Doesn’t getting your exercise for the day done in 20 minutes sound enticing?
Quick workouts ranks as a key reason why HIIT (high-intensity interval training) workouts have become so popular, but it has also contributed to myths about just how effective they are.
It’s unsurprising to hear people making ludicrous claims in the health and fitness market (this is pretty common, I’m sure you’ve noticed!), but we’re all about clarity and real evidence. If you like no-nonsense fitness advice, buckle up: today we’re going to take you through the real benefits of HIIT and provide some insight on how it can help you, but also clear up some misconceptions and do some serious myth-busting.
What is HIIT?
HIIT is a type of exercise that alternates between high- and low-intensity intervals of the same exercise. This might mean alternating between sprints and jogging, for example, to keep your overall intensity high without burning out.
HIIT is a common practice now, with countless variations and personal styles, from CrossFit to military-style training to sport-specific conditioning. You can find a “revolutionary” approach to HIIT in almost every gym, but the principles and evidence are key – this isn’t about your favorite exercise class.
HIIT’s Reputation and Myths
HIIT deserves a good reputation, but it has been billed as the best or only way to lose weight effectively, which is simply untrue. The primacy of HIIT over other forms of exercise like low-intensity steady-state (and everything between the two) has run rampant through the exercise science world, and has been misinterpreted by personal trainers and countless blog/article writers.
HIIT and Weight Loss
The first thing worth noting is that HIIT burns fat the same way any other form of exercise does: it uses a certain amount of energy (measured in calories), increasing your energy deficit . This forces your body to cover this calorie short-fall by using fat stores (either directly or indirectly). This is the same way that LISS (low-intensity steady state) or your mom’s Zumba class burns fat.
There has been a lot of talk about how HIIT has higher EPOC (excess post-exercise oxygen consumption – the number of calories you burn after working out), which might make it more effective. However, studies suggest that there is no significant long-term benefit to HIIT over lower-intensity, higher-duration exercise, and that HIIT’s EPOC level is less promising than originally thought .
Additionally, if EPOC is the main reason to favor HIIT over other forms of exercise, heavy weight training would be the best choice – it has even greater EPOC than HIIT and builds far more muscle, strength, and power.
The main benefits to HIIT for the general population is time-efficiency. Most people don’t exercise enough because they’re short on time. This a great context for HIIT, but doesn’t make it a superior form of exercise in terms of effectiveness.
HIIT and Endurance
The literature on HIIT versus continuous cardio exercise has been relatively unenlightening on the way that the two compare and which is “better,” but they do provide interesting insights into their differences.
HIIT has been shown to have no greater or lesser effect than continuous cardio in the mid-term, despite taking up less time. This sounds like a positive, but it reinforces the fact that they are the same: you might be able to perform the same results with 20 minutes instead of 60 minutes, but with 300% more effort. The differences are purely logistical.
The real differences are the physiological adaptations that each style of training brings about , and the way that they should be added into your workout routine or training program (depending on your goals) as a result. HIIT contributes to increased stroke length, the amount of blood your heart pumps with a single beat, and VO2 max – or volume of maximum oxygen that your body can utilize – one of the best predictors of overall endurance and health. Other metrics suggested very little difference (such as heart chamber adaptations and resting heart rate).
What does this mean for you?
If you’re a casual gym-goer, it probably means that you should be doing both. You don’t need to worry about excessive specificity or focusing on a particular type of adaptation. Your health and fitness won’t be affected by which one you use. For an athlete, HIIT should be a key part of a foundational block of training, and should make up the majority of a power athlete’s conditioning work (especially when used with loaded exercise like sled pushes).
HIIT and Time-Efficiency
As mentioned above, HIIT solves one of the most common health and fitness problems for the general population: it takes up very little time and combines a number of key methodologies that can be used to improve everything from strength and power to endurance and co-ordination.
It is important to note that this is a genuine benefit in a practical sense, but this only makes HIIT superior in-context. For those athletes who are willing to commit a few hours a day to exercise, this isn’t a deciding factor. LISS and other forms of cardio have their own key benefits that might be worth the extra time: it is easier to do, can be performed while enjoying other media (long cycles with a podcast, for example), and preferentially targets visceral fat.
When you’re weighing up HIIT and other forms of conditioning, be sure to refer to your own needs and circumstances. There is no best form of cardio or conditioning other than in the context of your own goals and situation. If you’re a busy executive with kids, perhaps HIIT is for the best, but if you’re searching for optimal health improvements, it might not be.
HIIT and Athletic Qualities
One of the best reasons to implement HIIT into your training is to gain some of the secondary effects beyond fat loss or endurance. While the drawbacks of HIIT are context-sensitive, so are the benefits – some individuals should always opt for HIIT!
HIIT is the superior form of conditioning work for an athlete in a power and strength sport – this is uncontentious. An Olympic weightlifter or thrower is not interested in their ability to run a 10km with a consistent pace, but with their ability to apply force instantaneously. These athletes need to recover between attempts and develop good conditioning, but endurance exercise won’t contribute to power, but the opposite .
For example, a HIIT session involving sprints/jogs and kettlebell swings/rest is going to contribute to the development of strength, power, co-ordination and posture that an exercise bike simply can’t. HIIT can be used to great effect if you take some time to think about the exercises you’re using and the traits that they will develop.
It might not be the best/only way of training, but HIIT can be the best for your needs if your needs are short bursts of power or adding new elements to your training that don’t get enough attention otherwise.
HIIT: Key Risks and Dangers
HIIT is great for your health, but you have to approach it properly and ensure you’re prepared. This means choosing the correct exercise and load for your abilities, being honest with yourself about your abilities, and taking proper warm-up precautions.
Because HIIT includes high-intensity exercise and rapidly changing pace between high-intensity and low-intensity, there’s a large injury risk. This is particularly pronounced for movements like sprints and heavily-weighted exercise, so be sure to warm up thoroughly and target problem areas (such as the shoulders, hips and ankles).
Warm up first
Be sure to involve LISS (low-intensity steady state) and other forms of gentler movement to warm your body up and scale up to your high-intensity intervals so you’re prepared . Cold sprints have damaged many ankles and HIIT should be performed by those with a moderate experience level in their chosen exercises and training in general.
How can you Make HIIT Work for you?
The problem with learning about HIIT (and writing about it!) is that it is a methodology rather an a set of exercises. There are many different styles out there which have their own key exercises, but there’s no essential exercise. It’s like explaining the difference between a Todorov narrative and writing a novel!
If you’re looking to add HIIT to your training or re-arrange your existing training to make the most of it, here are a few simple tips that you should think about before moving forward.
Put your life/schedule first
German Philosopher Immanuel Kant once said that ‘ought implies can’. This is important: you should only worry about what you can do. If you have 45 minutes to cover your whole session, HIIT is going to play a big part in your workout: you might want to include a single key strength movement (like the squat) followed by a HIIT circuit that includes other strength and power movements (like an upper-body pressing movement and sprints).
Keep your goals in mind
Your goals will determine what you should do – if you want to ever achieve them, anyway! If you’re training for power sports you’ll find extra benefits in performing power-based HIIT, whereas a marathon runner should aim at LISS and huge long-term endurance.
Similarly, if you’re aiming to improve your health you should focus on the health-promoting effects of traditional cardio, or at least combine the two approaches. The general population, or those who are looking to burn fat, are unlikely to ever notice a difference in terms of results!
Be sure to work on your weaknesses
HIIT is a great opportunity to work in some of the areas of training you might neglect most: rows, core, and carries, as well as moving in the lateral, unilateral and transverse plane. This is a simple way to bunch together all the exercises you hate and avoid (I know you do), getting them all out of the way at the same time and improving your endurance along the way.
Keep your intensity HIGH
HIIT requires you to actually put in serious effort during your high-intensity intervals. This means anywhere between 85 and 100% effort everytime. If you’re looking to turn up and make progress in a short space of time but you’re not going to push yourself during these intervals, you may as well not bother. The point of HIIT is that it provides you with a great way of saving time by putting in more effort: it isn’t a short-cut or excuse.
Closing Remarks
HIIT is a great choice and, in some circumstances, it might even be the best choice – but this isn’t always the case, and it is important to consider the context and your overall goals for health and fitness. If you’re looking to make serious progress but have limited time or need to develop specific short-duration abilities, HIIT is a great choice.
Key Resources
Exercise description/explanation:
Exrx.net provides free, impartial descriptions and demonstrations of exercises as well as their muscular demands and other key information.
Eric Cressey provides top-level S&C advice and advanced exercise instruction for hundreds of excellent movements that provide balance and joint health.
Gymnastic and core exercises: GymnasticBodies is the definitive source for core and mobility work – both of which are important to health and a balanced physique.
Tabata Protocols: Tabata Songs provides hundreds of videos of Tabata-based HIIT training across different methodologies, including CrossFit .
You can also find some great resources on social media, such as Rob Coles’ SeriousAboutStrength account.
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