How to Make an O2 Table for Static Apnea

Once you've spent several weeks building CO2 tolerance and your urge-to-breathe response no longer derails your sessions, you hit a new ceiling: your actual oxygen limit. This is where the O2 table enters the picture. Unlike the CO2 table — which keeps holds fixed and shrinks rest periods — the O2 table does the opposite: it keeps rest fixed and progressively increases hold times until you're approaching your real physiological maximum. It's a more demanding protocol, and it needs to be approached with discipline and the right preparation.

This guide explains exactly how to build an O2 table for static apnea, gives you two worked examples (beginner and intermediate), and outlines the safety principles you must follow before adding this tool to your training.

What Is an O2 Table?

An O2 table is a structured breath-hold training protocol in which the rest time between apneas stays constant, while the duration of each hold increases progressively across rounds. The goal is to train your body to use oxygen more efficiently and to extend your actual breath-hold ceiling — not just your tolerance to the discomfort of CO2 buildup.

Here's why this matters: CO2 tables make you comfortable with the urge to breathe, but they don't necessarily push your oxygen use to the limit. O2 tables do exactly that. By the final rounds of a well-designed O2 table, you should be reaching 80–90% of your maximum personal record. This trains oxygen efficiency, improves your ability to suppress the dive reflex trigger point, and genuinely extends the ceiling of what you can achieve.

The key parameter is the rest period. It's set long enough to allow meaningful recovery — typically around twice your maximum hold time — but it doesn't get shorter as the session progresses. The difficulty comes entirely from the increasing breath-hold targets.

O2 Table vs CO2 Table — Quick Reminder

If you're still early in your training, you'll want to read our full CO2 table guide first. In short: CO2 tables shrink rest periods to force your body to deal with elevated carbon dioxide — this reduces the urgency of the diaphragm contractions and builds mental resilience. O2 tables, on the other hand, progressively increase hold duration while rest stays constant — this trains the body to extract oxygen more efficiently and extends the raw time ceiling.

For a side-by-side breakdown of both protocols, see the CO2 vs O2 table comparison.

The practical takeaway: start with CO2 tables for the first 4–6 weeks of training. Add O2 tables once you have a stable personal record and can complete CO2 sessions without feeling overwhelmed.

How to Build an O2 Table

The Basic Formula

Building an O2 table from scratch requires just three pieces of information: your current personal record (PR), the number of rounds you want to complete, and the increment size between holds.

• Rest period: Fixed throughout the session. Set it at approximately twice your maximum hold time. If your PR is 2 minutes, rest for 2 minutes between rounds. This is non-negotiable — reducing it turns the session into something between a CO2 and O2 table and defeats the purpose of the protocol.
• Starting hold: Begin at roughly 50% of your personal record. This gives you a gradual warm-up and prevents you from exhausting your oxygen reserves too early in the session.
• Increment size: Increase each hold by 15–30 seconds per round. Smaller increments (15s) make for a smoother, longer session. Larger increments (30s) are appropriate when you have fewer rounds to complete.
• Number of rounds: Aim for 6–8 rounds. Eight rounds with 15-second increments gives you a 1:45 progression window from start to finish.

The final hold of your table should be at or slightly above your personal record. Hitting it successfully means your training is working. If you can't complete the last round, reduce the increment for next session rather than cutting the rest period short.

Example — Beginner O2 Table (2-min max)

In this table, rest is fixed at 2:00, the starting hold is 1:00 (50% of the 2-minute PR), and increments alternate between 15 and 10 seconds for a natural progression. The final hold of 2:30 is 125% of the PR — achievable with progressive training.

Example — Intermediate O2 Table (3-min max)

Here the rest is fixed at 3:00, starting hold at 1:30, with 15-second increments throughout. The final hold of 3:30 represents 117% of the PR. At this level, the later rounds are genuinely demanding and require full mental focus.

When to Add O2 Tables to Your Training

O2 tables are not for beginners. If you've never done structured breath-hold training before, start with CO2 tables and build a foundation over 4–6 weeks. You should be comfortable completing a full CO2 session, have a stable and repeatable personal record, and understand your body's specific response to hypoxia before introducing O2 tables.

Signs you're ready to add O2 tables:

• Your personal record has been stable for at least 2–3 weeks
• You can complete CO2 table sessions without aborting rounds early
• You understand the difference between CO2 discomfort and genuine oxygen depletion
• You have a training partner or are doing dry training under safe conditions

Safety Rules

O2 tables are fundamentally different from CO2 tables in terms of risk. Because you are approaching your actual oxygen limit, the risk of hypoxic blackout is real — especially in the final rounds. Every safety rule is mandatory, not optional.

• Never train alone in water. O2 tables should only be done in-water with a trained safety buddy present and watching. Dry training (on a couch or yoga mat) is safer but should still ideally have someone nearby for the final rounds.
• Never hyperventilate before holds. Hyperventilation lowers CO2 without raising O2, which eliminates the urge-to-breathe warning signal and increases blackout risk dramatically. Take one or two slow, full breaths and hold from normal ventilation.
• Stop immediately if you feel lightheaded, dizzy, or experience visual disturbances. These are pre-hypoxic signals. End the session and do not attempt the next round.
• Do not skip rest periods. The fixed rest is the safety mechanism of the O2 table. Cutting it short puts you into the next hold with insufficient oxygen recovery.
• Know the difference between discomfort and danger. CO2 contractions are uncomfortable but safe to push through. Oxygen depletion warning signs — tingling in extremities, tunnel vision, sudden calm — are physiological alarms that must not be ignored.

Combining CO2 and O2 Tables

Once you're training with both table types, session scheduling becomes important. Both protocols are physiologically demanding and require adequate recovery between sessions. A practical weekly structure for intermediate freedivers:

• Monday: CO2 table session
• Wednesday: O2 table session
• Thursday: CO2 table session (lighter variation)
• Friday/Saturday/Sunday: Rest or easy pool work

The key rule: allow at least 48 hours between O2 table sessions. These sessions place a significant adaptive demand on your oxygen metabolism and your central nervous system. Training O2 tables on back-to-back days degrades performance and increases blackout risk.

CO2 sessions can be done more frequently because the stress is primarily respiratory-tolerance based rather than hypoxic. Still, even CO2 sessions benefit from a rest day between them.

Track Your O2 Tables With Anima Apnea

Building and tracking O2 tables manually — calculating rest periods, incrementing hold times, timing each round with a stopwatch — is manageable but tedious, and it takes mental bandwidth away from the session itself. Anima Apnea automates the entire process.

The app reads your personal record, generates an O2 table with the correct rest period and progression, and guides you through each round with audio cues. After the session, every hold time, recovery quality indicator, and performance trend is saved automatically. Over weeks of training, you can see exactly how your oxygen ceiling is moving and adjust your tables accordingly.

The structured logging also helps you identify when you're ready to move your PR target — because progress in freediving isn't always obvious in real time, but it becomes very clear when you look at six weeks of session data side by side.