In depth about cardio: HIIT and LISS, fasted and fed
cardio

In depth about cardio: HIIT and LISS, fasted and fed

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Today I want to talk to you about cardio; we have already discussed a few things about this cardio en what you should pay attention to with cardio. However, a number of questions have remained unanswered, such as whether doing fasted cardio actually makes more sense or not.

One claims yes, the other does not. There is certainly something to be said for both answers. After all, the total calorie deficit per day will be the same whether you are doing fasted cardio or not. On the other hand, if you don't have power in your system, where does the energy used come from when you do the cardio? At least partly from fat.

So who is right here?

In addition, discussions about HIIT versus LISS regularly flare up. In this article with its follow-up article I want to get to the bottom of this topic.

The dots on the i

What might be good to mention first is that anyway a calorie deficit is required for fat loss. However, as I mentioned in previous articles with you, it is important in this context in which time frame you view this story. Per hour? Per day? Weekly? I can bunk a lot 2 days a week and still be in a deep calorie deficit over the whole week.

Apart from the total calorie deficit, we can of course tweak and look for methods for maximum progression, but if the basis is not correct (the calorie deficit), the other tricks are of no use!

For exactly the same reason, such methods are of little interest to people who just want to lose some weight, just want to get fitter or just want to get some results. Do you belong to this group (where there is certainly nothing wrong with this) then this is not the article where you will see huge changes in your physical. Of course you are more than welcome to continue reading, but you prefer to focus on sufficient protein, sufficient healthy food, food that is well saturated and sufficient exercise.

However, do you want to squeeze that last bit of results out of your physical and training workouts and see how far you can get and are you willing to go the extra mile for that little bit extra? Then read on! In these 2 articles you will read how you not only optimally use your cardio for fat loss, but also for what it can serve even more.

cardio

What does science say about cardio?

Earlier I wrote an article about the problems with scientific research.

Research on training methods, diet methods or the effect of different types of cardio comes up against exactly these problems. Studies cost a lot of money, research groups are small, studies do not correct or bad for diet and other activities the rest of the day, studies do not correct for stress or inflammation etc.

It is absolutely good to keep scientific research as the basis of your approach and vision, but dare to look further and be critical. If a study says there is no difference between fasted or fed cardio, it doesn't necessarily always apply in all cases. If a study does not find a difference between HIIT or LISS, this does not mean that there is only a difference in energy consumption per time unit.

HIIT or not?

Another question I see a lot and get a lot is what better form of cardio is: HIIT or steady state (also known as LISS)?

Again context is very important in this story; first try to answer the question what the purpose of the cardio is and also what the context is in which the cardio is performed. HIIT will be more efficient per unit of time, but what about recovery capacity? How are your trainings built up at the moment? For example, HIIT has a greater effect on growth hormone production than steady state cardio, but if you're currently running a metabolic training block, the effect of HIIT will be proportionately smaller than if you're running a neuro block.

In the first case, adding HIIT may even cause inflammation through the overlap, especially if you are in the deeper stages of a cut. In this case, adding HIIT may have a completely different effect from what you are trying to achieve; recovery through the gutter, moisture retention through inflammation, deterioration in strength, fatigue build-up and excessive glycogen consumption.

At the beginning of a cut phase, recovery is often better and nutritional and carbohydrate intake is higher than at the end. This would mean that HIIT has potentially less negative effects here.

Because HIIT will put a lot more pressure on your recovery than LISS, it is wise to plan high intensity cardio earlier in the cut phase as described, but another shorter-term focus is where you plan your HIIT sessions during the week. If Tuesday is legday, a heavy HIIT session on Monday may not be wise. Furthermore, you can of course also make the choice to do concentric work as HIIT, such as pushing a sled or sprinting on a bicycle. This will limit muscle damage, potentially requiring less recovery.

Cardio

Fasted vs fed cardio

As mentioned, I want to delve a little further into fasted cardio versus fed cardio. People usually do their fasted cardio at low intensity.

As mentioned earlier in this article, according to studies, it makes little difference whether you do cardio fasted or not; the total energy shortage per day is all that matters. However, we have also briefly discussed the problems with research and we also know that when a research does not find an extra effect of a certain approach, this does not necessarily apply in all circumstances. The absence of clear results often means that if there are differences, these differences will not be large. If fasted cardio was really much better for fat loss, several studies had already demonstrated this.

'Compliance'

Do we already write off fasted cardio with that? No, not so fast. We are not dealing with robots or machines, but with people. Results are always hugely influenced by emotion; placebo effect is extremely strong in humans.

A perfectly written training schedule that remains in the closet will produce less good results than a '3/10 would not hit' schedule that you run neatly week after week. The most important thing for progress in terms of training and diet is to observe, maintain and work regularly. Compliance in English.

So let's say that if you prefer fasted cardio you should keep doing this. Because what I just said applies both ways; research does not show that fasted cardio is much better for fat loss, but certainly not much worse for muscle loss.

Optimize fasted cardio

A method that is sometimes followed because it would offer the best of both worlds is to take some protein or BCAAS and nothing else before you start your cardio. This would provide too little energy to complete the cardio, but would protect muscle mass from breakdown. However, I assume for the sake of convenience that you want to lose weight in this context. In that case, your glycogen stores are not fully filled and your liver may even be making glucose from amino acids. In that case, giving your liver another task will probably lead to more stress in the system.

Glycogen is very anti-catabolic and works well against muscle breakdown. In this context, it would be wiser to do your fasted cardio when the muscles that perform the cardio have at least some glycogen in stock and certainly the liver also has a reserve of glycogen. If you want to do fast cardio, taking some fruit before bedtime might be wise.

Cardio

Suppress the negative effects

We have now described a number of scenarios in which (more) cardio is counterproductive. However, we can certainly take steps to reduce these negative effects. I have already mentioned adding some fruit for bed. We can also take a few grams of BCAAS / EAAs during cardio and some fast carbohydrates to put stress on the system and limit the chance that the liver has to induce gluconeogenesis. However, nothing is free, not even these adjustments. The steps I describe here all cost a bit of space in your limited kcal budget, while you do the cardio to increase your calorie budget. So looking for a sweet spot between these 2 is important.

I think you now have a pretty complete picture of which forms of cardio and are in this article in combination with the 2 previous ones. We also looked at which factors you should take into account when you use HIIT cardio or prefer LISS cardio.

I want to write 1 more article to complete the story. Here I would like to discuss the further effects that cardio has on our body, how best to periodize cardio and which factors in life are important for the considerations you have to make in this area.

As always, you are more than welcome to ask questions.

This blog is written by

Jan Willem van der Klis

"My focus is on obtaining and disseminating the best possible knowledge to optimize training and nutrition"

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