While the popularity of high-intensity interval training (HIIT) might have reached new heights in the past few years it’s far from a new concept. Over 100 years ago Finnish runner Hannes Kolehmainen spiced up his training for the Olympics with interval runs, and hard-working Hannes was rewarded for his endeavours in the shape of gold in the 5,000m, 10,000m and cross-country events.
These days the term HIIT is used to describe a fairly wide range of training methods, which is why it’s not always clear what it is beyond the basics of work, rest, repeat. That description is not wrong, but it doesn’t get anywhere close to providing the full picture when it comes to what undertaking a HIIT workout actually involves.
Below you’ll find all the information you need on how to incorporate HIIT into your regular workout schedule, and how it can benefit you no matter what your overall goals are – whether you’re trying to lose weight, build lean muscle or knock a few seconds off your 5K PB. Crucially, you’ll also learn how often you should do HIIT workouts, because it’s not a style of training you should use every day – you’ll risk injury or burnout.
What Is A HIIT Workout?
While “hard work, short rests” is the essence of a HIIT workout, there are five main variables that can change the nature of your session massively. The first two are your work and rest durations. Working for 40 seconds and resting for 20 is significantly different to resting for 40 and working for 20, with longer work periods generally being better for improving endurance and shorter ones better for power.
Then there’s the intensity of the work periods. With HIIT you need to be pushing hard to get the most benefit from it, and it’s also important to try and maintain a consistent level of effort across the work periods. That means it’s not just about going all-out, because you won’t be able to sustain it across the HIIT workout.
“You need to know your target heart rate or understand the rating of perceived exertion (RPE),” says Philippe Ndongmo, a personal trainer at Dolphin Square Fitness Club in London. Rate the latter out of ten and try to keep the effort constant across every interval.
The fourth variable is the type of rest you do – are you stopping completely or engaging in active recovery, like pedalling slowly on an exercise bike? The latter can help flush out lactic acid ahead of your next work period.
Lastly there’s total volume, as in how many intervals you do. It’s easy to do too much with HIIT, which ends up being of no real benefit because by the end of the workout you’re unable to maintain the intensity. As a rule, start with low volume and go as hard as possible. When it feels easy, add a round or two, but drop the RPE slightly.
That’s just about it. There aren’t any hard and fast rules when it comes to HIIT workouts in terms of the type of exercise you do. they can be done with bodyweight exercises, cycling, running or weights, just as long as you’re able to do it at a high intensity. That makes some disciplines more suitable than others. Rattling out efforts on an exercise bike is significantly less dangerous than trying to do heavy barbell squats at a furious pace (please don’t do heavy barbell squats at a furious pace).
You can cycle through a circuit of different exercises for your HIIT session, or stick to one or two for all of your reps. The latter makes it easy to hit your time targets because you don’t have to switch exercise equipment during your rest periods, but doing a circuit containing a variety of moves means you can target more muscle groups during your workout.
The Benefits Of HIIT Workouts
Let’s start with the calories you’ll burn, which are many, not only during the HIIT workout but also in the hours afterwards. The latter comes from the excess post-exercise oxygen consumption (EPOC) effect, where your body burns more calories as it returns to its normal resting state after a workout and adapts to the exercise you’ve done. The EPOC effect increases with the intensity of the exercise you do, which is why HIIT is such an effective fat burner.
HIIT also increases your VO2 max, which is the amount of oxygen your body can use and is an indicator of cardio fitness. This is why any cycling or running training plan worth its salt has some form of interval training in it. Increasing your VO2 max is key to working harder for longer, helping you log a 5K personal best, for example.
There are also logistical benefits to HIIT, like the fact your workout takes less time so you can fit it into a lunch break. And while it’s tremendously hard work, the short, sharp challenge of HIIT ensures you’ll never get bored with your training.
When To Avoid High-Intensity Workouts
If you’re feeling worn down in the first place, HIIT isn’t the session to go for. “A common mistake with HIIT is the assumption that it trumps steady-state cardio at all times, which isn’t true,” says David Jordan from personal training gym The Fitting Rooms.
“HIIT is highly effective because it requires less time and burns calories during recovery. However, to reap the benefits of HIIT you need to attack it with a lot of energy. On days when you’re feeling less than 100% or, more importantly, you’re sore from your previous workout and are at risk of pulling a muscle, then steady-state cardio is probably more effective – and safer.”
Finally, it’s important to consider how often you can do “real” HIIT. “It’s true that HIIT can trigger protein synthesis but it also causes protein breakdown,” says Jordan. “Doing several HIIT sessions a week would be catabolic so while you’d lose weight overall, some of that loss would be muscle mass.
“If building muscle is a goal, proper weight training still needs to be your primary focus with HIIT as a supplement. A training split of two weights sessions and two HIIT a sessions a week would keep you lean, while making sure you aren’t overtrained.”
Remember: it’s supposed to be short, intense and infrequent, not an everyday effort. Recovery days are vital both for avoiding injury and for ensuring you can actually work at the intensity required for effective HIIT. Simply put, if you’re doing four or five HIIT sessions a week, it probably isn’t real HIIT, and you’re probably going to get injured.
Types Of HIIT Workouts
Beginner: Timmons method
Developed by a team at Loughborough University, this HIIT workout is entry-level. Do 20 seconds of all-out work, followed by two minutes of active recovery (walking/freewheeling will do) or complete rest. Repeat three times, and you’re done.
Also known as “reverse Tabata”, this HIIT workout doubles the rest and reduces the work intervals to shift the focus to anaerobic fitness. Use it if you’re aiming for power production, or if you don’t have the fitness for an all-out Tabata (explained below). Warm up for 10 minutes, then do six to eight rounds on a cardio machine.
Now things get complicated. In this plan, you’ll do five “blocks” of work, made up of 30 seconds at 30% intensity, 20 seconds at 60% and ten seconds all-out. Result? Lots of volume, at manageable intensity.
The most famous HIIT workout protocol is ideal for increasing VO2 max – as long as you do it right. Twenty seconds of all-out work, followed by ten seconds of rest, repeated eight times, improved endurance by as much as 30 minutes of steady-state cardio in a Queen’s University study. The key is keeping intensity high – if you can talk during the session, you’re getting it wrong.
7 HIIT Workouts To Try
1. Kettlebell HIIT workout For Fat Loss
A Louisiana University study that compared kettlebell swings, cleans and deadlifts with a more traditional sprint training programme found that maximum heart rate was only slightly higher in the sprints, while calorie expenditure was bigger with the bells.
Here’s one of our favourite circuits. Rest for 30 seconds at the end, then repeat for three to five rounds.
- Alternating swing (30sec) Similar to the traditional swing but alternating arms at the top portion of the lift.
- Clean and jerk (15sec left arm, 15sec right arm) Finish each 15-second work block by pressing the kettlebell over your head.
- Goblet squat (30sec) Hold the kettlebell close to your chest and keep your back straight.
2. All-Out Exercise Bike HIIT Workout
There’s a reason lots of studies use exercise bikes: going all-out on the pedals isn’t too technical, injury risk is low and you can ruin yourself. For “supramaximal” efforts, which stimulate every available muscle fibre, the bike is the perfect choice.
When looking to improve the fitness levels of Premier League footballers in pre-season, strength and conditioning coaches at the country’s top clubs have a particular favourite in the Tabata protocol. It’s used up to four times a week and typically performed on an exercise bike. You can reap the same rewards by following the plan: 20 seconds sprint cycle; ten seconds rest or slower cycle; repeat for eight rounds.
3. Battle Ropes HIIT Workout For An All-Day Burn
In a College of New Jersey study, battle rope exercises beat 13 other exercises (including burpees) for energy expenditure and produced the highest average heart rate. The protocol: 15 seconds of single-arm waves, 15 seconds of double-arm waves, 60 seconds’ rest, repeated eight times.
4. Burpee HIIT Workout To Improve Endurance
In the same New Jersey study, burpees beat four other bodyweight moves and every free weights exercise for VO2 response. If you’re short on time and space, use the Wingate protocol: 30 seconds all-out, then four minutes of rest, done four to six times.
5. Sprint Workout To Increase Power
“Production training” workouts improve your ability to work at maximum effort with short rest. They are ultra-short, super-hard exercise intervals combined with long rests for a workout that’ll improve your power. Use them when you’re chasing a 500m row PB or preparing for a boxing bout.
1 Mountain slider
Work 15sec Rest 1min 30sec Rounds 6
Start in a press-up position with your feet on a pair of small towels or Valslides, then bring one knee and then the other up to your chest as fast as possible. Think of it like a crawling sprint.
Work 15sec Rest 1min 15sec Rounds 6
Holding a light pair of dumbbells at shoulder height or a light barbell on your shoulders, drop into a squat. As you stand up, drive the weight overhead, then lower straight into the next rep.
6. Endurance HIIT Workout To Improve Your 5K Time
“Maintenance training” workouts use longer work intervals and slightly shorter rests to increase your body’s ability to sustain exercise at high intensity, using both your aerobic and anaerobic systems.
Work 30sec Rest 1min 30sec Rounds 6
Using a moderate-weight kettlebell, swing it back between your legs and then pop your hips forwards to swing it to eye level, letting it drop straight into the next rep.
2 Assault AirBike
Work 15sec Rest 45sec Rounds 10
The Assault AirBike forces you to use your full body for a short-but-nasty experience. Haven’t got one? A regular exercise bike also works.
7. HIIT Workout To Get Lean In Your Lunch Break
Shortening the rests and keeping the work rate high burns more calories during and after your workout, for maximum fat loss. This session from Ndongmo will get you lean in your lunch break. Do all three exercises to complete one round, and repeat eight times.
Work 20sec Rest 10sec
Explode off the ground and change legs in the air on each rep. Rest for 10 seconds, then go straight into exercise 2.
2 High knees
Work 20sec Rest 10sec
Run on the spot, bringing your knees as high as possible. Keep the intensity high throughout, then rest for ten seconds.
Work 20sec Rest 30sec
Drop into a squat and then explode off the floor, landing as softly as possible. Rest for 30 seconds before you start the next round.
More HIIT Workout Ideas
Joe Wicks’ Four-Week Fat Loss Workout
Everyone’s favourite HIIT evangelist provided us with an exclusive four-week workout plan which contains four bodyweight HIIT sessions per week. Each workout is made up of five moves and takes around 15 minutes, so they can fit into even the busiest of schedules. See the Joe Wicks workout
HIIT Workout With Weights
You’ll need a kettlebell, dumbbells and a weight plate for this testing 15-minute session, which consists of three supersets of compound exercises that work muscles all over the body. See the HIIT workout with weights
10-Minute HIIT Workouts
One of the best things about HIIT is that you get an effective workout done in less time, as evidenced by these 10-minute sessions. Check out our collection of 10-minute workouts which target different body areas using a variety of equipment. See the 10-minute workouts
20-Minute HIIT Workout
The Tabata method is a HIIT classic and this quick bodyweight workout will show you exactly why it’s so effective. Not only is it great for your fitness, it also helps to relieve stress as you power through the short work periods. See the 20-minute HIIT workout
30-Minute HIIT Circuit
This 30-minute circuit was put together by the functional fitness experts at F45. The workout involves three rounds of nine exercises, and you’ll need dumbbells and a kettlebell to do it. See the full-body HIIT workout
Rowing HIIT Workout
The rowing machine is one of the best bits of equipment to use for HIIT, because it fires up a wide range of muscles and will spike your heart rate rapidly. This workout involves all-out efforts on the rower broken up by weighted exercise circuits – you’ll need dumbbells, a kettlebell and a medicine ball. See the rowing HIIT workout
HIIT Boxing Workout
Few exercises will tire out as quickly as whaling on a punching bag, and this quick workout combines that with bodyweight moves used by MMA fighters to raise your heart rate sky high. See the HIIT boxing workout
HIIT Conditioning Workout For Runners
This bodyweight HIIT workout is specifically designed to meet the needs of runners aiming to build strength to cope with the demands of the sport. It can be done anywhere you have room to sprint 150m. See the HIIT workout for runners
Outdoor HIIT Workout
Head to your local green space for this 30-minute workout made up of five bodyweight exercises. You don’t need any equipment, but you’ll be doing 10m shuttle runs so will need to mark out that distance. See the outdoor HIIT workout
Strength And Sprints HIIT Workout
Created by a trainer from boutique gym Sweat It, this workout consists of two sections: one based around compound strength exercises and the other done on the treadmill. It takes less than 30 minutes to do, including a proper warm-up. See the strength and sprints HIIT workout
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From 2008 to 2018, Joel worked for Men's Fitness, which predated, and then shared a website with, Coach. Though he spent years running the hills of Bath, he’s since ditched his trainers for a succession of Converse high-tops, since they’re better suited to his love of pulling vans, lifting cars, and hefting logs in a succession of strongman competitions.