CO₂ might be more important than O₂

Most of us grew up learning one thing about breathing: oxygen good, carbon dioxide bad. Oxygen is life. CO₂ is waste. Breathe it out, get rid of it, repeat.

It’s one of the most widespread misconceptions in health. And it’s costing us.

The Bohr Effect

In 1904, Danish physiologist Christian Bohr discovered something that should have changed everything. He found that oxygen doesn’t simply travel from your lungs to your cells automatically. It needs a trigger to be released from your red blood cells.

That trigger is CO₂.

Without enough carbon dioxide in your blood, oxygen stays locked inside your red blood cells — unable to reach the tissues that need it most.

This is known as the Bohr Effect. And it means that when we over-breathe — taking too many breaths, breathing too fast, exhaling too much CO₂ — we actually reduce the amount of oxygen our cells can use.

The paradox of deep breathing

We’ve been told to “take a deep breath” when we’re stressed. And while slow, nasal, diaphragmatic breathing is genuinely beneficial — the emphasis on breathing “more” air misses the point entirely.

What we actually need is to breathe less, more efficiently. To slow down. To let CO₂ build to its optimal level so that every molecule of oxygen we do breathe in can actually be used.

What this means for you

If you’re experiencing low energy, brain fog, poor sleep, or feeling anxious without clear cause — your breathing pattern is worth examining. Not because you need more oxygen. But because you may be exhaling too much CO₂ to use what you already have.

The body is not a simple input-output machine. It is a system of signals, pressures and feedback loops. Breath is at the centre of all of them.

The goal was never to breathe more. It was always to breathe better.

Sources: Bohr, C., Hasselbalch, K., Krogh, A. (1904). Skandinavisches Archiv für Physiologie. / McKeown, P. The Oxygen Advantage (2015).