec), then i stop and walk back to the start and wait till i get the 75% beep and go again. So initially the rest is short, but as i fatigue the rest period starts to blow out. When i feel like its taking me too long to recover & drop to the 75% mark, I stop.

Personalized Hiit rather than some arbitrary numbers.