The HIIT Hangover

At HAUS No3 we love to train with intensity and to push the envelope every now and then. But we are also big proponents of sharing knowledge and increasing consumer awareness. So we thought it was about time to zoom in on the "HIIT craze" and shed some light on the backside of this highly popular style of training.

Read below to learn more about how you can prevent the “HIIT hangover”.


With a google search for "what is HIIT" you will find the following answer; "HIIT, or high-intensity interval training, is a training technique in which you give all-out, one hundred percent effort through quick, intense bursts of exercise, followed by short, sometimes active, recovery periods..."

At least, this is the intention of HIIT. But since there are no regulations or a standard definition that gyms adhere to - everyone is offering their own version of HIIT and it comes with many catchy names, such as; Xfit, Bootcamp, Grit, circuit training, HIT (high intensity training), etc.

In reality, judging by observations and experience, most gyms around are offering HIIT workouts along the lines of; "timed or task based workouts consisting of movements using mostly free weights or bodyweight performed in intervals or circuits of moderate to intense work followed by usually a relatively short period of rest".


Firstly, let’s lay down some of the great benefit of HIIT;

  • The main reason for HIIT being so popular is the fun factor. Some people just love the feeling after a fast paced workout done with lots of movements and action.

  • When done in groups, HIIT can create a very strong community feel that literally changes lives (just look at the power behind the CrossFit community).

  • HIIT can help people break plateaus and glass ceilings, and really teach people what it means to work hard in the gym.

  • HIIT can boost power output and build some wicked strength endurance.

There are more benefits of HIIT but this article is about bringing awareness to the side effects and pitfalls of HIIT. Something that doesn’t get nearly as much attention as it deserves.


HIIT done wrong can cause early stagnation in progress, lack of results, unnecessary fatigue that leads to nowhere and in worst cases even injury. General movement aside - anyone would agree that if you are going to spend time in the gym you might as well do it right. At the end of the day, people want to see positive results.

Just like a late night at the bar can be fun for the moment but leave you with regrets and a massive headache the day after; it pays to be aware that the HIIT model has some common problems that you would want to watch out for.


HIIT workouts are generally easy for any trainer to put together without a whole lot of expertise or experience. As long as the workout contains a lot of exercises that looks hard, it’s considered a “good workout”.

There are of course exceptions where you can find great HIIT trainers, but since HIIT workouts are often graded based on the entertainment value the trainer brings rather than the actual content and real coaching, it also makes recruiting a lot easier for the gym owner.

For the consumer, this is rather worrisome since it lowers the barrier for required knowledge when hiring of new trainers significantly (ever worked out next to the member who became a trainer the week after?). Therefore, you might end up getting a whole lot of cheerleading, but very little real coaching skills.


To appreciate this problem you have to first understand the original purpose behind HIIT and why it’s claimed to be so effective; the intensity during HIIT should be at max (or close to max) efforts.

If you walk in to any gym offering HIIT and observe the actual intensity of the participants, you will quickly notice that a majority of them aren’t working anywhere close to max intensity. A lot of times this is due to the programming, with over complicated movements, too long work time, not enough rest and too light resistance or weight.

So “HIIT” turns in to something that looks more like “MICT” (Medium Intensity Circuit Training). After a "medium hard" workout like this, you end up accumulating a lot of fatigue for the moment, but not enough stimulus that leads to adaptation in the long run.


Borderline contradicting to the point above, HIIT can also be too much for some people to take or recover from. Often this overload is seen in beginners with poor technique or people who train multiple times per week.

Since training is stress, it's important to realise that without sufficient recovery the body won't adapt well to the stress. Although most people shouldn't have to worry about overtraining, the intensity or volume thrown at people during some HIIT workouts is there with one main goal only; to make people as tired as possible.

In reality, it takes no skill for trainers to create a tiring workout and this should never be the goal. Unfortunately, the amount of accumulated fatigue and soreness from a workout is often how people grade how “good” a workout was.

For someone that wants to lose body fat and is juggling other stress factors in life (e.g. career, relationships, lack of sleep), the volume and intensity from a HIIT workout can lead to nowhere but additional fatigue and frustration. Often, they will ask themselves "how come I'm not losing any weight? I'm working out so hard."

In a case like this, HIIT might be the last thing this person needs.


Naturally, HIIT favours speed and with speed comes mistakes, sloppy movements and technique failure.

It’s not that every movement has to be picture perfect, but in reality most HIIT programs are done with too many high skilled movements and with quantity as a main priority.

When coaches reward and prioritise quantity before quality, you have a problem. Remember, practice doesn’t make perfect - practice makes permanent, and unless you are competing for the win and a big price check, you shouldn’t sacrifice good movement for more work done. At the end it just isn’t worth it.


Hopefully the points above didn’t scare you away from your next HIIT workout. After all, sitting on your butt is not good for you either. And we are by no means suggesting a HIIT-free training routine. However, being able to critically evaluate what you are doing and questioning what you are asked to do by your trainer is being a smart member/client.

Read or blog post “5 ways to quality control your trainer

Due to the fact that everyone is different and therefore have different needs, it’s impossible to give a standard recommendation for how to integrate HIIT in your training routine.

With that said, below are some very general guidelines that we think you should consider if you want to train for fitness and health and avoid the HIIT hangover:

Tip #1: Train HIIT how it was designed to be done; short duration of work, long rest (e.g. 30 sec work, 4 min rest) and close to max intensity and effort (+90% MHR or 8-10 RPE).

Tip #2: For general fitness, aim for 1-2 HIIT sessions per week (when HIIT is performed at max intensity, this is sufficient). Other training days can consist of strength training and steady state, low intensity aerobic training (see tip #5 and #6 below).

Tip #3: Use only low skill movements during HIIT (unless you are competing in a sport such as CrossFit that requires technical movements). This means, very few barbells (if any), BOSU balls or other tools. Instead, stick to less technical exercises/movements that are easy to do even under high intensity, heavy breathing and fatigue (e.g. air bike, sleds, jump squats, etc.)

Tip #4: Prioritise quality of movement over quantity. More work isn’t better unless the work you do is done well. Nobody really cares if you “won” a workout in the gym. It just isn’t worth it, trust us.

Tip #5: Train some form of steady state aerobic training at low intensities (60-70% of MHR) on a regular basis. Learn more about heart rate training at HAUS No3.

Tip #6: Train real strength training (e.g. 5x5 @80% 1 RM with 3-4 min rest). Don’t confuse this for the type of strength endurance you might get from HIIT (+15 reps of <60% 1 RM with short rest) .

With this post, we hope we got you to thinking for a second. Perhaps you even became a bit more aware about the potential side effects of HIIT, not just the benefits. After all, nothing is perfect and the fitness industry is full of so much noise that it can be hard to know who and what to believe sometimes.

Our goal is to speak up, raise our opinion and hopefully share some advice that you find useful.

Visit us at HAUS No3 - located in Naiipa Art Complex, Phra Kanong (BTS exit 4).

We offer personal training, semi-private training and remote training to those who seek a unique training experience.

Click here to book your consultation today.

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