Estimate the oxygen saturation healthy lungs deliver at a given altitude, and see whether your reading fits the environment.
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- Risk spectrum with your position marked
- Reference ranges from the original publication
- Shareable link, nothing stored
Scientific references
Why saturation falls with altitude
Air pressure drops with height, so each breath carries fewer oxygen molecules. Healthy acclimatized people compensate, but readings of 91 to 94 percent at 3000 meters are physiology, not disease.
Understanding your result
- Above 95 percent is the sea level normal zone
- 90 to 94 percent is expected at real altitude
- Below 90 percent needs attention anywhere, urgent with symptoms
Acclimatization rules
Above 2500 meters, climb sleeping altitude by no more than 500 meters a day and add a rest day each thousand. Headache plus nausea means stop ascending.
Who struggles
Fit and unfit people acclimatize at similar rates, while prior altitude illness, ascent speed and sleeping altitude predict trouble far better than fitness.