CO2 Tables: A Guide to Improving Breath-Holding Performance

CO2 and O2 tables might sound like something out of a chemistry class, but they’re actually super handy training tools for freedivers—and anyone looking to improve their breath hold. If you’re wondering what they are, don’t worry—I’ll explain it all in this article, including how and why freedivers use them to safely practice breath holds.

These tables aren’t just for freedivers; swimmers and breathwork practitioners also use them, and you don’t have to be an athlete to benefit. They can help with mental focus, resilience, and even improving your mood.

I first came across CO2 tables while training to become a freediving instructor. Since then, they’ve been part of my freedive training and a standalone breathwork practice I enjoy alongside meditation. For me, they’re a deep form of meditation, helping my mind slow down and focus.

There are also physical health benefits to breath-hold training. These include increased lung capacity, better oxygen efficiency, more red blood cells, and improved blood circulation. These changes lead to faster recovery, better sleep, enhanced cognitive ability, and a stronger immune system.

Even if extending your breath hold isn’t your goal, CO2 and O2 tables can still have a profound impact on your mental and physical well-being.

In this article, I’ll focus on what CO2 tables are, explain how they work, and provide a beginner-friendly example. If you’re interested in O2 tables, keep an eye out for my separate article on that.

Let’s dive in.

What Are CO2 Tables?

CO2 tables get talked about more often than O2 tables, and for a good reason. They’re a technique designed to help you build tolerance to the buildup of carbon dioxide in your body during breath holds.

That uncomfortable urge to breathe, the tightness in your chest or the stiffness in your stomach, is your body’s response to rising CO2 levels.

For beginners this is often more important to train than o2 tables, where the focus is on your tolerance to low oxygen. That isn’t normally what stops beginners from progressing, it is the physical and mental feeling of the urge to breath otherwise known as carbon dioxide buildup.

Here’s how it works: when you hold your breath, oxygen gets used up and CO2 builds up in your body. This buildup triggers your brain to send signals like, “Hey, it’s time to breathe!” You’ll start feeling physical sensations like chest tightness or diaphragm contractions.

Contractions, by the way, are your diaphragm moving up and down, trying to force you to breathe. They’re uncomfortable, yes, but they’re also helpful. They serve as your body’s warning system, letting you know you’re about halfway through your oxygen reserves.

If you experience contractions at 1 minute, you might still have enough oxygen to hold for another minute—if you can handle the discomfort.

CO2 tables are designed to train you to cope with these sensations. They involve breath holds of the same duration but with shorter and shorter rest intervals between holds. The goal isn’t to push your limits but to build comfort and endurance gradually.

By training with CO2 tables, you develop mental resilience and physical tolerance to that urgent need to breathe. This is a critical skill in freediving, where mental control often limits your progress more than physical capability.

So, embrace those contractions—they’re your friends!

When to Train CO2 Tables and How Long

CO2 tables are done dry (on land), so you can practice at home whenever it’s convenient. As a beginner, training 2-3 times a week is a good starting point. You’ll likely notice improvements in both your breath hold and comfort level pretty quickly.

Each session lasts about 10-15 minutes and typically includes up to 8 intervals. For best results, try doing them first thing in the morning before eating—while you’re still relaxed and maybe even half-asleep. This helps your body store oxygen more effectively.

But remember: listen to your body. If you’re not feeling well or aren’t in the right mindset, skip the session. Overtraining or stressing about it defeats the purpose.

Example of a Beginner CO2 Table

Here’s a beginner-friendly CO2 table:

Interval	Breath Hold Duration	Rest Interval Duration
1	0:30	1:30
2	0:30	1:15
3	0:30	1:00
4	0:30	0:45
5	0:30	0:30
6	0:30	0:30

As you gain confidence, you can increase the breath-hold duration or shorten the rest intervals.

Tips for Beginners

1. Start Slow: Begin with a few minutes of relaxed breathing to lower your heart rate.
2. Focus on Comfort: Adjust breath holds or rest intervals as needed to keep the practice manageable.
3. Stay Consistent: Regular practice (without overdoing it) leads to steady progress.

Tips for Training CO2 Tables

• Set realistic goals to avoid burnout.
• Practice dry tables lying down in a quiet, comfortable space. Don’t train in the water unless you have a buddy with you.
• During rest intervals, focus on slow, deep breathing to lower your heart rate. The slower your heart rate is the longer you can hold your breath as you’re not burning as much oxygen.
• Consider combining tables with diaphragmatic breathing or meditation for deeper relaxation.

Conclusion

With a few weeks of practice, you’ll likely notice an improvement in your CO2 tolerance and overall breath-hold comfort. Progression feels rewarding, but don’t get ahead of yourself. Hypoxia is your next obstacle, which is where 02 tables come in! Progression should be slow and steady.

Breathwork is a deeply grounding practice for me, connecting my mind and body. I hope you’ll feel the same after a few rounds of these tables.

You might also notice better sleep, a calmer mind, and more energy throughout the day. This training builds mental and physical endurance, and the benefits can spill into all aspects of your life.

If you’re an athlete, give CO2 tables a try for a month and see how they enhance your performance. I’d love to hear your experiences—drop a comment if you have any thoughts or questions.

Enjoy the practice and the amazing things your body can do!