Salta al contenuto
← Back

⏱️ Body Oxygen Level Test

BOLT Score Test & Calculator

Measure your carbon dioxide tolerance and functional breathing efficiency. Time the gap until your first natural urge to breathe — not a test of willpower.

Exhale-Hold Assessment

0.0

Ready

Rules for an accurate BOLT score:

  1. Breathe normally through your nose for 1 minute.
  2. Take a normal, gentle exhale and pinch your nose.
  3. Tap Start and hold until the very first involuntary urge (throat swallow or diaphragm twitch).
  4. Tap Stop and release nose: your first breath in must be completely calm. If you gasp, you held too long!

Your Breathing Baseline

Take the BOLT test to see your score

Unlike general breath-holding which tests mental endurance, the BOLT score directly tests your body's sensitivity to carbon dioxide (CO2).

Under 10 secondsSignificant Breathing Dysfunction
10–20 secondsBelow Average / Compensated
20–30 secondsGood Functional Baseline
30–40 secondsHigh Athletic Stamina
40+ secondsGold Standard / Optimal
Best BOLT: — | Stored locally on device

What is the BOLT Score?

The Body Oxygen Level Test (BOLT) is a standardized assessment of respiratory health, developed by Patrick McKeown in The Oxygen Advantage and rooted in the physiological principles of the Buteyko Breathing Method. While maximum breath-holding measures willpower and oxygen deprivation tolerance, the BOLT score measures your sensitivity to carbon dioxide (CO2).

How Carbon Dioxide Controls Your Breathing

Most people assume that our urge to breathe comes from low oxygen. In reality, the primary chemical trigger for breathing is the buildup of arterial carbon dioxide. When arterial CO2 crosses your personal chemoreceptor threshold, your brainstem sends involuntary contraction signals to your diaphragm and intercostal muscles.

A low BOLT score (under 20 seconds) indicates low CO2 tolerance: your brain triggers panic and hyperventilation at minor CO2 increases. A higher BOLT score (30–40 seconds) means your cells comfortably buffer CO2, allowing more oxygen to be released to active muscles and organs via the Bohr Effect.

Signs of a Low BOLT Score (< 20s)

  • Breathing through the mouth during sleep or rest
  • Frequent sighing, yawning, or chest breathing
  • Disproportionate breathlessness when climbing stairs
  • Waking up with dry mouth or brain fog

Benefits of a High BOLT Score (30–40s)

  • Effortless nasal breathing during endurance workouts
  • Deeper, more restorative parasympathetic sleep
  • Lower resting heart rate and higher HRV
  • Greater mental resilience during acute stress

How to Improve Your BOLT Score by 5–10 Seconds

Improving your BOLT score takes consistent daily practice. The single most powerful intervention is 100% nasal breathing 24/7: at rest, during sleep (using mouth tape if necessary), and during light cardiovascular workouts. You can also train with structured breath holds using our CO2 apnea tables and box breathing exercises.