Scientific studies have shown that the normal body reacts negatively to lack of oxygen in the air. However, well conditioned athletes are being trained in rooms or chambers called Hypoxic rooms and chambers to enhance their bodies physiology and ability to perform in low oxygen conditions. The reasoning is that the human body requires oxygen to perform cardio-respiratory functions such as walking, running, canoeing strokes and all kinds of muscle movement.
My experience is that at 3000 m oxygen level (16%), my body feels like I am burning off 30 % more energy to maintain the same speed of running. So, in effect, my body is improving its physio-kinetic ability and becoming more productive to produce the same output (running speed) for lesser ambient (16%) atmosphere. Hence over time in this special environment, my body will adapt to the reduced oxygen and perform. The longer time I am exposed to this environment, 16% will be the 'new normal' and I will be able to run at a good speed like I used to run when I am at ambient sea level conditions or 20.9% oxygen.
Once the air is set or returned to normal, meaning O2 is 20.9 %. My body will feel it is supercharged and full of energy. Its as if the parachute / backpack which was open on my back has been cut loose. Hence my running speed will be phenomenal.
This is the theory the sports scientists employ to manage, monitor and condition their elite athletes. Its called Hypoxic condiitoning. My company installs such systems worldwide and we are doing projects from Middle East, to Singapore to Australia.
The future belongs to science. The legitimacy is established by the sporting bodies. So more and more countries will employ such modern techniques to attain sporting glory, trophies and medals for their countries. My business is to provide such equipment to meet those goals. The playing field has never been so exciting.