Safety First

Hyperventilating before a dive - taking many fast, deep breaths - reduces your urge to breathe without increasing oxygen. It dramatically increases the risk of loss of consciousness underwater. Never do it. The techniques described here do not involve hyperventilation.

— Chapter 01

The Foundation: Diaphragmatic Breathing

Breathing before a dive is not about getting more air into your lungs. It's about preparing your nervous system to be calm underwater, and your physiology to use the oxygen you already have as efficiently as possible.

Most people breathe with their chest — the ribcage expands, the diaphragm barely moves. This is adequate for daily life but inefficient for freediving preparation. Diaphragmatic breathing involves the belly expanding on each inhale as the diaphragm pulls downward, drawing air to the bottom of the lungs.

How to practice it

  1. 01 —Lie down flat
  2. 02 —Place one hand on your chest, one on your belly
  3. 03 —Inhale slowly — your belly hand should rise first
  4. 04 —Your chest hand should rise after, and less dramatically
  5. 05 —If only your chest moves: you're chest-breathing

Why it matters

Engages lower lung lobes
where blood flow is highest — more oxygen per breath
Activates parasympathetic nervous system
slowing heart rate and promoting relaxation
Greater air volume
a full diaphragmatic breath holds more air than a shallow chest breath
— Chapter 02

The Pre-Dive Breath-Up

The breath-up is the 2–3 minutes of breathing before each dive. The goal is not to ventilate maximally — it's to arrive relaxed, with a normal CO2 level and a heart rate below resting.

The correct sequence

  • Breathe slowly and calmly for 2–3 minutes
  • Target 6–8 breaths per minute — significantly slower than normal
  • Exhale fully on each breath — leave no residual air in the lungs
  • Your last breath before the dive is a smooth, full inhale — not a sharp gasp

The dive starts from this full inhale. You do not take multiple sharp deep breaths to 'load up.'

— Chapter 03

Recovery Breathing After the Dive

What you do immediately after surfacing is as important as the breath-up.

The recovery protocol — mandatory every dive

  1. 01 —Exhale first on surfacing — not inhale
  2. 02 —Take one full recovery breath
  3. 03 —Repeat for 3 full breaths total
  4. 04 —Give your buddy the OK signal
  5. 05 —Rest at least twice the dive time before the next dive

Loss of motor control (LMC) and blackout can occur at or near the surface, even after a successful ascent — oxygen continues to drop during the final meters as pressure falls. Your buddy must watch you through the completion of recovery breathing, not just until you surface.

— Chapter 04

Breath Control During the Dive

Once underwater, preparation is done. Focus on reducing oxygen consumption:

  • Minimize movement — every twitch costs oxygen
  • Relax your face — facial tension elevates heart rate measurably
  • Slow kick cadence — not fast, not aggressive
  • Go passive in free fall — below neutral buoyancy, stop finning entirely

The diaphragm contractions you feel are CO2-driven — not a sign you're running out of oxygen. They're uncomfortable but safe. Training builds tolerance to them.

— Chapter 05

The Five Rules

  1. 01 —Breathe diaphragmatically — belly first, not chest
  2. 02 —Slow your breath rate before a dive — 6–8 breaths per minute
  3. 03 —Never hyperventilate — it removes safety margins without adding oxygen
  4. 04 —Exhale first on surfacing, then three full recovery breaths
  5. 05 —In the water: relax, slow down, let the dive come to you