ApneaO2 Tables for Freediving: Train Your Body for Low Oxygen
An O2 table is the mirror image of a CO2 table: the rest periods stay fixed while each breath hold gets progressively longer, finishing near 80 percent of your maximum. Where CO2 tables teach you to tolerate the urge to breathe, O2 tables train your body to keep working as oxygen levels genuinely drop. Together they are the twin engines of freediving breath hold training.
CO2 tables vs O2 tables at a glance
| CO2 table | O2 table | |
|---|---|---|
| Hold length | Fixed (about 50% of max) | Increases every round |
| Rest length | Decreases every round | Fixed (about 2:00) |
| Trains | Tolerance to rising CO2 | Function at lower O2 |
| Feels like | Growing urge to breathe | Progressively longer, deeper holds |
| Best for | Beginners, spearfishing, surf fitness | Pushing your max, static apnea goals |
A worked example: O2 table for a 2:00 max
| Round | Breathe (rest) | Hold |
|---|---|---|
| 1 | 2:00 | 1:00 |
| 2 | 2:00 | 1:07 |
| 3 | 2:00 | 1:14 |
| 4 | 2:00 | 1:21 |
| 5 | 2:00 | 1:28 |
| 6 | 2:00 | 1:35 |
| 7 | 2:00 | 1:42 |
| 8 | 2:00 | 1:40 to 1:45 (about 85% of max) |
The early rounds should feel almost too easy; that is by design. The final two or three holds are where adaptation happens. You should finish the last hold challenged but in control, never straining to a near-blackout. Training to failure is counterproductive and unsafe.
When to use O2 tables
Start with two or three weeks of CO2 tables first: they deliver the fastest early gains and teach you what the urge to breathe actually feels like. Then add one O2 table per week, keeping at most one table of any kind per day. A classic week is two CO2 sessions plus one O2 session, then a max retest every one to two weeks. If your max moves, rebuild the table; an O2 table anchored to an old max stops stretching you.
In the Apnea app
Apnea generates both table types from a single number: your tested max. Every hold and rest is timed and announced with audio coaching you can customise or mute, sessions sync from Apple Watch, and the progress chart shows your max climbing as the tables scale with you. Advanced divers can also build fully custom tables.
Signs your O2 training is working
- The first urge to breathe arrives later into each hold.
- Contractions start later and feel less alarming.
- Your recovery breaths after a long hold feel calm instead of desperate.
- Your retested max creeps up without any heroic single attempt.
Safety first
Do all table training dry: sitting or lying down on land. Never practice breath holds in water without a trained buddy watching you, never hyperventilate before a hold, and never do breath holds while driving. If you have a heart or lung condition, or you are pregnant, talk to a doctor before training. Blackouts can happen without warning, even to experienced divers.
Your next personal best is a table away
Apnea builds O2 tables matched to your current max and guides every interval with audio, so each week ends a little closer to the hold you thought was impossible.
Free to download. 4.8 stars, 2,894 App Store ratings.