Best workout apps we've used: improve your fitness in just 20 minutes a day

High-intensity interval training (HIIT) has been gaining in popularity recently, and for good reason – a workout that promises big results from short workouts is going to sound pretty appealing to people who are short on time. HIIT even came to the Apple Watch in watchOS 4.

Here we will explain a little bit about what HIIT is, and a few apps that you can use to for this new workout method, which is exhausting but has the potential to super-charge your results.

There are three different energy systems used by your body during exercise, one aerobic system that uses oxygen as fuel, and two that are anaerobic, using lactic acid and phosphates as their fuel. Long-duration cardio training (running, swimming, cycling) is dependent on the first of these energy systems, as it's the only energy system that can continue to feed muscles for long periods of time. 

The problem with this is that low-intensity training burns a relatively small amount of calories, so in order to achieve a caloric deficit for weight loss, a large amount of this exercise needs to be done. 

High-intensity exercise, on the other hand, burns a large amount of calories, but you’re unable to sustain it for long enough that it makes a significant difference to overall fitness. 

HIIT bridges the gap between the two training disciplines by interspersing short periods of high-intensity exercise with periods of low-intensity, to help you recover while still burning calories.

Does it work?

One of the most popular forms of HIIT is something called Tabata training, which is eight rounds of 20 seconds maximum intensity and 10 seconds low intensity. If you’re doing the math and thinking that only works out at four minutes of exercise, you’d be right – but done right it will be one of the worst four minutes of your life.

Tabata training was developed as a method of training by Japanese scientist Dr Izumi Tabata, as a method for improving the sprint times of Olympic ice skaters. 

He discovered that by doing these short bursts of maximal effort interspersed with periods of low effort, not only did the athletes get similar aerobic gains to a group doing a much longer more traditional workout, but they exhibited anaerobic gains that the control group didn’t show.

To oversimplify this, it basically means that if you work smarter, you can get the same – or even better – results as from slogging away for ages on the treadmill. Plus, as a little bonus, you get the benefits of an effect called EPOC, which stands for excessive post-exercise oxygen consumption, which basically means that as your body works to address the oxygen deficit in your system you keep burning calories long after you've finished exercising.

As this is a very intense form of exercise, it puts strain (good strain, but strain none the less) on your heart, lungs and muscles. You should consult a doctor before starting any exercise regime, especially one as intense as HIIT.

Enough science! How do I do it?

You basically need three things for HIIT: an exercise of your choice, will power, and a timer. 

The exercise needs to be something you can do for extended periods of time. Static bike is perfect, because it’s easy to shift quickly between low and high intensity. Running machines can work, but they need to be set up to alternate between the intensities, and, depending on your level of intensity, it can get risky having sudden changes of speed that are happening out of your control.

Rowing machines and elliptical machines both work well too. The elliptical machine is actually one of the best in terms of getting a full-body workout, but for some reason has a stigma attached to it. 

A lot of people do burpees as a HIIT exercise, which seems to make sense because it’s a full-body exercise, but the fundamental problem with these is that you're likely to reach muscular fatigue, which will inhibit your ability to push yourself to your desired level of cardiovascularly. 

If you don’t have access to a gym, or would just prefer to do your exercise using body weight, then skipping, star jumps, and even jogging on the spot can all be employed.

Timers. You mentioned timers…

This is where the tech comes in. Obviously you could use a stopwatch to set your periods, but frankly who has time for that? Luckily there are a number of apps on the market specifically designed to help you plan and carry out your HIIT session. 

There are so many to choose from that the selection process can be pretty daunting. To help you out, we've chosen our favourites…


Seconds is an app for creating your own exercise timers. It has templates for circuit training, Tabata, HIIT, and custom timers. You can adjust the length of the high- and low-intensity periods, you can adjust the number of sets you’re going to be doing, and you can name the exercises – so if you’re doing a circuit it’ll tell you you’re on the kettlebells next. 

During your workout it gives clear audio signals for starting and stopping, and the screen has a massive countdown on it, so even when sweat is streaming into your eyes you should still be able to see how long you have to go before you can rest. 

Seconds is free to download and use, but gives you the option to upgrade to Seconds Pro, which allows you to save timers; very useful if you're going to be doing the same workout four times a week.

Runtastic Timer & Intervals

Runtastic, as the name might suggest, is from a running company, but don't let that put you off. A timer is a timer, and this is a good timer, and the app is easily the most aesthetically pleasing of your options.

It's very easy to customize, and can either give you beep prompts or voice feedback.

Like Seconds, it's free to download, but if you want to unlock the full range of timers and get rid of the ads you can pay a small in-app fee. 

Tabata Timer Interval Timer

Tabata Timer has a very simple interface, but it does everything you need of it. When you open up the app it gives you the option to change your prep time, work time, rest time, and number of cycles. Once you’ve put your desired specifications in, you just hit Start and away you go. 

Tabata Timer works in the background, so if you want to move over to your music app mid-workout you’re not going to stop the timer, which is surprisingly useful. Also, Tabata Timer works with Google Fit, so if you use that app it’ll transfer over your data from your workout.

Tabata Timer is free to download, with the option to upgrade to the premium version (with a number of different affordable plans) if you want to save more than two workouts. 

What about the willpower?

That's up to you. Sorry.