CO2 Tolerance Table

A structured table with a fixed hold and progressively shorter rests, done on dry land. Raises tolerance to the discomfort of rising CO2. Never practised in or near water.

DIFFICULTY
Advanced
EQUIPMENT
Timer · Mat
PRIMARY MUSCLES
Diaphragm
ALSO WORKS
Transverse Abdominis · Neck
HOW TO DO IT
  1. 01Sit or lie down somewhere safe on dry land, never in, on or beside water, and never alone if you are new to breath holds.
  2. 02Find your comfortable hold time first: inhale normally, hold, and stop at the first strong urge to breathe — not at your maximum. Use half of that figure as your working hold.
  3. 03Round one: breathe normally for 90 seconds of rest, then perform your working hold.
  4. 04Reduce the rest by 15 seconds each round — 90, 75, 60, 45, 30 — while keeping the hold length identical every time.
  5. 05Complete 5 to 6 rounds total, then stop. Do this no more than 3 times a week.
  6. 06Finish with 2 minutes of quiet nasal breathing without any holds.
COACHING CUES
  1. 01The hold never changes. Only the rest shrinks.
  2. 02Breathe normally in the rests — no hyperventilating to buy an easier hold.
  3. 03Stop at the urge to breathe, not at the edge.
COMMON MISTAKES
  1. 01Performing any breath hold in or near water, which is how shallow water blackout happens and is the single most important rule here.
  2. 02Hyperventilating before a hold to extend it, which suppresses the urge to breathe without adding oxygen and removes your warning signal.
  3. 03Practising this during pregnancy, with uncontrolled hypertension, cardiovascular or respiratory conditions, epilepsy, or a history of fainting — deliberate retention work is not appropriate in those situations.

Note: Reference material, not a prescription. Load, volume and whether this movement suits you at all depends on your assessment — if something hurts, stop and get it looked at.

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