The benefits of HIIT (high intensity interval training) are so numerous that condensing them down to one list is pretty tough going.
But I’ve got it down to 21 for the purposes of this article.
These have been well known in strength and conditioning circles for decades. But cardio exercise using a HIIT method is somewhat new in general population exercise.
As a personal trainer, my go-to conditioning approach is HIIT. For many of the reasons, I’m going to share in this article. It isn’t because it’s ‘new’, or ‘exciting’ – it’s because it is downright effective.
My job is to help clients achieve results, not to be entertained (although if you can do both, it’s a bonus!)
Thankfully, HIIT successfully blends results with endless workout variety.
To make this easier to consume I’ve broken it down into 4 main sections:
I’ve included scientific research to back up these claims. But I also use my anecdotal observations over my 20-year career as a personal trainer.
- 6 Physiological benefits of HIIT (& performance benefits)
- 2 Benefits of HIIT for mental health
- 2 Health benefits of HIIT
- 11 Reasons HIIT is fun & suits most people
- 11. HIIT allows for a lot of training variety
- 12. HIIT can be done with cardio or resistance training
- 13. Full body HIIT workouts are possible
- 14. HIIT is completely adjustable to the goal
- 15. HIIT makes the training time efficient
- 16. Reduced excuses with HIIT
- 17. There’s endless creativity with HIIT workouts
- 18. HIIT can be done effectively without any equipment
- 19. HIIT can be worked around lots of injuries
- 20. Easy to outsource HIIT coaching
- 21. HIIT is perfect in a home gym – equipment dictates the workout
- Benefits of HIIT – the bottom line
6 Physiological benefits of HIIT (& performance benefits)
1. HIIT burns a lot of calories
From a pure energy burn perspective, high intensity interval training is a very effective approach. You burn a lot of calories by pushing your body beyond its normal maximum intensity during training.
In a comparison study from 2015, researchers assessed the calorie burn of 4 types of training:
- weight training – 8.83 ± 1.55 kcal·min
- steady-state cardio (70% max HR on a treadmill) – 9.48 ± 1.30 kcal·min
- steady-state cardio (70% max HR cycling) – 9.23 ± 1.25 kcal·min
- HIIT – 12.62 ± 2.36 kcal·min
The results showed that HIIT burned around 25% more calories in the same amount of time as the other approaches.
2. HIIT builds stamina and VO2max
One of the most commonly sought-after benefits of HIIT for the heart is improvement in stamina.
In particular, VO2max (a measure of how efficiently your body uses oxygen). Generally speaking, a higher VO2 max translates into better stamina.
A study assessed the impact of a specific HIIT approach over a short (2-3 week) period.
The results were crystal clear… even in active men and women, the data showed that HIIT significantly enhanced VO2max and O2 pulse and power output.
3. Great for sports training
Most sports mirror HIIT in nature, because they’re stop-start.
They mix periods of very high intensity with rests and they are time fixed. Rarely does a sport require a perfectly constant amount of effort for a sustained period of time. Unless it’s a pure stamina event.
This makes HIIT an excellent training option for improving the stamina and recovery ability of athletes from particular sports.
You can design the workout to reflect particular work and rest intensities. And can pick a different format depending on the sport. So you can use weights, running approaches, cycling, etc.
Just check out our HIIT workouts here if you want to see a huge variety that can be suited for all types of sports.
4. HIIT helps to reduce injury rates
Movement patterns and quality are linked directly to injury frequency.
If you take runners, for example, the repeated movement pattern can lead to high injury rates. When you factor in poor-quality movement, the issue is even greater. Reduced flexibility and poor movement directly lead to a greater frequency of injuries.
HIIT that requires a variety of movement patterns within a training program will help to prevent overuse injuries. If, for example, your training was only running, cycling, or swimming, you’re repeating patterns over and over again. This often causes increased injury risk.
This is one of the main benefits of HIIT for seniors and the aging population. If you get injured when you’re older it’s much harder to recover and continue to exercise.
5. Unlike most cardio, HIIT actually helps to build muscle
One of the reasons cardio gets a lot of bad press in bodybuilding and physique circles is because it is associated with muscle loss.
There’s an assumption that long-term low-intensity exercise will lead to muscle atrophy. Whereas high-intensity exercise will maintain muscle mass.
With HIIT, there’s plenty of scope for heavyweight exercise that will not only prevent muscle loss, but it’ll also help to actually build muscle. In my gym, we use prowler sleds (see an example here) and heavy tires (example) with a HIIT approach for this reason.
It helps to elevate the heart rate and build functional strength and muscle at the same time.
Also, check out this barbell Tabata from our list of HIIT workouts.
Below I show you how to do a Prowler TRX power row…
6. Greater results are achieved in less time with HIIT
By pushing the body to higher workout intensities, the speed with which results come is reduced.
There’s also evidence that the improvements using the approach are better than with traditional ‘steady state’ cardio.
In research from 2007 comparing the two approaches, the HIIT group improved VO2max by approximately 10% in 8 weeks. Whereas the steady-state training group improved by 5.5-7.2% despite the same volume of training.
Use HIIT rather than steady-state training if you want to improve your cardiovascular capacity faster.
2 Benefits of HIIT for mental health
7. HIIT helps to improve mental health
The link between exercise and improved mental health is well established.
But could there be an even greater improvement in mental health when you use HIIT? Thanks to recent research published in 2021, we have an answer!
The study involved 67 people following a 6 week, 6 days per week program with 40 minutes of exercise per session. The results showed that HIIT and moderate-intensity exercise (MIT) significantly reduced stress, anxiety, and depression. It also increased resilience in the subjects.
Moreover, the improvements obtained in the HIIT group are greater than in the MIT group when it came to depression.
This is one of the key benefits of HIIT for the brain.
8. HIIT is endlessly motivating
One of the aspects of HIIT that my personal training clients love is the fact that there’s always a new challenge.
We have nicknamed one approach ‘bardio’ – this is a cardio HIIT workout with the barbell, hence the name bardio! This has the unique benefit of taxing the muscles whilst shooting the heart rate through the roof!
You can see an example bardio workout here.
This triple threat of cardio, strength building, and muscle building is why the approach works so well. One study looked into combining multiple exercise approaches in the same workout program. They found this to improve multiple fitness qualities at the same time.
Which is both motivating and effective.
The great thing is that this motivation leads on to the proven benefits of exercise on mental health as you can see here.
2 Health benefits of HIIT
9. HIIT is perfect for diabetes sufferers
Fundamentally, diabetes is a problem metabolizing blood sugar (also referred to as blood glucose).
One of the most common sense things you can do for diabetes is exercise. Because it burns sugar to fuel the movement. This in turn helps your body to regulate blood glucose levels.
The beauty of very high intensity exercise is the high sugar burn nature of it. When exercise is very high intensity it burns a lot of sugar relative to fat as a fuel, which helps to keep blood glucose under control. Research shows us that high intensity exercise helps to regulate and control blood sugar levels for up to 3 days post-exercise!
This can be a literal life changer.
10. There’s a lower risk of injury with HIIT
There comes a point when more training volume becomes counterproductive. And you end up increasing the risk of injury or overtraining. Something I’ve personally suffered from in the past.
With HIIT, your risk of overtraining and injury is inherently lower. Because the training time and volume are significantly reduced.
A 2018 study looked into High Intensity Interval Training performed by young athletes. Researchers learned that the average length of a HIIT session was 28 minutes. As opposed to 38 minutes for other groups. This 10 minutes per session adds up to a significant reduction in training volume over the course of a year. Dramatically reducing injury risk.
Mixing movements also helps to reduce injury risk.
11 Reasons HIIT is fun & suits most people
11. HIIT allows for a lot of training variety
Anecdotally, I know this from my career in personal training. One of the sticking points for people who are ‘forcing’ themselves to exercise is boredom.
They need new stimulation to maintain interest.
The thought of going for a run, swim, etc. can be nightmare-inducing. Especially if you don’t naturally enjoy exercise, because these are so repetitive.
This is the bar that we recommend for ‘most people’.
We have spent over 120 hours of research and tested over 100 barbells.
It is affordable but comes with some high specs. The Rogue Work Hardening and 190k PSI tensile strength mean the bar will last a lifetime in a home gym.
It is a multi-purpose bar with a 28.5mm diameter shaft and composite bushings in the sleeves. This means it’s balanced for heavy slow bench presses but you can also perform snatches and fast overhead lifts.
With HIIT you can mix in a lot of training variety. You can adjust the length and number of work sets and rest periods. You can adjust the intensities, you can set challenges and mix up the workout easily. What this means is that motivation remains high because the variety is there.
It keeps the challenge aspect of the training fresh.
12. HIIT can be done with cardio or resistance training
This is something a lot of people overlook…
The fact that you can do HIIT as a cardio or resistance training approach.
In fact, you can even train them both concurrently. The protocol remains the same! Mixing periods of high intensity training with periods of lower intensity rest. Regardless of the equipment used to do the work with.
Again, I’d highly recommend checking out our HIIT workouts. I can guarantee you’ll find a new idea in here, especially if you have only thought of HIIT as bodyweight cardio routines.
HIIT with kettlebells, dumbbells, barbells, cardio or even a mixture of them all is possible. In many ways, it’s preferable for the general exerciser. In fact, CrossFit has built an entirely new sport using variations on this as a basic theme.
Short, hard workouts with lots of variety.
Check out the GOAT of CrossFit, Mat Fraser doing this Tabata workout for inspiration…
13. Full body HIIT workouts are possible
This is obvious to a lot of people who use HIIT regularly. But many newbies to the approach forget they can mix things up!
Instead, many people stick to the cardio-based HIIT using one item of equipment or exercise method.
With a resistance exercise HIIT training plan, you can perform a full-body workout. They can challenge your strength, your muscle endurance, and your cardiovascular capabilities all at the same time.
In fact, for the general exerciser who has a nonspecific ‘get fit and build muscle’ as their goal, it’s arguably the best approach. Mainly because it ticks a lot of boxes in one single workout.
14. HIIT is completely adjustable to the goal
A training protocol that is based on high intensity intervals of exercise can be adjusted to almost any goal.
If you want to build muscle, you can use high intensity training approaches. If you want to improve your stamina, you can use high intensity training. There are even versions of high intensity yoga such as Ashtanga, ideal for flexibility.
Used properly, HIIT is a very effective muscle-building approach as well.
Most people associate it with cardio and VO2max improvement. But very high intensity weight training is an efficient muscle builder. In fact, Dorian Yates (6 times Mr. Olympia champion) credits a version of high-intensity training with helping him build his physique. This took him to the absolute top of the bodybuilding world…
15. HIIT makes the training time efficient
When you train at a very high intensity, you don’t need to train for as long.
You get the same amount of work done in a shorter period of time. To put this to the test, researchers from Canada devised a workout protocol. It involved a maximum of 12 minutes of high intensity exercise per session, 6 days per week.
The results were conclusive, showing that…
“A practical model of low volume HIT is a potent stimulus for increasing skeletal muscle mitochondrial capacity and improving exercise performance.”
Basically, if you work hard, you can work fast!
You can fit HIIT into even a really busy day.
16. Reduced excuses with HIIT
One of the most common excuses for people not exercising is they ‘don’t have time’.
The HIIT protocol basically destroys this, because it proves that you can do a really effective workout in significantly less than 30 minutes. In some cases, it’s possible to do it in less than 20.
Another excuse is that people find exercise boring. But with HIIT you can pick any type of training that you like.
If you’re not into gyms, you can run, swim, cycle, skip, dance or whatever. The point is you do it hard, and do it fast. You’re only limited by your creativity. Even if your equipment options are limited you’ve still got bodyweight work.
17. There’s endless creativity with HIIT workouts
Stagnation in exercise is a real motivation and results killer.
When you perform the same workouts over and over again your body becomes used to them. Your movement becomes efficient and your results decrease because it takes a lot less effort to perform the exercises.
With HIIT you are bound only by your creativity.
You can keep your body guessing! Simply add weights, kettlebells, cardio rounds, adjusting intensity levels, length of sessions etc. Mix things up again if you get bored or your fitness stagnates with HIIT. You’ll be refreshed physically and mentally!
18. HIIT can be done effectively without any equipment
When my personal training clients travel for business, they don’t always have access to a gym.
They can still stay active with HIIT workouts.
The approach is my go-to for personal training clients who are on the road. Even if they don’t have any equipment, they can still perform it.
A simple HIIT workout can involve sprints and recoveries, bodyweight exercises, or a combination of the two. It means that even without equipment you can perform a great workout on the road.
You really don’t need much. In fact, here’s a workout you can do in a small space such as a hotel room. Or you can find a ton of YouTube videos like the one below…
19. HIIT can be worked around lots of injuries
HIIT can be tweaked endlessly to train the whole body and can be adjusted to avoid injuries.
This is somewhat different to single-approach exercise patterns.
Say, for example, you only ever run but you have a knee injury. You won’t be able to run no matter what you do to adjust your running workout.
With HIIT, if you have a knee injury you could do an upper body workout. You aren’t tied to one style of exercise, you can adjust it to suit your goals and situation at a given time. This means you can maintain your cardio fitness even if you have an injury that prevents traditional cardio.
20. Easy to outsource HIIT coaching
The approach has grown in popularity over the last few years. This means a lot of coaches and tech companies have jumped on the HIIT bandwagon.
HIIT timers and HIIT workout coaching apps are endless now.
It means you don’t have to rely on your own creativity in order to put together interesting workouts!
I don’t use any myself (I do this for a living!), but there are lots of them out there. They will help you keep time for the intervals or even give you a few workout ideas yourself. You don’t have to use them for every workout.
But they may provide you with a bit of inspiration on those days when you just need a little outside thinking!
If you’re looking for inspiration I do highly recommend that you check out our HIIT workouts article. There are so many variations in here alone. But more than that, it will get your brain ticking about the possibilities that suit you and teach you how to design your own.
21. HIIT is perfect in a home gym – equipment dictates the workout
HIIT in a home gym is a perfect excuse to use equipment in new ways that you hadn’t previously considered.
Giving your home gym a new lease of life!
Think of the ‘bardio’ concept I gave you earlier – taking a barbell and using it for high rep, light weight work as opposed to only strength training. (Check out our best Olympic barbell guide where we compared over 100 barbells to leave you with the best one).
You might even take advantage of space and equipment you’ve overlooked. Which would help you get more out of your home gym. In lockdown, I had clients of mine doing plyometric work on their pull up bars (jumping pull ups) and complexes with kettlebell. This had them look at equipment in a whole new light.
You can learn how to build a home gym on any budget here. Also, be sure to check out our gym equipment guides and reviews. Thousands of hours have gone into this to save you the time of having to figure this minefield out yourself!
Benefits of HIIT – the bottom line
I said at the top of the article that HIIT is my go-to approach for cardiovascular and endurance work.
For myself and my personal training clients!
It’s also heavily used in my general programming for fat loss and general fitness. This isn’t because it’s fancy or fun – it’s because it’s effective.
I’m a professional trainer. I’m not paid to entertain, I’m paid to get results. If HIIT wasn’t effective, I wouldn’t use it.
I can’t give the approach a higher compliment than that. It’s…
- And allows me a lot of freedom and creativity with my programming.
Those same benefits are afforded to you in your own training at home.
I hope having read this article on the benefits of HIIT you decide to include some of the approaches into your own programming.
If you need some inspiration be sure to check out our guide on HIIT workouts. It includes examples and explains how you can design your own HIIT workouts to meet your goals.
If you want to focus on weight lifting ideas, be sure to check out our more advanced weight lifting workout.
If you’re up for another serious challenge, check out our advanced bodyweight workout plan.