If you're thinking about subscibing to The Body Coach app, or you're a member of your local gym or follow fitness trainers on social media, you've probably heard the term HIIT being thrown around. But what is it, why should you be doing it and can you really get results in just 20 mins? We answer all your burning HIIT questions.

What is HIIT?

HIIT stands for high-intensity interval training. It's a way of training that combines quick, intense bursts of exercise, where you're working out as hard as you can, with short periods of recovery. Getting your heart rate up to a level you can't sustain for long allows you to burn more fat in less time, making it an especially effective workout for those with a busy schedule.

This form of intense training has been a big buzz in fitness for the past few years, topping the Worldwide Survey of Fitness Trends for 2018.

But if you're not sure exactly what's involved, it's hard to know where to start. Which is why we've compiled this beginner's guide, taking you through the benefits, explaining how it works, and including a beginner Body Coach HIIT workout to try once you've learnt more. So let's get started.

What are the key benefits of HIIT?

1. You get more energy burn for your buck

Studies show you can burn 25-30% more calories during a 30-minute HIIT workout than you would doing weight training, cycling or an endurance treadmill session for the same amount of time.

2. It boosts your metabolism

Working out at an intense level means your body uses more oxygen so your metabolism has to start working harder. As a result, you keep on burning energy even after you stop working out.

3. It can help you lose body fat

One study found that people who did three 20-minute HIIT workouts a week lost 2kg of body fat over three months. This was without making any changes to their diet. They also saw a 17% reduction in their visceral fat – that's the fat surrounding your internal organs, which can lead to health problems such as type 2 diabetes.

4. It's great for your overall health

HIIT training has loads of health benefits, including strengthening your heart and keeping your blood pressure in check. Just three 20-minute HIIT sessions a week were found to be as effective as four 30-minute continuous exercise sessions at lowering blood pressure.

It can also reduce your risk of developing type 2 diabetes as it lowers blood sugar levels and studies suggest it may even be more effective at improving insulin resistance than continuous exercise.

5. It's over quickly!

Much as we love exercise, we love it even more when it's over. With HIIT you get the benefits in a short space of time, meaning it's easy to fit into a busy day.

What does a typical HIIT session look like?

HIIT sessions usually last between 20-45 minutes, including your warm up and cool down. That may seem short but it's because they're tough! During the main set, which can last as little as 10 minutes, you alternate between high-intensity exercises - think anything that gets your heart rate up, such as burpees or running on the spot - and periods of recovery.

In order to get results, the high-intensity intervals need to be performed at a full-on effort level. You should be working at a level of 9 out of 10 and struggling to catch your breath.

In a typical HIIT session you'll be working hard for 20 to 90 seconds at a time followed by a similarly short period of recovery to get your body prepped to go again.

These intervals can be scaled to your current fitness level. For example, you may want to start off with 20 seconds on, 20 seconds off and build up the duration you're working hard as you progress.

Where can I do it and do I need loads of equipment?

You can do a HIIT session pretty much anywhere and there's no need for any equipment. If you've only got a small space, like your living room for example, you can include heart-raising body weight exercises that don't take up much room, such as lunge jumps or high knees. You could even try running up stairs.

In a park you might want to add sprint intervals to make use of the extra space, whilst in the gym you could try doing intense 30-second intervals on a bike followed by 20 seconds rest or, for the more advanced, add in some dumbbells or kettlebells to help strengthen muscles.

If you're looking to get started with some HIIT training, why not give this beginner workout a try. The Beginner Plan in The Body Coach app is another great place to start your fitness journey.

Written by freelance writer, Kieran Alger.