Box breathing, sized to you
Breathe in, hold, breathe out, hold, in four equal sides. Huberman's twist is to size each side to your own exhale, not to a number from a poster.
TimeTwo to three minutes, once or twice a week to build the skill.
Safety first
- Never do breath holds in or near water, or while driving or operating machinery.
- Stop and breathe normally if you feel dizzy, lightheaded or anxious. A hold should feel easy, never a struggle.
- Skip the timed exhale if it makes you anxious. For some people, paying close attention to carbon dioxide and breath can set off panic. If that is you, choose the physiological sigh instead and talk to a health professional.
- If you have asthma, COPD or any heart or lung condition, check with a health professional before you start.
- This is a wellness practice. It does not diagnose or treat anything.
Never do breath holds or fast breathing in or near water, or while driving. Stop if you feel dizzy.
How to do it
- Find your number, using a test from Brian Mackenzie that Huberman describes. Breathe normally for four or five breaths. Take one full breath in through your nose. Then breathe out through your nose as slowly as you can, and time it. Stop when your lungs feel empty. This is not a breath hold. That time, in seconds, is your number.
- Choose a side length that feels easy. Use your number if it is short. If it is long, start with 4 seconds and build up over weeks. The holds should never strain.
- Breathe in through your nose for one side. Hold, relaxed, for one side.
- Breathe out for one side. Hold, relaxed, for one side.
- Repeat for two to three minutes. Test again every week or two and let the sides grow slowly.
Why carbon dioxide comes into it
Huberman’s argument starts with a surprise. Carbon dioxide is not just waste. In his words, it “changes hemoglobin’s shape to help liberate bound oxygen” into your cells. He says most people breathe 15 to 18 times a minute where about 12 would be calmer, and that over-breathing lowers carbon dioxide, which can leave you edgy and scattered even though you are taking in plenty of air.
If that is right, then calm is partly the skill of staying comfortable with a little more carbon dioxide. That is what the timed exhale measures, loosely, and why he asks you to size the box to your own number instead of copying a generic count.
Box breathing and the sigh do different jobs
Use the physiological sigh when you need to come down fast. Box breathing is steadier. It balances rather than sedates, which makes it a good way to settle scattered attention before focused work, or before a meeting.
In the Stanford study, box breathing was one of the practices compared. Cyclic sighing did best on mood and breathing rate. So box breathing is not the strongest tool for stress, and the Club does not pretend otherwise. It is a skill you may enjoy.
When your number is not right
Your number is only as good as the test. If you cut the exhale short because you felt anxious, your box will be too small. If you strained, it will be too big. Stay relaxed, and let the number be what it is.
The numbers are a rule of thumb, not a measurement of health. We do not offer this test as a medical check.