The most obvious use for such a device is for someone who will be participating in the Olympics at a high altitude, but has to train at home at a lower altitude. But it is also useful for…
Anyone about to embark on a marathon or race, to train their lungs to perform to the max. Anyone planning to climb or hike at higher altitudes than normal. Anyone who wants to strengthen their endurance for basketball, hockey, zumba, tennis or whatever sport you play. Even just for jogging in your neighborhood. Anyone wanting their treadmill or elliptical training to be even more effective.
These are two elevation training masks currently on the market:
