My perspective is this. Any kind of resistance applied to a movement, whether it be resistance to a movement with your body externally or resistance to your breathing will cause a feeling of greater performance once the resistance is removed. I could see this causing your body to adapt to functioning with less oxygen and thereby improving it’s abilities when greater amounts of oxygen available. On the other hand, this is not allowing growth in the bodies pathways of receiving greater amounts of oxygen. However, being that it is an elevation mask, you would think that some people might think that it will help them in higher altitudes. The problem with this though, is that the percentage of oxygen in the air at those higher altitudes is less not the overall amount of air as with the mask. Definitely more research is needed.