Is the O2Trainer the Secret to Unlocking Your Lungs?
Author Byline: By David Miller / Last updated on August 21, 2025
Introduction
There's a specific hill on my favorite running trail. It’s not the longest, and it’s certainly not the steepest, but for the last six months, it's been my personal Everest. My legs always feel fine, ready to push harder, but about halfway up, my lungs betray me. It’s that familiar, frustrating burn—the feeling that you have more in the tank, but you just can't get enough air to use it. It’s the invisible wall of cardio. I’d tried everything: pacing strategies, different breathing techniques, you name it. Nothing worked. So, when I kept hearing whispers in fitness circles about the Bas Rutten O2Trainer, a strange-looking device that promises to train your most neglected muscle—your diaphragm—my skepticism was matched only by my desperation. I had to know if this was a legitimate training tool or just another gimmick sold by a famous fighter.
Is the O2Trainer the Secret to Unlocking Your Lungs?
Feeling stuck at a cardio plateau? My in-depth Bas Rutten O2Trainer review tests if this breathing device actually boosts endurance. Real results inside.
The Bottom Line Up Front (BLUF)
It’s not a gimmick. For anyone serious about improving their respiratory endurance and breaking through a cardio plateau, the O2Trainer is a highly effective, if slightly awkward, training tool that delivers measurable results.
Our Rating Breakdown
- Effectiveness: 9.0/10 (It genuinely works if you're consistent, leading to noticeable gains in lung capacity and stamina.)
- Ease of Use: 7.5/10 (The concept is simple, but it requires discipline and feels a bit strange to use initially.)
- Build Quality: 9.5/10 (Deceptively simple and bomb-proof. There are no electronics or moving parts to fail.)
- Value for Money: 8.5/10 (A one-time purchase for a lifetime of use makes it a solid investment compared to ongoing supplements or subscriptions.)
Overall Score: 8.6/10✨✨✨✨✨✨
Key Specifications at a Glance
- Training Type: Restrictive/Inspiratory Muscle Training (IMT)
- Material: Medical-Grade Silicone Mouthpiece
- Resistance Levels: 16 (via included, numbered caps)
- Included in Box: O2Trainer device, 16 resistance caps, carrying case, instruction manual.
- Primary Focus: Training diaphragmatic (belly) breathing and strengthening respiratory muscles.
Unboxing and First Impressions
The O2Trainer arrives in a no-frills package, which I appreciate. Inside, you find the main green unit, a small case with a dizzying number of tiny, numbered caps, and a simple instruction booklet. My first thought holding it was, "That's it?" It feels incredibly simple—a sturdy silicone mouthpiece attached to a small plastic chamber. There are no batteries, no apps, no charging cables.
The magic is in those little caps. They range from a wide-open hole to one that's barely a pinprick. The idea is to restrict airflow, forcing your lungs and diaphragm to work harder to pull in the same amount of air. It felt solid, well-made, and a bit like something you’t find in a medical setting, which, in this case, is reassuring. Assembly is intuitive: you just pop a cap on the end. I started with #13, as recommended for active individuals, and immediately understood the concept.
Putting It to the Test: Real-World Performance
You don't use the O2Trainer during your workout. You use it as a separate training session. Following Bas Rutten's own instructions, I committed to a simple routine: 30 reps, twice a day. I did my sessions in the morning while making coffee and in the evening while winding down.
The first few days were… weird. You place it in your mouth, forming a tight seal with your lips, and focus on pulling air deep into your belly. The restricted airflow is immediately noticeable. You can feel your diaphragm contracting. It’s not just breathing; it’s a conscious, physical effort. After a 30-rep set, my lungs felt like I'd just done a set of intense ab crunches.
The real test, of course, was that hill. For the first two weeks, I didn't notice a dramatic difference on my runs. But I stuck with the O2Trainer routine, gradually moving to a more restrictive cap (#10). Then, in the middle of week three, it happened. I was halfway up the hill, bracing for that familiar lung-burn, and… it never came. My breathing was deep, controlled, and efficient. My legs were burning, as they should have been, but for the first time, my lungs weren't the weak link holding them back. I pushed past my old stopping point and crested the hill with a feeling of pure exhilaration. That was the moment I was sold.
What Real Users Love (The Pros)
- Tangible Endurance Gains: This is the #1 reason to buy it. With consistent use, you will feel a real difference in your ability to perform during intense cardio activities.
- 'Why this matters to you:' It means running that extra mile, holding that note longer, or not being the one gasping for air on a group hike.
- Highly Adjustable Resistance: The 16 included caps offer a massive range of difficulty, making it suitable for everyone from beginners to elite athletes.
- 'Why this matters to you:' The device grows with you. You won’t outgrow its usefulness, ensuring long-term value from your investment.
- Simple, No-Electronics Design: There's nothing to charge, sync, or break. It's a purely mechanical tool that does one thing and does it well.
- 'Why this matters to you:' It's reliable and durable. You can throw it in a gym bag or suitcase without worrying about it. I’ve dropped mine plenty of times with no issue.
Common Complaints & Potential Deal-Breakers (The Cons)
- Looks and Feels Awkward: Let's be honest, you look a bit like a sci-fi movie character using it. It's definitely an "at-home" device.
- 'Why this matters to you:' If you're self-conscious, you'll need to find a private space to do your reps. It's not something you'd use at the office.
- Requires Consistent Discipline: This is not a passive device or a magic pill. You get out what you put in.
- 'Why this matters to you:' If you're not willing to commit to a few minutes of training almost every day, you will not see results and will have wasted your money.
- Cleaning Can Be Tedious: You have to disassemble it and wash it with soap and water regularly. It's not difficult, but it's another small task to add to your day.
- 'Why this matters to you:' For a device you put in your mouth daily, hygiene is non-negotiable. If you hate cleaning things, this might be an issue.
Is It Built to Last? Durability and Long-Term Value
Absolutely. This is where the O2Trainer shines. In an age of smart devices with planned obsolescence, this is refreshingly old-school. It's made of tough silicone and plastic. There are no batteries to degrade, no screens to crack, and no software to become outdated. Barring losing the tiny resistance caps (keep them in their case!), this device could very well last you a lifetime. This one-time purchase provides a training benefit that you can use for years, if not decades. That's incredible long-term value.
Best Alternatives (The Competition)
The main competitor in this space is PowerBreathe. While both aim to strengthen your lungs, they work slightly differently.
- Bas Rutten O2Trainer: Focuses on restricting airflow, making it harder to inhale and forcing you to use your diaphragm correctly. It’s about technique and muscle engagement.
- PowerBreathe Classic: Uses a calibrated, spring-loaded valve to provide resistance against inhalation (Inspiratory Muscle Training or IMT). It’s more like lifting weights with your lungs.
| Feature | Bas Rutten O2Trainer | PowerBreathe Classic |
|---|---|---|
| Mechanism | Airflow Restriction | Calibrated Valve Resistance (IMT) |
| Resistance | 16 Fixed Cap Levels | Manually Adjustable Dial |
| Feel | Simulates high-altitude breathing | Feels like breathing through a thick straw |
| Best For | Improving breathing technique, diaphragm control | Pure inspiratory muscle strength |
| Price | ~ $50 | ~ $55 |
For most people, the O2Trainer’s focus on proper diaphragmatic form is more beneficial for overall endurance, while PowerBreathe is excellent for pure strength building.
Frequently Asked Questions (FAQ)
- How long until I see results with the O2Trainer?
Based on my experience and other user reports, most people feel a noticeable difference in their cardio and breathing control within 2-4 weeks of consistent, daily use. - Can the O2Trainer help with asthma or snoring?
While it's marketed for athletic performance, many users report that strengthening their diaphragm and respiratory muscles has helped reduce snoring and provided better breathing control during asthma flare-ups. However, you should absolutely consult your doctor before using it for any medical condition. - Is the O2Trainer difficult to clean?
It's not difficult, just necessary. You simply take it apart, wash the components with warm, soapy water, rinse thoroughly, and let it air dry. It takes about two minutes. - What resistance level should I start with?
The guide is helpful. It generally recommends starting around cap #14 for inactive individuals and #13 for those who are regularly active. The key is to choose a level that is challenging but allows you to complete 30 reps with good form. - Does it really teach you "belly breathing"?
Yes. Because the airflow is restricted, you are physically unable to take shallow, chest-based breaths. It forces your body to engage the diaphragm to pull air deep into the lungs, which is the entire point.
Final Thoughts & Recommendation
That stupid hill on my running trail isn't my Everest anymore. It's just a hill. The O2Trainer didn't make my legs stronger, but it unlocked the engine that powers them. By forcing me to train the most fundamental part of my endurance—my breathing—it removed the bottleneck that was holding my performance back.
This isn't a device for the casual gym-goer or someone looking for a shortcut. It's a specialized tool for people who are serious about their performance and are willing to put in the work. If you're a runner, cyclist, swimmer, martial artist, or even a singer who feels like you've hit a respiratory wall, the Bas Rutten O2Trainer is a legitimate, high-value, and incredibly effective tool to help you smash right through it. It was worth every penny for me.
Call to Action
If you've hit a wall in your training, this might just be the tool you need to break it down.
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