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“Any professional athlete knows, that having stamina is THE most important thing there is in competition. Throughout my entire Mixed Martial Arts career, I have never ran out of gas. Like they say, you can have a Ferrari, but when you don’t fill it with gas, it won’t drive. The O2 Trainer will give you stamina like you have NEVER had before”.

Bas Rutten
– Three Time King of Pancrase World Champion
– UFC Heavyweight Champion of the World

View the Breathing Technique Video in the left column. It’s a good idea to train with no cap for the first 5 minutes of your workout, or during your warm up routine; warming up your lungs is as important as warming up any other muscle.

The flap has two little holes in them that align with the holes inside the cap, please click here to watch the Re-Attach Flap Video for more detailed instructions.
We recommend warming up with no cap at all for 5 minutes to get the lungs warmed up. After that you will be ready to use the caps and do a full workout.
This is a good sign and totally normal especially in the first 15 minutes. What you are feeling is the lung muscles being put to work and being filled with lactic acid. This should subside after 15 minutes and if you are still feeling it, you are probably working your lungs too hard. Give your O2 Trainer exercising a break for the day and try again with your next workout or the following day!
This is a very good indication that you are using the O2 Trainer properly, and that you are breathing through your diaphragm, with proper form!
Using the unit O2 Trainer 4 times a week, during intense conditioning workouts should be enough. You are training your lung and diaphragm muscles and they will be getting a powerful workout; to maximize their strength they do need a chance to rest! To get the most out of any workout routine, you need to take breaks and alternate your areas of focus and let your muscles take a break!
Yes you can, since they are much shorter then your normal workouts. Make sure you exhale all the way, and then inhale while using your diaphragm and keep your shoulders relaxed. Focus on your core to “pull” the air in. Four sets of 12 each, with one minute rest in between, will be perfect. Just take the screen that you feel the most comfortable with and train your lungs anywhere you want.
It’s simple – when you can do your workout without “cheating” (getting extra air by opening your mouth around the mouthpiece) and it becomes relatively easy, that is when you are ready to make the switch to the next screen. If you are struggling to get through the workout, you are NOT ready to change screens. Easy does it, take your time and work towards your goal!
Common now, OF COURSE you do! Feeling dizzy is not a normal effect, and is a good indicator that you need to use a lower numbered screen. Don’t push yourself too hard, all of the screens will train your lungs – proper form yields the best results!
With the old model (the square looking one) the "jumping splits logo" should be on top and the exhale cap (cap with the flap) should be on the LEFT.
With the new (rounded) model named: "O2Trainer 2.0", it doesn't matter where you have the caps
Gently clean the O2 Trainer with soap and warm water. You should always cleanse the unit before storing to keep it fresh and sanitary!
Yes, you are rebreathing a little bit your own breath, but I made it on purpose this small so it’s almost nothing.

STILL, there are studies done right now that might show a “spark in red blood cell count” when “rebreathing” your own breath.

Many swimmers use their snorkels outside the pool for this, to tell you the truth I had this idea for the o2trainer since I was 14. I told all my friends about it. About 5 years ago Wanderlei Silva (An MMA fighter) was shown on TV training with a snorkel device while doing his “bag work”. I had 6 or 7 phone calls that night from all my friends who watched that show as well and said: “Bas, you have to start making the Ruttenizer (that was my original name, haha), because otherwise somebody else is going to come up with it”

And that’s where I started working on the patent.

I always thought that by using a snorkel device you rebreathe too much of your own breath and that’s why you see people passing out sometimes when doing this. I wanted to make this a safe product so I made it on purpose this small.

In other words, no need to worry, (I posted this on the website last week as well) just use it as directed and only when your workout becomes “easy” again, and only then, you switch to just 1 harder setting. Don’t skip a setting, just go 1mm smaller every time till you are used to it because that means your inspiratory system (core, diaphragm and lungs) is stronger now and pulls the same amount of air through the 1mm smaller hole as it did before with the bigger hole.

The o2trainer never claims that it’s the same as high altitude training. The reason is that if you use the o2trainer correctly, you will always have enough oxygen. At high altitude there is simply less oxygen in the air. Tthat means however deep, hard and fast you breathe, you won’t get your normal o2 intake.


It’s very hard to mimic this with a lung training device. I know some other people who sell those devices claim this, but they can’t since every person has a different inspiratory system, some are simply stronger then others.

However, we have had many messages from people who claimed the o2trainer DID help at high altitude. Michael Kuiper (MMA fighter) came from Holland 4 days before his UFC fight in Colorado, which is a mile-high as you know, and Holland is at sea level. He beat his opponent in a very hard “conditioning” bout while never training at high altitude

The correct way of using the o2trainer is to slowly but surely go down in size hole, ONLY when you feel that you get the same amount of air as you had before using the o2trainer, than you go a size smaller. Now you made your inspiratory system stronger because you taught it to pull in the same amount of air that you had before.

* Example: When I tell you “screen 4” is the same as 7000 ft (I am just making that up right now), then you might pull in enough air in the beginning of your workout but when you get tired, which will be fast because you push your inspiratory system hard, you simply can’t pull the same amount of air in, so then screen 4 feels like it’s becoming screen 6 or 7. (More about that at the end of this answer where you see *) And when your body doesn’t get enough air it will also work not as hard for you, your brain and muscles slow down. Imagine a surgeon giving a patient, who he is operating on, less oxygen, that would be bad. That’s why nowadays many Olympians train at sea level but eat, sleep and live in a high altitude home, this way their bodies perform 100% when training and they STILL increase red blood cells by living at “high altitude”

Conclusion, when you start training with the o2trainer three months before you have an event at high altitude and you use it as I directed above, your lungs WILL become stronger and more efficient which will help you at high altitude for sure. But although a Doctor saw a slight increase in red blood cells when using the o2trainer, its real job is making the lungs stronger and more efficient, so NOT increasing the red blood cell level. Or you have to use it like 6-8 hours a day keep it in even after training. Still then, if you decide to do that, start with a bigger size hole and work yourself gradually up to smaller size holes because you want to give your body it’s number ONE need, and that’s enough OXYGEN so it will perform at it’s best when working out

Big explanation, but an important one!

*Your breathing is done by your diaphragm,please view the video on the left titled How Breathing Works. When you breathe in your chest expands and will create a vacuum between the body and the lungs which will pull the lungs open, when exhaling your press your core together and the air out of your lungs. This means that your lungs do some work, but the real powerhouse in breathing is your diaphragm and intercostel muscles (muscles between the ribs). Since they are MUSCLES they get tired, same as when you train, for instance, your biceps, the second set (when you really pushed your first set) will have less repetitions. But the more you train them, the better they start working and the longer they can keep pulling in the same amount of air.

No, it is totally a personal preference if you decide to either train with the nose clip or won’t. Some people can’t control the air that goes in through their noses, they can’t separate it from “mouth breathing”, those should use the nose clip.

We hope to add smaller sizes available for the age 8 + in the near future.
The standard packaging is the biodegradable carton packaging , and the plastic case is a plastic case which can hold your o2trainer and screens when you would like to stay organized . The carton case has a mesh net with zipper which you can use to keep all together . This choice of packaging is only for the green O2Trainer.