Air pressure vs. altitude: https://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html https://www.engineeringtoolbox.com/air-altitude-pressure-d_4...

Air pressure vs. altitude: https://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html https://www.engineeringtoolbox.com/air-altitude-pressure-d_4... If I remember correctly, commercial aircraft are pressurized at about 8,000 ft. 25,000 ft is 5.45 psi, resulting in about 5.5 psi overpressure if you are depressurized. You might have a hard time, and you can injure your lungs doing that. The time until you pass out will depend on your oxygenation situation before the loss of pressure, general health and fitness, activity level (panicking would be a bad idea), and a bunch of other things.