If you live up in the mountains, you know that the air is much thinner than it is closer to sea level. You might be used to it, but there is still less oxygen available to breathe in. That also means less oxygen that an oxygen concentrator has to work with. Oxygen concentrators must be strong enough to operate at higher elevations, so you would need one that has a higher maximum operational elevation.
You might also want to go hiking or take a trip up into the mountains, but maybe your lung capacity isn't as strong as it used to be. You should first get the advice of your doctor before you do anything strenuous is you have health issues, but an oxygen concentrator might be the best way to stay healthy.
The following oxygen concentrators all have a high maximum operational elavation, which means it will continue to give you the same high purity of oxygen, and there won't be a strain on the machine. They are also approved by the Federal Aviation Administration for use on a United States flight, and are all great for traveling. Of course, these elevation limits only count if you are outside of an airplane.
13,000+ Feet Above Sea Level
The Sequal Eclipse 5 maximum operational elevation is 13,123 feet above sea level. It also allows you to use as much as 3 LPM of continuous flow oxygen, and as much as 196 ml/min of pulse dose oxygen. One of the best portable models to take with you on any trip. The battery duration is also one of the best out of the bigger portable oxygen concentrators.
The Sequal Equinox has the same settings as the Eclipse series, along with the same features, with even more. They also feature the AutoSAT technology, which is even more useful at high elevations. The AutoSAT feature helps to release the pulse dose at the precise moment that you need it during your breathing cycle. You can get even more out of your oxygen therapy, even at such high altitudes. The Equinox only weighs about 15 lbs.
The DeVilbiss iGo is another robust portable oxygen concentrator with a maximum operational elevation of 13,123 feet above sea level. It weighs the same as the Eclipse, and has the same great range of continuous and pulse dose flow settings.
10,000 Feet Above Sea Level
The Invacare XPO2 is down a tier when it comes to high elavation use. It caps out with a 10,000 feet above sea level maximum operational elevation. It's also very lightweight and only weighs 6 lbs with the battery. It has the capacity to supply up to 900 ml/min of pulse dose oxygen, and has 5 settings.
The AirSep Freestyle 3 is another one that falls in this category, and it's one of the smallest portable oxygen concentrators. It can put out as much as 332 ml/min of pulse dose oxygen and is 4.4 lbs. You can get the external battery pack for more battery duration.