BOLT score test
BOLT stands for Body Oxygen Level Test. You breathe normally, let a normal breath out, pinch your nose, and time how long it takes before your body first asks for air. Not how long you can last — how long until the first ask.
The timer opens on that protocol and places the result in the four bands Patrick McKeown publishes. Sit down first.
Opens with the BOLT protocol already set
- Hold starts after a normal exhale, not a full breath
- Stops at the first definite urge to breathe
- Scored against McKeown's four published bands
- Own history, kept apart from your CO2 baseline
The instruction on the timer is the BOLT one. The parent tool phrases the same measurement differently and stores it separately.
Press start when you are ready to sit still
Normal exhale, first urge, nose pinched
Three details decide whether your number means anything. The breath before the hold is a normal one, in and out through the nose — not a full inhale and not a forced empty. The nose is pinched so no air sneaks in. And the hold ends at the first definite desire to breathe.
That first sign is usually a swallow, a tightening in the throat, or the first twitch of the diaphragm. Push past it and you have measured something else. A hold to the breaking point is a different test with different numbers, and it belongs on the breath hold timer.
Four bands, and the gap between them
McKeown publishes four things, not five: below 10 seconds, 10 to 20, 20 to 30, and 40 seconds as the target. There is no published band between 30 and 40. Tables that print one have invented it, and the table on this page leaves the gap visible.
Buteyko Clinic publishes a five-band Control Pause table for the same measurement with different boundaries. The two disagree between 20 and 25 seconds, so mixing them produces a score that depends on which page you read. We use McKeown's.
The evidence is thinner than the popularity
Two studies have tested BOLT against performance and found nothing. A 2024 study of 49 elite speedskaters found no association with any Wingate or cardiopulmonary measure, and its authors write that the test has not been scientifically validated. A 2026 study of 28 active students found no link with maximal oxygen uptake or habitual activity.
The mechanism is shakier still. The one study that measured breath-hold time against end-tidal carbon dioxide directly found the correlation running the opposite way to the claim the test is built on. So this page will not tell you your BOLT score measures your CO2 tolerance. It measures time to first air hunger, which is a fine thing to track and a poor thing to interpret.
What it is good for
- Tracking yourself. The test repeats well — reported within-subject variation of about six percent on a one-month retest, and reliability coefficients above 0.94. Your own trend is the signal.
- Sizing a session. A low score on a given morning is a reason to run an easier table, not a reason to worry.
- Not ranking yourself. The bands are one author's published thresholds, not population percentiles.
- Not diagnosing anything. No score on this page says anything about a health condition, and nothing here is medical advice. If breathing is a problem for you, that is a conversation with a clinician.
McKeown's published bands, printed as published
Compiled 2026-09-04 from the BOLT bands on oxygenadvantage.com and The Oxygen Advantage (McKeown, 2015); the timer above starts after your normal exhale and stops when you press the button, which is the protocol these bands describe.
| Band | Published? | What the source says |
|---|---|---|
| Below 10 seconds | yes | The lowest band McKeown names |
| 10 to 20 seconds | yes | Roughly 3 to 5 seconds a week of gain reported early on |
| 20 to 30 seconds | yes | Around 20 seconds called good; typical for a regular exerciser |
| 30 to 40 seconds | no | No band published for this range |
| 40 seconds | yes | Named as the ideal for a healthy adult |
Four published bands and one real gap. The source moves from “20 to 30 seconds” to “40 seconds” with nothing in between, so the row for 30 to 40 on this page says exactly that rather than guessing a label.
Two more published figures worth having: McKeown reports a typical breathing rate of 8 to 10 breaths a minute at a BOLT of 40, and states that each five-second gain is noticeable. He also gives 20 seconds as a normal starting point for someone who already exercises at moderate intensity.
Where the bands stop being usable: as a comparison between people. Two peer-reviewed studies found no association between BOLT and exercise performance, and the mechanism the test is named for was contradicted by the one study that measured it. The bands are a published scale, not a validated one. Track your own line across weeks and ignore everyone else's.
Sources: McKeown P, How to Measure Your BOLT Score, oxygenadvantage.com; McKeown P, The Oxygen Advantage, William Morrow, 2015. Null results: Kowalski et al., Frontiers in Physiology 2024;15:1430837; Courtney & Cohen, Journal of Alternative and Complementary Medicine 2008;14(2):115-123.
Questions
- What is a BOLT score?
- The Body Oxygen Level Test: after a normal exhale, you pinch your nose and time how long it takes until the first definite urge to breathe. It is a comfort measurement, not a maximum breath hold.
- What is a good BOLT score?
- Patrick McKeown names 40 seconds as the ideal for a healthy adult and calls a score around 20 seconds good. He publishes four bands: below 10 seconds, 10 to 20, 20 to 30, and 40 as the target. There is no published band between 30 and 40.
- How do I do the BOLT test correctly?
- Breathe normally, take a normal breath in through the nose and a normal breath out, then pinch your nose and start the timer. Stop at the first definite urge to breathe. Do not take a full inhale, do not force the exhale, and do not push to your limit.
- Is the BOLT score the same as the control pause?
- The measurement is the same but the scales differ. Buteyko Clinic publishes a five-band control pause table whose boundaries disagree with McKeown's between 20 and 25 seconds. Pick one scale and stay on it.
- Does a higher BOLT score mean better CO2 tolerance?
- The evidence does not support that. The one study that measured breath-hold time against end-tidal carbon dioxide found the correlation running the opposite way, and two studies found no link between BOLT and exercise performance. It measures time to first air hunger.
- How often should I measure my BOLT score?
- First thing in the morning, once a day at most, under the same conditions. Test-retest variation in the same person is around six percent over a month, so a change smaller than a few seconds is noise.
Where to go next
- CO2 baseline test — the parent tool, and the number that sizes an equanimity table
- CO2 tolerance test — the other named protocol on this timer — a timed exhale rather than a hold
- Average breath hold time by age — the maximum-hold measurement, placed against published reference times
- CO2 tolerance explained — what the term covers and where the evidence runs out