Carbon dioxide tables are a great way to train your mind and body to tolerate excess levels of carbon dioxide (CO2). The tables train you to deal with that burning feeling of needing to breathe. As you may know, carbon dioxide in our bloodstream is actually what signals our brain to urge us to breathe. Normally, our bodies remain balanced between metabolizing oxygen and producing CO2 as a waste product. If our body is consuming more oxygen, such as during an intense workout, it will consequently produce higher CO2 in our blood, which our brain interprets as the need to breathe harder or faster.
When holding your breath, you cannot relieve yourself of this CO2, so the effects will become more and more uncomfortable, eventually resulting in that burning sensation and diaphragm contractions. The burning doesn’t necessarily mean that you’re running low on oxygen and need to breathe, but your brain doesn’t know that.
A CO2 table is basically a series of breath holds which gives you less and less time to recover in between each breath hold. This causes the CO2 in your blood and tissues to slowly creep up throughout the exercise. The slow increase develops your tolerance to CO2. People who have a really strong, or early desire to breathe should concentrate on CO2 tables. They can be performed in water (stationary or dynamic) or on the surface.
A dynamic CO2 table is performed while swimming underwater, either with fins or without. In this video, I start by swimming a length of the pool (25 meters), then I breathe for 30 seconds. I then immediately swim another length, and breathe for 25 seconds, then another length, breathing for 20 seconds, and so forth. The last length is after 5 seconds of breathing. Sometimes I’ll do an extra 5 second length.
My CO2 table looks like this:
REST: 90 Seconds ; SWIM: 25 Seconds (25 Meters) – Breathe-up
REST: 30 Seconds ; SWIM: 25 Seconds (25 Meters)
REST: 25 Seconds ; SWIM: 25 Seconds (25 Meters)
REST: 20 Seconds ; SWIM: 25 Seconds (25 Meters)
REST: 15 Seconds ; SWIM: 25 Seconds (25 Meters)
REST: 10 Seconds ; SWIM: 25 Seconds (25 Meters)
REST: 05 Seconds ; SWIM: 25 Seconds (25 Meters)
REST: 05 Seconds ; SWIM: 25 Seconds (25 Meters) – optional
The great thing about dynamic CO2 tables versus stationary CO2 tables is you can work on your free-diving technique while experiencing the somewhat intense effects of CO2. This is a great time to focus on your finning technique, keeping your body streamlined and maintaining consistent speed. Note that the speed should remain consistent throughout the exercise. I usually try to keep my pace at 1 meter / second. Make sure not to speed up at the end as you could get a blackout very easily. Also, the breathing between each length should be regular, not large breaths. I usually just take one big breath five seconds before, but am working on eliminating that. The whole point of the exercise is to experience high levels of CO2, which you won’t feel if you’re oxygenating too much throughout the exercise.
Dynamic CO2 tables train you to be a more efficient free-diver, your breath hold and technique will improve and your body will become more accustomed to high levels of carbon dioxide as well as low levels of oxygen. Accustoming the body to these extreme conditions is a long process, noticeable results will not appear within days or even weeks – however persistence in static training will lead to a dramatic improvement in the long run.
*Safety Note: Do not practice apnea tables underwater without direct supervision. If you pass out, it doesn’t matter how deep the water is!