Pulse oximeters

["aux vaches"]

flying unpressurised above 10,000' you will be hypoxic so you need to know how much hypoxia is normal - the red line on the graph shows the rough relationship between oxygen saturation level and increasing altitude (5000m in Denver they run around or below 90%) above 6,500m sats bottom out at around 60-65% (compensatory hyperventilation) So you will need to figure what is normal for you at height so you can then spot a sudden significant difference (if you're still conscious !)