For a successful trekking or climbing expedition, a fast adaptation to altitude is key. A good fitness is also important for achieving the objective, but it will unfortunately not help for adapting to altitude, since the body need time to adjust to the high altitude. There are two ways to adapt, to stay at a certain altitude for a few extra days (which is usually not possible with planned trekking programs) or acclimate beforehand. The basic principle of all acclimatization programs is to gradually expose the body to air with less oxygen, which encourages it to adapt. This basically means a more efficient intake and transport of oxygen in the body.
Altitude training allows you to start the acclimatization even before going to the mountains. This is especially useful for those who do not have time to acclimate on the location.
For general acclimatization, an IHT, which is used as a system for testing the response to altitude and later for the acclimatization program to an altitutde of 6,500 m, is recommended. Altitude sleeping is recommend to climbers, serious trekkers and anyone going to extreme altitude. Start to use the program at least a month prior to your expedition or stay at an atitude.