Introduction to Glider Flying > Introduction to Glider Flying > Medical Factors Associated with Glider Flying > Hypoxia > Hypoxic Hypoxia

Although the percentage of oxygen in the atmos-phere is constant, its partial pressure decreases proportionately as atmospheric pressure decreases. As you ascend during flight, the per-centage of each gas in the atmosphere remains the same, but there are fewer molecules avail-able

Figure1-12. This illustration shows the symptoms of hypoxia and time of useful consciousness as altitude increases.

at the pressure required for them to pass between the membranes in your respiratory system. This decrease of oxygen molecules at sufficient pressure can lead to hypoxic hypoxia.