Breath Hold Timer

How to do a max breath-hold test

The point is a repeatable number, not the largest one you can survive. CO2 and O2 tables are scaled from it, so a rushed test produces a session at the wrong intensity.

1. Stay on dry land. Sit or lie down somewhere stable, away from water. Never test a maximum hold in a pool, bath, or open water. This timer is for dry-land use; using it in water risks shallow water blackout.
2. Settle your breathing for about two minutes. Calm and normal. Do not hyperventilate: rapid or repeated deep breaths lower carbon dioxide and blunt the warning while oxygen keeps falling, which is the mechanism behind hypoxic blackout.
3. Take one comfortable full breath. Fill low to high in one smooth inhale. Full, not strained.
4. Hold and stay still. Keep the jaw, shoulders, and hands loose. Involuntary breathing movements may appear; their timing varies between people and attempts and tells you nothing about how much oxygen is left.
5. Stop early rather than late. End the hold at your limit and take calm recovery breaths. Stop for the day at any dizziness, confusion, or visual disturbance.
6. Record one attempt per session. Repeat attempts drift, and note the conditions so the next number is comparable.

There is no meaningful published norm for untrained adults, so compare the reading with your own earlier attempts rather than with anyone else. Retest every few weeks. If you want the gentler measurement that stops at the first urge to breathe, use the CO2 baseline test instead, and read the safety guide before your first table.

Tips for a Better Breath Hold