since the resmed s8 escape has patient adjustments for altitude, sometimes i increase the pressure by increasing the altitude. there are four altitude settings. 0-2000 ft, 2000-3999 ft, 4000-5999 ft, and 6000-7999 ft. apparently air is thinner the higher you go so to compensate for the thinness of the air you have to up the pressure. i believe since the air pressure is lower at high altitude, compressing the air faster will result in a pressure that is equal to the programmed sea level pressure. since i live at sea level, this gives me 3 additional increments of pressure by changing the altitude settings. I definitely notice a difference. and the difference makes a difference in positive airway pressure clearance. could it be dangerous to adjust the pressure one step up or two steps up. I am not sure. i dont think it would, three steps up maybe. certainly dropping the pressure down might make a dangerous difference. thats unless you have lost weight and need less pressure to keep the airway open. if for example you lived in santa fe, which is 7250 ft. you might have your setting set at the 6000-7999 ft level. theoretically you could adjust downward 3 settings, say , for if you were visiting new york at sea level. unless you adjusted down you would be getting quite a blast of air and it would be a chore to exhale. but if you were in santa fe and you adjusted down while you were there, you might cause a situation where you defeat the cpap. thats unless the cpap were adjusted too high and if you adjusted down one level you could deflate the tire so to speak. what i am telling you is this is the cheap and dirty way to adjust the cpap but with limited ability. if you live in iowa for exampl and the altitude is, idont know i am just guessing 3500 ft, you are on the second level. then you have the luxury of adjusting down to sea level or up two levels. these people can adjust up or down depending where you live. so to recap. depending on where you live you can adjust up 3 levels and down 0 levels, or up two levels and down one level, or up one level and down two levels, or down 3 levels and up 0 levels. knock yourself out. but ask me some other questions. i know everything.