Why Should I Do HIIT?

You may have heard of HIIT (high intensity interval training), or variations of it like Tabata intervals or the "One Minute Workout" and asked yourself, should I be adding HIIT workouts into my fitness routine?  Why should I do HIIT?

You may have heard of HIIT (high intensity interval training), or variations of it like Tabata intervals or the "One Minute Workout" and asked yourself, should I be adding HIIT workouts into my fitness routine? Why should I do HIIT?

There are different ways to define HIIT, but what most definitions have in common is that work at a maximal (or near maximal) effort for a short period of time 20-60sec. Then you generally rest for between 10sec to 2-mins, before repeating multiple few sets.

For some athletes it's necessary and when done right, it's a great tool for those looking to build general fitness in a short amount of time. But there are two types of trainees who it's a bad idea for. Let me explain.



The main benefit of HIIT is that it's an incredibly time-efficient method of staying in shape. And it works. In fact, it can work incredibly well for many people, especially in concert with a well designed, balanced training program. In my experience, HIIT works best for those who are motivated and already somewhat fit. If that sounds like you, and your main goal is general fitness and longevity, HIIT training is a valuable tool for you. It would be worth considering incorporating it into your routine.  



There are two main types of people who HIIT doesn't work well for. One group is athletes with specific needs relative to the demands of their sport. If you want to specialize in endurance events, like triathlon, distance running etc., relying mainly on HIIT training is a bad idea. That's not to say you should never do it at all, but the majority of your training should focus on developing your aerobic capacity over time. The best method to achieve this is with slower paced, longer workouts. If you want to go into a deep dive on this, check out Jan Olbrecht's book "The Science of Winning".  

Similarly, if your main goal is to build speed, i.e. you're a sprinter, do bob sleigh, play certain positions in American Football, etc., then you also don't want to rely on HIIT training. Doing some may provide a benefit, but speed training needs to be specific. You need short distances, max effort, and long rests to allow full recovery. I did another covering the very basics of speed training here, and if you want to learn more, I recommend Charlie Francis's book "The Charlie Francis Training System".



The other group who HIIT isn't ideal for are beginners who're starting with a very low level if aerobic fitness (that means you don't have great endurance capability). For them, a few short sprints of all-out work can easily lead to nausea and dizziness. 

This scenario is most common for those who who've been sedentary for a long time, and especially for larger, stronger individuals who aren’t used to exerting. Because of their strength, they can put out a ton of power in a short period of time, but because of their under developed aerobic system, they have an incredibly difficult time recovering from such hard bursts of work (FYI: your aerobic system is what allows you to recover). 

Without getting into the science, you can see an obvious imbalance here. If we have someone who can push extremely hard, but who can't recover from that effort, and we ask them to do multiple sets of hard work, we're setting them up to crash and burn. There's a good chance they'll feel like vomiting.

For a typical trainee who's at the gym to start building a fitness habit, learn the basics, drop some weight and feel good, that’s not exactly an enjoyable experience that's going to keep them looking forward to coming back.  And going through that pain and discomfort isn't necessary. In fact, sometimes it's counter-productive. A better approach would be to gradually build your aerobic system with slower, sustainable training.



If the answer to "why should I do HIIT training" seems to be "I probably shouldn't", instead of doing HIIT intervals right now, start with 5-15 minutes of steady, moderate effort to build your aerobic capacity - i.e. your ability to sustain effort. This is about pacing and building a base of conditioning. Cycling or fan bikes like the Assault Bike or Airdyne are fantastic for this purpose since they're safe, low impact, and low skill. Anyone can do it, even on their first day. And believe me, it's going to get your heart rate and breathing rate elevated. 

While performing this exercise you should be breathing harder than normal, but your pace should be sustainable for the entire 5-15 minutes of work. If you have to slow down your pace to complete the workout - even by a little - you went too fast in the start. Remember, we're building your ability to sustain effort, not to get tired and have to slow down or stop. So start slower than you think on your first session. 

Many people, not being sure about how to pace, will go out too fast and then die off after 45-90 seconds. If that happens, no big deal. Learn from it. Start slower in your next workout and find a truly sustainable pace.

Complete this workout 2-4 times per week. Every 2-3 sessions, add 1-2 extra minutes of work, or try to go a little faster than before while staying sustainable. Build up gradually to 20 or 25-minutes of sustainable work at a decent pace. This can represent weeks or months (usually months) of work for a novice trainee who was very out of shape when they started. But it provides a nice little progression to build your aerobic endurance so that you can eventually get the benefit of HIIT workouts (or other intensive training methods), be able to recover between sets, avoid the feeling of nausea, and learn some valuable lessons about pacing.

This is a much nicer and better way for deconditioned beginners to ramp up their training. Not only does it work, but they'll be motivated by weekly improvements in performance, build confidence in the gym, and they won't be scared off having to do a workout that feels like death everytime they're in the gym. 

As a side note, learning pacing and the difference between sustainable and unsustainable activity over different time frames is major. As you become a better athlete, understanding different paces, what they feel like and when to apply them becomes important to continued success.