Guest Post - 'HIIT, LISS or MISS?' By Dan Osman

The controversy and the discussion surrounding the concepts of HIIT, LISS and MISS, in terms of health, body composition and performance, is eternal! So at risk of starting a mass debate, I’ll begin by stating that the benefits of each very much DEPENDS on the individual’s goals, and, as with any other aspects of the human body, no one size fits all - vague…I know!

What are HIIT, MISS and LISS?

First off, let’s categorize these different modes of cardiovascular activity:

LISS - Low Intensity Steady State
MISS - Medium Intensity Steady State
HIIT - High Intensity Interval Training

In my opinion, confusion often lies in the terms LISS and MISS (sometimes HIIT also), with individuals using the acronyms interchangeably within written articles. Personally, LISS is simply ‘energy burning’ (I don’t even refer to this as ‘cardio’) and in terms of competition preparation, an effective tool for burning additional energy to further a caloric deficit towards fat loss, and a good substitute in contrast to lowering my food intake, which would otherwise potentially place my body under additional stress. For example, a power walk, or a brisk stroll could be considered as a LISS activity.

However, I’ve often found that those referring to their ‘cardio’ as ‘LISS,’ are actually performing ‘MISS’, which is great if increasing performance is your ultimate goal, but in terms of body composition, can potentially hinder fat loss goals, muscle retention and encourage catabolism (the breaking down of the body), not to mention contributing to injury, when performed in EXCESS.

The same can be said for HIIT; how many of you have seen your favourite physique athlete tweet “just smashed one hour of HIIT training” - Surely if you’re performing true HIIT, at the highest possible intensity your body is capable of, you wouldn’t be able to maintain this for an hour??? Again, they are most likely performing interval based MISS - Confusing, right???

I’m confused just reading that back.

My main point here being; it is all very subjective and again very different depending on the individual’s goal(s)!

In all honesty, I started writing what I had planned to be a short, general ‘HIIT VS LISS’ advice piece………

The truth is, the thought of it bored me! It’s a highly complex and involved subject, which by far surpasses most of what I will refer to in this post, and often only ever results in “further research needed.” Also, how many fitness articles have you already read on this subject?! Lots, I’m guessing, especially if you’ve now taken the time to kindly read mine - thanks in advance! I’ll try not to make it something you choose to read before bed.

So, which one should you use?

Facebook, twitter, community forums, your favourite athlete pages, websites, peer reviewed journals, etc. are flooded with opinion and research-based ‘absolutes’ and  what’s ‘right and wrong’ - It’s no wonder the general population are confused with the amount of information out there!

Generally speaking, I found success with all modes, both personally and with clients over the years. Whatever their goal, be it health, fitness, body composition or performance based, the conclusion I’ve arrived at with HIIT, MISS amd LISS - as with most things relating to the human body - no one size fits all and they all work! (How many of you could see that coming?!)

In all honesty, have we been MISSing (see what I did there?) the point…..???

For some, ‘cardio’ is the ‘go to’ when it comes to losing weight (and when we refer to weight, would you agree that we’re actually more concerned with body fat?), whilst for others in the fitness industry, with reference to LISS and MISS, and sometimes HIIT, the word ‘cardio’ is often demonized as ‘muscle wasting’ and detrimental to body composition goals.

What is truly important to me, in order to gain a better understanding of what my clients want to achieve, is the context in which ‘cardio’ is used, their own personal end goal, and probably the most astute from a coach’s perspective - adherence.

Typically, for those with body composition/weight loss/fat loss goals, however you want to term it, the mode in which they undertake their additional ‘energy burning’ or ‘cardio,’ and the differences between, them is marginal.

What are they likely to enjoy doing? What are they likely to continue doing?

Often ‘HIIT’ is termed as the ‘gold standard’ of fat loss, based on the premise surrounding the subsequent effects of EPOC (Exercise Post Oxygen Consumption) and the subsequent calories one ‘burns’ after a bout of HIIT – but are these substantial?? Not really.

What has been demonstrated is that individuals performing HIIT are more likely to consume more food post-exercise, in an effort to feel more satiated because they’ve worked harder. That is, if the subsequent effects of EPOC ‘burns’ an additional 20-30 calories, only for the individual to then consume an additional 100 calories more than they would performing LISS, doesn’t this completely negate their original intent??  Perhaps for that individual, LISS would have been a better option.

What if your goals are also performance based, such as football, rowing or rugby? Your body relies on a certain amount of stored muscle glycogen, which in its simplest form, is derived from carbohydrates, for performance based activity. Yes, HITT does have its place in relation to fat loss, but ultimately, if your goals are performance based and your muscles are constantly depleted from HIIT training five days per week, this WILL result in a decline in performance!

A few truths about body fat and fat loss

Adipocytes (fat cells) are with you for life! Even the extra’s we accumulate over our lifespan stick around and only in extreme circumstances (including cosmetic surgery) is it possible to completely eradicate them.

To steal a nice little analogy from another practitioner - they are like balloons. They will deflate over time but are also quite easily ‘refilled’ through lifestyle choices. If you’ve ever been overweight (as I have) or know others that have - notice how quickly they can gain weight again?

Fat is ESSENTIAL in dietary terms. With regard to storing energy, dietary fat actually yields more usable energy than any other macronutrient. Unfortunately though, because of the associated health consequences related to being obese, dietary fats have been demonized (although I will acknowledge that the general public is now swaying away from ‘fat free’ products) in international press.

Even from an athletic standpoint - does it serve a rugby prop to be super lean?? Absolutely not. In this example, a little bit of extra body fat can act to cushion the blows of some of the mass trauma placed on the body during a game.

There is no such thing as ‘fat burning’ foods

Overconsumption of fat WILL make you fat, just as the overconsumption of protein or carbohydrates will also cause you to gain weight – calories DO count.

Whether it’s a low carbohydrate diet you are following, or just the overconsumption of any nutrient, ultimately, a surplus of calories over a prolonged period, WILL increase body mass and body fat, too. In its simplest form; surplus = gain, deficit = loss.

There are many other factors that come into this, such as the “is a calorie a calorie” argument, the difference in absorption rates, and the ‘types’ of calories, but that’s another story entirely. Energy balance should be the foundation to any weight loss/gain plan.

Hit a sticking point? Try a different ‘mode’ of exercise, e.g. if you’re typically a runner, attempt rowing.

If you’re on a low carbohydrate diet, protein and fat intake may need to be increased to prevent protein degradation and enhance recovery. To this effect, you may have previously read about the addition of BCAA’s (Branched Chain Amino Acid’s) or EAA’s (Essential Amino Acid’s) for semi fasted cardio sessions.

Putting the Osman into Bossman!

To Conclude

Reading back on my post, I can see I’ve failed MISERABLY……… ‘Short and succinct’ it is not! But hopefully it interested some of you.

Now, this post is in no way, shape or form intended to ‘preach’ about the right or wrong way to perform cardiovascular exercise. I’ve certainly advised and used protocols in the past that I no longer agree with, and have used a mixture over the years to achieve the same results.

They are simply tools, and in my opinion all have their place.

Is one better than the others? Depends! Vague, again!

If anything, I hope that some of the above makes you question ’WHY’ you’ve chosen, or are choosing, the method you have. There is no right or wrong answer, but unfortunately we live in a society of ‘absolutes’ - the fitness industry in particular is guilty of this. Surely one is ‘better’ than the other, or right or wrong???......... Depends!

Is a 10km run three times per week ‘optimal’ for fat loss (what is optimal anyway???) - Probably not, but will it contribute to fat loss? Yes!

If you enjoy doing something, stick with it! From a coach’s perspective, if you would rather do a particular activity, over a vomit inducing 15-minute HITT session, which you’re likely to dread, and potentially skip entirely long term, then it’s a ‘no brainer’ for me. Long term adherence, and ultimately RESULTS, is what I’m interested in.

About Dan:

Dan Osman is an experienced personal trainer, and strength and conditioning coach. He's the founder of ACE Performance, and perhaps most importantly, a member of the Be An Athlete Ambassador Squad. 

He is focussed about getting results for his clients and combines a down to earth approach with an unprecedented and asserting passion for health, fitness, nutrition and performance.

Image Credits:

Title - Matt Marsh Photography
Image 1 - Rebecca Andrews Photography
Image 2 - Matt Marsh Photography


  1. Hi Dan

    Love the post, there are some interesting points there Your right the whole topic is a confusing one. As a convert to HIIT (if indeed that is what I have been doing!) I have seen and felt the benefits already. I've also read good evidence that your less likely to over eat in compensation after HIIT rather than after cardio. The debate goes on! I think th key thing as in life is a little of everything, mix up some cardio with some HIIT for the greatest benefits to mind and body.

  2. To make your body function in the right way and to look young even in the older age, effective workouts are highly needed. I too have been thinking to join the yoga sessions soon but will need some good quality apparels and shoes. Will buy the shoes from Nike but for the apparels, I need some reviews about the brand Alo Yoga. Can you share that?

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