T Nation

Questions About Interval Training


Im starting to do more interval training, and have a pretty good understanding of the energy systems and neural interactions, but still have a lot of questions.

For my purposes, I see two different types of intervals.

1) HIIT and VHIIT. HIIT might be something like 15-30 seconds of work with a rest period of 30-60 seconds. And then VHIIT would be something more like Litvinov where you do somewhat low reps of a "heavy" lift followed by a sprint OR active recovery.

For example, one thing I have done is 10 DB swings followed by 45 seconds walking on a treadmill up hill.

I also understand that an active recovery caters more to developing the lactate system, while a passive recovery allows replenshipment of the ATP-PC system. It seems that there are a ton of different options, and you are either aimed at developing anaerobic power + anaerobic capacity, or aerobic power. What are the implications for what you are trying to accomplish. How should things differ between hypertrophy and fat loss?

I have seen methods that use a HR response to monitor intensities and recoveries, but this only really works if you are targeting cardiovascular changes. If you are doing anaerobic intervals and working for neural and metabolic adaptations, a HR response might not work too well. (For example: a 10 second sprint probably wont get much of a HR elevation, while a 45 second 90% run would)

Sorry for all the confusion, but maybe you can clear some things up.


I'm not an expert at this but I'll try to offer some ideas.

I don't think HIIT has a very important role in inducing muscular hypertrophy. Higher aerobic fitness will make paying the oxygen debt faster after an exercise set, which will help when training for sarcoplasmic hypertrophy with short rest intervals (e.g. 10x10 and supersetting). This can be accomplished with steady state aerobic exercise as well, although it'll take a little more time. [1] Whereas there is some evidence of increased mitochondrial density from HIIT [2], I would guess for a bodybuilder it's completely insignificant.

On oxygen debt, a 10-second sprint would elevate the heart rate considerably due to it. In practice, it's evident in 100m sprinters but it also happens when lifting heavy weights.

I haven't heard of VHIIT before but I would guess such strenuous active recovery, as described, would be detrimental to hypertrophy and strength training. In my opinion, it has no role in bodybuilding. It may be good for athletic performance though.

One possible negative effect of doing HIIT when training for muscle mass might be increased risk of overtraining [3]:

When training for fat-loss, HIIT seems to increase post-exercise fat oxidation. [2] However, whether this will result in any significant difference in the ratio of muscle-to-fat loss, is probably debatable. In total weight-loss it shouldn't have an impact since the EPOC results in only about 200 calories expended throughout the day. (Sorry, don't have time to verify this from a reference right now.) And as we know, total weight-loss is only a matter of energy balance.

One major concern with HIIT when losing fat is the potential for overtraining. I personally learned this the hard way after 12 weeks of dieting and doing about 4 HIIT sessions a week. I would limit HIIT to a maximum of 2 session a week if in a caloric deficit of 500 - 1000 calories per day. After all, you are putting even your heart muscle through extreme stress and not supplying it with enough nutrition to recover.

So in conclusion, I agree with you in that HIIT probably has the greatest benefits in increasing the aerobic capacity. In regard to hypertrophy and fat loss, it probably won't make a big difference.

I recommend reading through the cited studies though. I only browsed them through fairly quickly and have probably missed many things. I'll read them more carefully when I have more time.

  1. Gibala MJ, McGee SL. Metabolic Adaptations to Short-term High-Intensity Interval Training: A Little Pain for a Lot of Gain? Exercise and Sport Sciences Reviews, 2008. (Full text: http://blog.sme.sk/blog/3928/155928/GibalaIntervalTraining_2008.pdf)

  2. Talanian JL, Galloway SDR, et al. Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women. J Appl Physiol 102: 1439-1447, 2007. (Full text: http://0-jap.physiology.org.library.pcc.edu/cgi/content/full/102/4/1439)

  3. Kraemer WJ, Ramsey LT. Pituitary-adrenal-gonadal responses to high-intensity resistance exercise overtraining. J Appl Physiol 85: 2352-2359, 1998. (Full text: http://jap.physiology.org/cgi/content/full/85/6/2352)


if you HR isnt higher after a 10 second sprint
you are not sprinting..

tomorrow go to a field
sprint 100metres, walk back, repeat 10 times

hypertrophy- HIIT
functional (for sport)- VHIIT
fat loss- both


It sounds like you pretty much know what you're talking about. I think to answer your question, there is no black and white, both vhiit and hiit can be successfully used in both hypertrophy and fatloss programs, how you use them would depend on a number of factors, including diet (particularly, how low you're going on a cut) how your body responds to training, and the other elements to your program.

Anaerobic work is going to be beneficial during a hypertrophy phase, and aerobic more-so during fat loss, however, depending on various factors you may choose not to do it this way, or to do both in both.

Sorry I didn't exactly clear things up!


Hi there, very interesting questions.

I'm pretty good with interval training but I'll try to keep to the points

Your general descriptions for types of interval training are accurate.

Firstly, there is the standard type interval training which is usually at about 85-90% of your VO2max (maximal oxygen uptake). Secondly, there is supramaximal interval training, where you should go at intensities that are at a workload to elicit 120-150%VO2max.

The lower range is generally where you can go at a maximal level for just under a minute. The higher range is where you can sustain activity for maybe 30seconds maximum.

Both are really good for performance in sport, obviously what sport you do will determine the intensity level.

Both styles are very effective for boosting fitness (VO2max), and aerobic power (work you can do) by increasing enzymes associated with both aerobic and anaerobic metabolism. You can also enhance creatine phosphate stores and ability to use the ATP/CP system (the really short energy system) with both (although I find the supramax training better for this, some evidence to support but both work well).

Neither type of interval training is really all that good for directly increasing fat loss, or total caloric expenditure compared to lower intensity continuous training. The excess post exercise oxygen consumption (EPOC)associated with interval training is not involved with any significant muscular metabolic process that expends calories. This is a popular fallacy in training.

Now, fibre type changes. Aerobic interval training, just like continuous training, is associated with an increase in the relative number of type IIa muscle fibres (fast twitch, but more fatigue resistant than IIb). This is a good thing for overall performance.

Aerobic interval training does not elicit muscular hypertrophy; sorry, it just isn't at the right relative intensity to stimulate the appropriate pathways for muscle growth.

Session Design Examples

SUPRAMAX INTERVAL TRAINING (after appropriate warm-up)

6-10 repeats, 30 seconds all out effort (cycle ergometer, treadmill, rower, doesn't matter really), 4-5 minutes low level recovery between each effort (fuckin hard and will make you bring up your lunch)


6-10 repeats, max level you can sustain for 1 continuous minute, 2 minute low intensity break between repeats.

Now, it is worth mentioning the "interference theory", which basically relates to the incompatability of doing high intensity aerobic and resistance training in the same program.

Sorry for being a bit long winded, but I love interval training and am quite aware of the research (and application) of these techniques.

If you want to lose fat just go at lower intensities (60-70% for best absolute fat expenditure)for continuous periods of time (minimum 20 minutes).


Good points, GluteusGigantis!

Just a quick note on the following.

Oxygen consumption is directly related to energy consumption. Thus, the increased oxygen consumption does indicate a higher energy expenditure due to HIIT.

On another note, it seems that people get HIT and HIIT confused quite often...


Thanks for all the responses guys, you have given me many ideas.

My goals at the moment are a bit cloudy. My primary goal is strenght, while I want to work on my conditioning as well. Also, in the process im hoping to have a shift in body comp towards less fat. Im not looking to lose weight, and instead want to maintain weight or even increase gradually. So the purpose of my HIIT and VHIIT sessions will not be energy expenditure. Im more looking to it for the metabolic adaptations primarily and some of the neural adaptations (like speed)

I feel im an ecto, although im at around 15% BF, but I think higher intensities are what I need the most. Ive decided to do 4 Interval sessions per week, 2 upper body, and 2 lower body.

For uppper body:

Push press 8 x 5-10 reps /(45-60sec) treadmill walk

Row 8 x 10-20 reps /(45-60sec) elliptycal

For Lower body:

Hill sprint 8 x 10-30 sec work / 45-90 rest walking down

DB swings 8 x 30reps / 30-60 sec bike rest


Jump squat(BW) 8 x 10-20 reps / 30-60 inc treadmill walk

So probably something along those lines. Ive been reading around on interval training, and its really hard to find clear answers as to what works. I imagine if you are training for sport, its much easier, as you would have the intervals resemble the sport.

But for hypertrophy and fat loss, I think I may have figured out a few of the main factors. Assuming you are working at higher intensities 90-100%

WORK duration seems to be the biggest factor. You simply cant recruit maximal MU's for much longer than 10-15 seconds, and thus an all out sprint lasting 10-15 seconds will probably be the best WORK duration for hypertrophy. (This is not to say that a 30 second 90% sprint wont be good for hypertrophy, but it will just be targeting less of the fast twitch MU's)

Also, a short work duration can be optimal for fat loss as well. You might think at first that if 10-15 seconds is best for hypertrophy, then fat loss must be on the other end of the spectrum at 1-2 minutes work. But I would have to disagree.

I think 30 seconds of work, maybe up to 45 sec is the best duration for fat loss. Anything longer, and the intensity will have to drop too much. But in addition to doing 30 sec work durations, shorter ones of 10-15 sec can be very beneficial as well. But in order to gear these shorter sprints for fat loss, REST should be reduced.

REST, rest seems to be equally important to work durations for intervals. A long rest will be optimal for hypertrophy, because it will allow greater intensities during the work phases. Now obviously if you do a 10 second sprint, you dont need to rest 3 minutes (IF YOUR GOAL IS HYPERTROPHY), but for hypertrophy a work to rest ratio of 1:3-1:5 might be good.

For fat loss, shorter rest is what is needed. This range might be 2:1-1:2

Asside from these two primary factors, I would think that intensity and volume would be very important as well.

As for INTENSITY, not only is it going to be dependant work durations, but also on rest durations.

For example:

You could do a 15sec all out sprint for hypertrophy with a 45 sec recovery period. You could also do a 15 sec 90% sprint for fat loss, and pair it with a 30 sec recovery. (the shorter rest duration requires less intensity to b used)

As for VOLUME, im not too sure here. Part of me wants to think that BOTH hypertrophy and fat loss will benefit best from higher volumes, but I dont think this can be correct.

I think for hypertrophy, greater volume should be emphasized but while avoiding fatigue. (I have seen coaches like Staley suggest that intervals be terminated when there is a 10% decrease in speed or performance)

For fat loss, less volume should be the goal but greater fatigue. A drop in performance should be expected.

Other than all of this, I guess you could say that if hyperttrophy is the goal its good to error on the side of TOO MUCH rest, but greater volume, while if fat loss is the the goal its better to error on the side of TOO LITTLE rest, but shorter workouts.

So im not really sure if this is all correct, but these will probably be the guidelines I will be following. And since my current goals are more well rounded instead of just fat loss, or just hypertrophy, i'll follow all forms of progression. (I'll increase intensity on my push presses, i'll decrease rest durations on my rows, i'll increase the duration of the sprints or decrease the rest, etc. And for everything i'll build from 8 rounds up to probably about 12, at which point I would decrease back down to 6-8 and increase the intensity once again.)

Thanks again guys.


I made the mistake once getting HIT and HIIT confused. Ya but I think what he meant is that EPOC is not significant in increasing caloric expenditure. I haven't seen any studies, but I doubt you are going to elevate your metabolism by even 10% from one HIIT workout. So if you are burning about 3000 cals a day, even if you did get 10% that would just be an increase in 300 cals burned. This deficit would be much more easy to get by just eating 300 less cals. So I think thats the point, that HIIT isn't about EPOC or calorie expenditure, but instead about the fitness demands, and supporting more muscle.


Yep, you've got some good program ideas there Dankid, and you're bit at the end is spot on.

Although oxygen consumption is an indicator of caloric expenditure, although not necessarily an indicator of muscular metabolism happening post interval training, your metabolism just isn't raised enough for substantial fat loss.

There is great research out there on interval vs continuous training.

Good luck with your training; see what happens with your plan.

Usually with an athletic population, I make sure they have a good base fitness level to start with (ensures good numbers of mitochondrial proteins and oxidative enzymes, good muscle function, used to hard sub-max training), good strength level, then introduce them to interval training. Its a great way to get your muscles in shape, as you said.

The concern about the interference theory is very real; the problem is that we just don't know the best way to combine things at the moment (same session, weights before aerobic=yes; what volumes of each, interval and weights, you can do during a week without having interference, we're not sure).

Just keep an eye on your lifting volumes, loads, and physical gains. Find what works best for you and ROCK IT OUT!!!!!


Thanks for the support gluteus.

I didn't mention my resistance training, but its basically a 2x per week Push/pull. Each workout will start with my "strength" exercises supersetted which will either be frontsquat/bench or deadlift/pullup.

Then i do 2-3 assistance exercises for 1-2 sets high reps to failure and shoot for PR's in rep numbers. And the strength training is somewhat low volume probably doing 3 sets of 1-6-1-6-1-6.

We'll see what happens.


It's great that you guys are into the science of training but I honestly think you're losing the big picture here.

If you want to gain strength, go for 5x5, Westside training or other method that's proven to be effective. Do not use active recovery methods.

If you want to gain muscle, use 10x10, Max-OT, DC training or other fairly well proven method. Do not use active recovery methods.

If you want to improve your aerobic fitness, do HIIT or steady-state cardio in a way it's been proven to work. If you wanted to be scientific about it, I'd recommend reading studies - not T-Nation or any other articles because they are second-hand information.

And train only ONE of these attributes per training session.

I know this may seem too restrictive and boring but honestly, if you devise custom programs based on a few tidbits of theoretical information, you will end up with a program that doesn't work. In what you've described, there are many flaws resulting from holes in scientific knowledge.

[b]The little things (like TUT, EPOC, GH output or even things like supersetting etc.) just don't make a difference in the big picture and often eliminate the factors that would have made the program work (like progression, energy balance and consistency).

My advice is to keep on studying and learning BUT use training methodologies that have been proven to work and only modify them a little to suit your personal physiology IF needed.[/b]

I hope you know I'm not trying to put you down at all guys - I just hope to save you from a lot of wasted effort. You've come a long way with learning all of this information and I hope you keep on going.

I know it's very tough love but I wish someone had told me this in the past as well. In fact, someone did but I chose not to believe it and wasted many years of training "experimenting".


I agree tero, but I think interval training is one of the areas where the research and practical methods aren't very clear. Ive taken a number of exercise phys classes and read numerous articles and books, but there are many different methods, none of which can be claimed as the end-all be all best. Like I said, its easy for athletes, because they know the demands of their sport. But for average joes looking to use interval training, any of the methods could be beneficial. For me, the only thing im AVOIDING is longer duration intervals and endurance training. I think this is the only type that will give me the opposite results of what I want. All types of interval training will be counter-productive for strength, thus if you are focusing on max strength during a session, sure intervals are a bad idea. But there are many different options for intervals that combine "heavy" lifts with sprints or active recovery that will have benefits for hypertrophy, fitness and fat loss.

For me, during my current plan, strength is going to be top priority. If my lifts begin to stall, then my interval training sessions will be the first place I cut back. If you look at the Litvinov article, Dan john mentions that Litvinov would do sets of 8 on front squats, and then run a fast 400m in between sets. This is potentially a great and demanding workout, but if you are only squatting 135 for 8 you'd be much better off, just focusing on the strength.


Your tough love is unwarranted physio, but your intent seems fine.

I haven't, and never would, advocate interval training for active recovery, and I definitely haven't based what I wrote on tidbits of knowledge picked up from T-Nation.

As I made clear in two of the posts, there is alot we don't know about the potential interference effects of doing high intensity interval work and resistance training in the same program (for any research paper showing interference, you can find another that shows none).

Considering the high number of elite sportspeople I've worked with who HAVE to combine high intensity interval work and resistance type work on a daily basis, I haven't seen them suddenly explode or shrink owing to this combination. Many, many athletes combine this type of training all the time and look great and perform even better.

Obviously in the context of bodybuilding more caution is warranted.

What Dankid wants to do is fine, and his approach seems good. But as you said, each individual may respond differently so lets see him go for it and assess his progress.

So when is your first training Dankid?


Well, Ive sorted already started this type of training, but the first week was a bit experimental.

Today, im going to do a hill workout, 8 x 30s/60s @ about 90% intensity.

Ive been doing the two strength sessions per week, and using 5/3/1 but now am gonna go to 1-6. Yesterday I frontsquatted 245 x 3 a PR for me which was heavy, but not horrible. And I was pretty excited with that. My interval sessions are pretty tough, but usually only last about 12 minutes at the moment. I haven't tried the push press intervals or the DB swings so those should be fun.

I posted my strength goals in another thread recently, so now really all I gotta do is continue to pursue those. And the interval training i'll play around with adding sets, decreasing rest, and changing the other variables to see if I can cut down my BF a bit. BUT, im not looking to lose weight, so this process may be slow.

I should have also mentioned that although this is a bb'ing forum (questionably) im not trying to be a bb'er in any way. I just want to be "big" strong and fit. If anything im trying to be more like a strongman but I know I wont ever be 6'4 and close to 400lbs.