What Is HIIT & What Are The Benefits?

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September 20, 2019

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We get it. Finding the time to work out can be hard. If you’re someone who is always on the go with work, family, or life in general, chances are you don’t want to commit to a lengthy daily workout. You’re looking for something fast, efficient but highly effective. That’s where high-intensity interval training (HIIT) can come into play.

HIIT has been a popular training style for years and is probably a fitness term you’ve heard of before or seen on social media, if it’s not a training style you’ve already tried yourself! 

HIIT isn’t easy, but we want to make it easy to understand. So, here’s everything you need to know to decide if HIIT is right for you at any stage of your fitness journey or when you’re choosing from the lineup of Sweat programs!

What is HIIT?

Designed to push you to your limits, high-intensity interval training is a popular training style for anyone who wants to push themselves and make significant progress towards their fitness goals with quick workouts.

This fast-paced style of movement will typically take you between 15-45 minutes per session and involves short, intense bursts of exercise, with brief rest periods in between each interval. Your rest period may involve a complete rest, or, if you have a higher fitness level or are looking to push yourself, it may be an active rest period that includes jogging or performing a boxer’s shuffle on the spot. 

HIIT workouts can be entirely bodyweight workouts or they can use a variety of weights for an extra challenge, such as kettlebells, dumbbells, medicine balls or barbells. What kind of exercises are we talking about? Anything that can get your heart rate up, such as squat jumps, mountain climbers, burpees, box jumps or medicine ball slams, to name a few. 

Any type of cardio exercise can be also done as a HIIT workout — including cycling, skipping, running or rowing. Simply set an interval timer and get started. 

Because the idea is to work at your maximum effort during each working interval, HIIT workouts will elevate your heart rate significantly and make you feel out of breath! If this feeling is new to you, it can be uncomfortable, but if you want to reap the benefits the aim is to push yourself every round to a level that feels challenging for you

According to the American Heart Association, vigorous activity is usually around 70-85% of your maximum heart rate, and you can calculate an estimate of your maximum heart rate by subtracting your age from 220.

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What are the benefits of HIIT?

Given how popular HIIT has become (it’s Head Trainer Kayla Itsines’ signature style for a reason!), it’s no surprise there are plenty of benefits to be gained from this vigorous training style. 

In a nutshell, HIIT can:

  • Increase VO2 max, cardiovascular fitness and stamina

  • Increase muscle mass and fast-twitch fibres

  • Increase speed, power, coordination and agility

  • Regulate glucose levels 

  • Improve bone health 

  • Improve mood and stress levels

  • Deliver you a challenging, fast-paced workout in a short period of time

Find out more below!

Increases VO2 max

HIIT works to improve your VO2max, which is the maximum rate at which your heart, lungs and muscles can effectively use oxygen during exercise. According to the University of Virginia’s School of Medicine, it is considered one of the best indicators of cardiorespiratory fitness.

A 2012 study on the effect of high-intensity interval training on cardiovascular function, VO2max, and muscular force found that even short-term bouts of HIIT (six sessions in total) dramatically improved VO2max in a test group of both men and women.

Increasing your VO2 max doesn’t only mean seeing a noticeable difference in your cardio fitness during your workouts, it means feeling fitter and more energetic in everyday life thanks to the overall improvement of your cardiovascular health.

Builds fast-twitch muscle

Fast-twitch muscle fibres are used in the explosive, powerful  movements you find in HIIT and are important to maintain strength and a healthy metabolism. Slow-twitch muscle fibres are used during low-resistance endurance exercise.

Everyone has a different ratio of fast and slow-twitch muscle fibres, but the National Academy of Sports Medicine says power athletes have a higher ratio of fast-twitch fibres, whereas endurance athletes have more slow-twitch fibres. 

According to the American Council on Exercise, including HIIT in your routine can help to engage and build your fast-twitch muscle fibres, helping to improve your performance during HIIT workouts, weight lifting, or forms of cardio that require a lot of power like sprinting.

Regulates blood glucose levels

A 2019 article published by the American Diabetes Association suggests that people suffering from pre-diabetes or type-2 diabetes may benefit from HIIT due to its effect on glycemic control. 

High-intensity training can help to regulate your appetite hormones by increasing glucose metabolism and insulin sensitivity, helping to regulate blood glucose at healthy levels. 

To ensure this training style is suitable for you, always follow the advice of your health professional. 

A more efficient form of cardio

If you’re short on time, HIIT can be a time-efficient way to work out as it challenges your body significantly in a short space of time.

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How are HIIT workouts structured?

There are plenty of HIIT programs from a variety of trainers in the Sweat app, and while they each follow different styles or structures, they all aim to give your whole body an intense workout!

Some of the most common high-intensity interval training styles include:


This training style means performing intervals of  20 seconds working at your maximum effort, followed by 10 seconds of rest for a certain number of rounds. Typically, a traditional Tabata workout involves completing eight rounds of each exercise, however, this may vary in different training programs.

Chontel Duncan includes Tabata training in her FIERCE and Full Body HIIT programs, which include six to eight exercises that you complete for two to four minutes each, separated by 40-60 second rest periods.

Cass Olholm’s Sweat programs High Intensity Strength at Home with Cass and High Intensity Strength with Cass also include full-body Tabata workouts.

If you’re new to fitness or coming back from a break, Samantha Ortiz-Young’s Low Impact HIIT and HIIT programs are great, beginner-friendly options which include Tabata-style training.


This stands for “as many reps/rounds as possible” where your aim is to repeat an exercise as many times as you can, or complete as many laps of a group of exercises as you can, in a given timeframe. The aim is to focus on speed and intensity to build fitness and endurance.

Chontel’s FIERCE and Full Body HIIT programs include AMRAP in the high-intensity resistance sessions — think exercises like burpees, sled push and box jumps

Cass' High Intensity Strength programs include Express AMRAP workouts, which are great when you're short on time, and Samantha’s HIIT programs include full-body AMRAP workouts.


This means “every minute on the minute,” and as the name suggests, you perform a specific number of reps of a certain exercise every time a new minute begins! 

If you finish your reps before the minute ends, the remaining time is your rest before starting again when the next minute begins.

Who can do HIIT?

The great thing about HIIT is that anyone with a base level of fitness and mobility can get started. However, like with any form of exercise, there is always a risk, especially if you are a HIIT beginner or push yourself too hard.

You can perform HIIT workouts with minimal space and zero equipment, or have fun using a wide range of equipment in a large space! Flexibility and efficiency are what make this training style so popular.

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How to get started with HIIT

When you start something as a beginner, like a new training style, you need to take steps to ensure your success. Here are some tips for getting started with HIIT.  

Always warm up

A good warm up before any workout is essential! Low-intensity aerobic exercise like a gentle jog or cycle is a great way to warm up, followed by some dynamic stretches to get your blood flowing and prepare your muscles for the movement to come.

Go at your own pace

If you’re new to HIIT, go at your own pace and listen to your body. If you have any prior injuries or health concerns or have never tried HIIT before, it’s best to get cleared by a health professional before getting started.

Focus on your form

It’s important to make sure your exercise technique is correct at every stage of your fitness journey, and the demonstration videos in the Sweat app are there to help guide you. Form always comes first! As your confidence grows, you can increase the intensity or try more challenging exercise variations.

If you begin to fatigue during a HIIT session reduce the intensity of the exercise so you are still able to complete each rep with proper form. This might mean using a lower weight, reducing the speed or number of reps, or switching to a less complex exercise. 

Fuel your workouts

HIIT requires a lot of energy, so being hydrated and having a pre-workout meal and a snack afterwards can power you through your session, help you avoid lightheadedness, and  promote muscle recovery after.

If you’re eating close to your workout, it’s best to have something light such as a banana or piece of toast. Experiment and see what works best for you!

Take the time to cool down

You should always end a tough HIIT session with a cool down, using stretching and foam rolling to focus on the muscles you have just trained.


RPE stands for “rate of perceived exertion”, or how hard an exercise feels. It’s a scale of 1-10 that you can use to determine your effort during exercise. 

A score of 10 indicates maximum effort. The work periods in a HIIT workout should be done at an RPE of 8. 

Make modifications when you need to

If you’re a beginner, a good place to start is with a 1:2 ratio. For example, do an exercise for a short period of time, say 30 seconds, then rest for one minute and repeat. As your fitness improves, transition onto a 1:1 ratio.

Focus on your own capabilities — not what others around you can do — and modify exercises or substitute movements where necessary. Several Sweat programs also have optional foundation or beginner weeks, which allow you to build confidence by starting with lower-intensity exercises. For example, you might start with stationary lunges, before progressing to reverse lunges and jump lunges as you get fitter and stronger.

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How to get more out of your HIIT workouts

Here are some workout tips to help you to get the most out of each HIIT session, and recover effectively afterwards.

Allow recovery time

The American College of Sports Medicine recommends spreading your HIIT workouts throughout the week to allow your body to recover properly. Low-intensity steady state cardio is a great way to keep your body moving in between workouts!

Foam rolling or active recovery can also help aid muscle recovery, too.

Short and sharp

There’s a reason the working intervals in HIIT are short - you shouldn’t be able to work at your max for very long, and giving it your all is the whole point of HIIT!

Use your rest breaks

Rest breaks during a HIIT workout allow your body to have short bursts of recovery to help you to work at full capacity during each high-intensity interval. 

By the time you finish your working interval, you should need your rest break to pause and have a breather before the next one begins. If you don’t need any rest, you may not be working at a high enough intensity.

HIIT alternatives

High-intensity training isn’t suitable for everyone because of how much strain it puts on your body, not to mention some people simply prefer other training styles

Strength training can help you to build lean muscle, challenge yourself and reach your fitness goals, without the high impact that HIIT can have.  

Low-intensity cardio is another great way to improve blood circulation, mobility and cardio health with less strain on your joints, ligaments and tendons.

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Ramp up your next workout with HIIT

HIIT workouts have so many benefits and there are so many ways to get started with this versatile training style in the Sweat app. Have you tried a HIIT workout yet?

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A more empowered you starts with Sweat, and our editorial team is here to bring you the latest fitness tips, trainer recommendations, wellbeing news, nutritional advice, nourishing recipes and free workouts.

* Disclaimer: This blog post is not intended to replace the advice of a medical professional. The above information should not be used to diagnose, treat, or prevent any disease or medical condition. Please consult your doctor before making any changes to your diet, sleep methods, daily activity, or fitness routine. Sweat assumes no responsibility for any personal injury or damage sustained by any recommendations, opinions, or advice given in this article.


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