Before you start: Only do this test sitting or lying down somewhere safe — never in water, while driving, or standing somewhere you could fall if you feel lightheaded. Don't hyperventilate beforehand. Stop immediately if you feel dizzy or unwell.
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Ready
How it works
Click Start, take a comfortable deep breath, and hold it for as long as feels okay. Click Stop the moment you need to breathe again. Your time is measured live, compared against general benchmarks below, and your personal best is saved on this device so you can track it over multiple attempts.
This is casually known as the Stukel test or a simple breath-hold time (BHT) check — a rough, informal way to get a feel for your current breath control, not a measurement of lung capacity or function in the clinical sense.
What does my time mean?
Time
General category
Under 30s
Below average — common if you're out of practice, anxious, or new to breath-holding
30–60s
Average for most healthy untrained adults
60–90s
Good — better than typical, often seen in people who exercise regularly
90–120s
Very good — approaching levels seen in trained swimmers and singers
120s+
Excellent — trained divers and breath-work practitioners can hold for several minutes
These are informal, commonly cited reference points — not a validated clinical scale. Breath-hold time varies a lot based on lung volume, CO2 tolerance (which improves with practice), anxiety level, and whether you've recently exercised.
Frequently asked questions
Not necessarily in a medical sense. Breath-hold time mostly reflects CO2 tolerance and practice, not lung disease risk. Very short times aren't automatically a red flag, and very long times aren't automatically a sign of superior health — though regular practice can genuinely improve your CO2 tolerance over time.
It's almost entirely carbon dioxide buildup, not low oxygen. Your body's urge to breathe is triggered by rising CO2 levels in your blood, which is why breath-holding practice mostly trains your tolerance to that sensation rather than "expanding your lungs."
Yes, to a meaningful degree, through regular practice (common in swimmers, singers, and free-divers), improved cardiovascular fitness, and techniques like slow diaphragmatic breathing. Progress should be gradual and never pushed to the point of dizziness or blackout risk.
Mild lightheadedness can happen from the rapid CO2 and oxygen shifts, especially if you took a very deep breath first. If it happens, sit down, breathe normally, and let it pass. If dizziness is frequent, severe, or happens with normal breathing too, mention it to a doctor.
For most healthy people, a brief comfortable breath-hold is low-risk. It's not recommended for people with heart conditions, respiratory conditions, uncontrolled high blood pressure, or during pregnancy without a doctor's input first. Never do extended breath-holding in or near water alone.
Hyperventilating lowers your blood CO2 artificially, which delays the urge to breathe without actually increasing your oxygen reserves much. This can lead to blacking out from low oxygen with no warning signal beforehand — a genuinely dangerous combination, especially in or near water. Just take one comfortable deep breath, not several rapid ones.
Not a medical or diagnostic test: This is an informal wellness activity, not a measurement of lung function, lung capacity, or cardiovascular health. If you have breathing difficulty, chest pain, or a diagnosed heart or lung condition, talk to a doctor before trying breath-holding exercises.