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  • Writer's pictureHarry Chamas

KAATSU for Freediving | The Future of Freedive Training

Updated: Aug 20, 2019

I was lead to KAATSU by a simple problem, I was no longer able to sustainably train lactate in the pool due to my technique and strength being at a level that meant it was very difficult to build acidity in the muscles, and training it in the gym required heavy weight and high repetitions (70kg for 30 reps)

So I began to wonder if it was possible to restrict the blood flow to the legs in order to gain an early onset of lactate build up. It turned out that not only is it possible, but there is a wealth of research about it, all of which is very positive and promising. Not only that, but the benefits go far beyond lactate tolerance.

The more research I did, the more convinced I became about the potential of this type of training with regards to freediving.

So without further a do - let's get stuck into what KAATSU is all about.

What is KAATSU?

KAATSU also called BFR (blood flow restriction) is a form of physical training that uses arterial blood flow restriction in conjunction with light exercise to cause a series of positive physiological effects.

The father of the concept is Yoshiaki Sato who began research as far back as 1966. Since then the method has been used in rehabilitation, physiotherapy for the elderly and athletic performance.

How does it work?

By restricting the venous (de-oxygenated) blood flow out of the muscles - without restricting the Arterial (oxygenated) blood and performing appropriate exercise at a low intensity, KAATSU causes an accumulation of waste products and a swelling of blood vessels within the chosen body part.

This swelling and build up of waste causes a disturbance in homoeostasis and the nervous system reacts by secreting HGH (human growth hormone) and NO (nitric oxide). The sympathetic nervous system is stimulated to make the muscle bigger and stronger.


How is this beneficial for freediving?

Fasten your seatbelts!

Lactate tolerance

Lactate training has long been a staple of freediving, this can be done dry or in the water - on breath hold or not. It requires exercising at a close to maximum intensity for long enough to cause a burning in the muscles or muscular failure.

Training at this intensity is taxing on both the athletes mind, body and the CNS (central nervous system).

KAATSU allows a build up Lactate in the muscles without the athlete needing to perform at high intensity, as little as 20% of a 1RM (1 rep maximum) is needed to create a disproportionate build up of acidity in the muscles.

This means you can train your bodies ability to buffer lactate without long breath holds, heavy weights or super strenuous exercise - reducing the chance of over training.

Not only this but the build up of acidity in the muscles is insane! I have trained my whole life in various sports, and nothing compares to this burn. The muscles continue to burn even during the rest period, standing submerged up to my neck in the pool is strenuous! If training Lactate is a priority for you, this is a amazing way to do just that.

Less chance of over training

Training at a high intensity is a tax on the mind, body and CNS (central nervous system).

Long/tough breath holds, Strength training, Lactate training, HIIT and of course deep diving all have a heavy toll.

The speed we can recover from this toll dictates how much we can train and whether or not we will become over trained. Essentially the more we do, the more time we need to recover, and conversely, the quicker we recover, the more we can do and the more adaptations will occur.

For this reason, if there is a way to train any aspect of freediving with less stress to the body and mind, we have potential to train more/recover faster.

KAATSU allows us to do just that!

Light work load means less (almost no) damage to the muscles and tendons, this means the body becomes stronger without first having to repair itself (previously not thought possible) saving recovery time.

The workouts usually last under 10 minutes, this means if strength/lactic is not a priority, it is possible to maintain/build these sides of freediving very quickly allowing more time and energy to be focused on other training.

Lactic training and strength training in the pool can be done on apnea without challenging breath holds, making the training less mentally stressful and less likely to lead to over training.

Quicker recovery times

As previously mentioned, the low damage done to the muscles allows for quicker recovery. But there are several responses to KAATSU that will also aid with recovery...

Raised HGH (human growth hormone) - HGH is responsible for triggering the muscles to become bigger and stronger, levels have been see to rise 290% following KAATSU.

Increased NO (nitric oxide) production - NO has a wide array of benefits to the body, including being an anti oxidant, aiding Intra-cellular communication, improving blood circulation, and strengthening the immune system.

Improved protein synthesis - Raised HGH and IGF-1. We can think of protein as the building blocks of the body, KAATSU triggers elevated levels of HGH and IGF-1 which in turn signal the body to utilize protein to build and repair.

Increase in strength

Studies have show without a doubt that KAATSU increases maximal strength while still performing at low intensity (20-30% of 1RM). As much as an 8% increase in maximal strength have been seen in trained American football players after just 4 weeks of KAATSU, a 3% higher increase than the control group.

This is possible because KAATSU quickly depletes type 1 (slow twitch) muscle fibres, to continue to perform - type 2 (fast twitch) muscle fibres are recruited. These muscle fibres are responsible for strength and explosive power, they are usually difficult to train and require a very high intensity causing muscle break down.

Since KAATSU is able to train these fibers, they are stimulated to grow and you become stronger.

Type 2 muscle growth

Type 2 muscle fibres operate without oxygen. They are recruited at times the work load is too intense to be sustained aerobically or in a situation that there is not enough oxygen delivery to the muscles, such as after peripheral vasoconstriction or KAATSU.

In order to train and build type 2 muscle fibres, the intensity of exercise must normally be very high, such as heavy weight lifting and sprints.

Because the oxygen in the muscles is quickly depleted with KAATSU, type 1 muscle fibres become exhausted and type 2 muscle fibres are recruited to continue the exercise.

Without KAATSU we need to be operating at above 70% of our maximal strength to create these adaptations, with KAATSU we only need to be lifting 20% of our max.

This means we get some great training with less tax on the system as a whole.

Proven cross over into the water

Studies have shown that the increase in strength and ability to buffer lactate gained from KAATSU swimming drills have lead to increased speed and stamina in swimming sprints and repetitions in experienced swimmers.

Myoglobin increase

Myoglobin is where oxygen is stored in the muscles. Diving mammals typically have high levels of myoglobin, we typically don't.

Jaab Verbaas did an interesting test using a MOXY (a device that measures muscle oxygenation), his theory is that to create myoglobin increase within the muscle, SMO2 (muscle oxygenation) must drop to around 10% while SAO2 (arterial oxygenation) remains high.

He did a variety of exercises on full and empty lung breath holds, but he found it very difficult to create this state. In the end he found that performing a RV static followed by squats was getting his desired results.

But it was very tricky as peripheral vasoconstriction was hard to maintain while dry, the body would simply send blood to the muscles if the work rate was hard enough.

He was able to fine tune his training because he had access to the MOXY and could see what was happening to his SMO2 real time. He also described the feeling after the training as having his legs "wrung out by king Kong after a iron man race".

In essence the tough breath holds and damage to the muscles make this type of training unsustainable and thus myoglobin levels will not be affected.

KAATSU has been seen to drop SMO2 blow 10% without the need to breath hold or damage to the muscles. It is sustainable and safe to do regularly enough to hopefully cause adaptations of the myoglobin.

Disclaimer - our ability to increase myoglobin is not yet proven, nor is the level of benefit it will give to maximum performance in freediving.


The light loads, and other beneficial effects of KAATSU, means that we can train strength and build muscles even with an existing injury. KAATSU was originally developed to aid in rehabilitation and only later to develop sporting performance.


How do you do this training?

Blood flow restriction

It is important that the restriction is only on the venous blood leaving the limb, not the arterial blood entering the limb (eventually arterial blood will be restricted due to the "backup" of blood from the veins). This is done by regulating the pressure of the band creating the restriction. Venus flow is closer to the skin and requires less pressure to be restricted than Arterial flow.


Most studies have been done using bands that can be adjusted to a specific pressure (kind of like a small blood pressure band). This is ideal of course, but there is a catch - it will cost upwards of $2000 to get a basic set-up.

Fortunately there have been scientific and empirical results seen from far less expensive methods.

Blood flow restriction can be created by using weight lifting sleeves or wraps, I have been using bicycle inner tubes as they can be used in and out of the water. To get the right tightness, imagine a scale of 1-10, 10 being as tight as possible. You should wrap your limbs at 7 out of 10 on that scale.

Finding what is your "7" may take some fine tuning, if you aren't feeling enough lactate build up, it needs to be tighter, if you cannot finish the routine or you are loosing colour, you need to loosen up the straps.

The wraps sould be about 5cm wide and at the upper most of the limb (arms or legs).

How long?

The bands should not be on for more than 15 minutes, fortunately all we need is 7-10 minutes to get the desired results.

How to train?

Dry - Gym training should be done at 20% of your 1RM, 4 sets of the desired exercise will be done. I recommend back squats, front squats or leg extensions for the lower body and tricep pull downs or biceps curl for the upper body.

Set 1 - 30 repetitions - This depletes the slow twitch muscle and activates the anaerobic energy system and fast twitch muscle.

30 second rest

Set 2 - 15 repetitions - Now you will start to feel the burn.

30 second rest - The lactate will not leave the muscles so the burn will remain

set 3 - 15 repetitions - You may cry.

30 second rest - It won't feel like rest, just standing will be hard

set 4 - 15 repetitions - Good luck!

Take off the bands/wraps

Pool/Dynamic Training - The training can be done with surface swimming or on breath hold. I choose to do it on breath hold as it is more specific and the hold times are not challenging.

I recommend performing a 50m dynamic followed by 25m sprints. Keep track of the time so that the total protocol lasts no more than 10 minutes. The rest time between each sprint can be tailored to the individual, but I find 30 seconds to be sustainable.

Be careful to maintain proper technique, as the acidity of the muscles builds, your sprint will no longer seem much like a sprint, it will be hard to just keep moving, but be sure to keep moving with good form.

Continue performing the sprints until muscle failure or the 10 minutes is up.

How often can I do this training?

3 x per week has been seen to cause increases in size and strength, but it is safe to use this training daily or even multiple times per day. I would recommend building up slowly. Currently I will use BFR during each gym and pool session that I do, so about 5 x per week.



If you have any health issues or concerns it would be wise to see a doctor and seek advice before undergoing any BFR.

It would be very dangerous to perform these exercises at depth, restricting the blood flow will also restrict the bloods ability to absorb nitrogen from the tissues and could lead to DCS (decompression sickness).

KAATSU increases vascularity in the same way steady state cardio does. This may not be ideal for the dynamic disciplines. It is my belief that the benefits outweigh this one issue though. In the depth disciplines the stronger and faster peripheral vasoconstriction will Annul the issue of greater vascularisation.



KAATSU has been proven to increase performance within a variety of sports. But the potential benefits to freediving specifically are huge, I would say that freediving is the one sport that could gain the most from this type of training in fact.

The ease at which we can de-oxygenate the muscles, train lactate tolerance, and build strength leaves us with extra time and energy to train other things, which is hugely beneficial in a sport as multifaceted as ours.


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