Oh, carbon dioxide. Such an important gas for freedivers, yet so uncomfortable and annoying…for most of us at least. But as annoying as CO2 is, it is really useful to get used to that unpleasant feeling, embrace it even, and build up a tolerance to it. For beginners especially, static CO2 training can greatly improve breath-hold time in a fairly short timespan. Beginners that are training dynamic CO2 tables should take it a bit easy and stay focused on proper technique until it is deeply ingrained since being stressed underwater can lead you to become sloppy and possibly create bad habits.

So what should you keep in mind before starting any of these tables? First of all, when training, always have a trained buddy, and no…your local pool’s lifeguard does not count. These tables can be adjusted to your abilities, so if a table seems too easy or too hard, make it a longer or shorter distance or breath-hold time. Make sure not to over-train; freediving should still be fun, so it is better to begin slowly and increase over time. In the beginning, training CO2 tables three times a week with a rest day in-between is advised.

NOTE: all of these tables should be performed with a trained freediving buddy

Static

The classic static CO2 table can take a lot of time, often over 20 minutes for most people, and while it is a helpful table, not everyone wants to wake up extra early before work to complete this table on an empty stomach.

One-breath table

An alternative is the “one-breath” table, where you hold your breath for 1:00. At the end of the breath hold, you take one full exhale, and one full inhale and hold again for 1:00. Repeat 8 to 10 times, or until it becomes too difficult. This table takes much less time than the classic CO2 table, as contractions kick in earlier and breathe-up time is minimized.

Dynamic

Training dynamic CO2 tables are extremely useful, not just for CO2 tolerance, but for lactic acid tolerance as well. If you are performing a CO2 table, only do one per training day, whereas the other exercises can be performed multiple times, but should be stopped if you feel a headache from the CO2 or too much lactic acid buildup.

16x25m (82ft) table

Begin in a pool, completely relaxed, with your normal breathe-up. The objective is to dive 25m in one breath, surface at the edge of the pool, and recover. You choose the amount of time you have to recover and breathe-up, but as you repeat this 15 more times, try to keep the total time for the table as short as possible. An advantage of this table is that it is up to you how challenging it is, whether you take a longer or shorter recovery time. After a few practices, you can set new time limits for yourself to train against.

25m (82ft) fast, 25m slow

On a single breath, fin the first 25m as fast as you can, and upon turning, without surfacing, continue another 25m as slow as possible. Contractions will be strong, but the objective is to challenge yourself by swimming as slow and as steady as you can.

25m (82ft) dynamic, float up static

Begin with 25m of dynamic on a single breath, but at the end, instead of surfacing, make the turn and stay underwater. Stop moving, relax your body, and begin static, letting your body float to the surface and making sure your buddy is keeping you in place. Go for 1:30, more or less, depending on your personal ability.

50m (164ft) dynamic with decreasing total timetable

Begin by selecting a total time, which is the time it takes between the beginning of one dive to the start of the next, for example: 2 minutes. Swim 50m on a single breath, surface, and recover. If it takes you 1:30 to do the full 50m, then you have 30 seconds of recovery time before your next 50m. Reduce the total time every few laps. This table helps you discover which is better: swimming faster with stronger contractions and more recovery time, or swimming slower, with more controlled contractions, and less recovery time.

Static + dynamic

As simple as it sounds: begin with static, and as soon as you feel your first contraction, duck dive and go straight for 25m (82ft) dynamic. If 25m becomes too easy, adjust the distance to make it challenging.