There is no doubt that extra oxygen does improve your exercise performance. Conversely, a lack of oxygen (as an altitude) can have a detrimental effect on aerobic exercise & performance.

~Tony Lychalat, MSC Sports Med (top sports scientist & coach to leading athletes. (Zest, 2000)

Extra oxygen enables you to recover more quickly from exertion. It allows someone to train and then exercise again.

-Dr. John Brewer, Head of Sports Science at Lilleshall Human Performance Centre (Health and Fitness, 1999)

In 1996, M.C. Moss and A.B. Scholey, neurophysiologists studying about oxygens effect on learning, conducted an experiment on 12 word-memorizing ability to 105 people at the age of 18~21, and indicated that the group treated with oxygen for a minute had shown increased memory by 91% in 10 minutes and by 41% in 24 hours compared to its counterpart. (Psychopharmacology 124: 255- 60)

Big cities have poor air - there has been a real decrease in the amount of oxygen in the air

- Dr Richard Dixon, Head of Research, Friends of the Earth, Sunday Herald, 1999

Oxygen is essential to body and brain function, and the more oxygen available to the system, the better it will function.

~Dr. Robert Mazzero (Medicine and Science in Sports and Exercise 1999)

"Insufficient oxygen means insufficient biological energy that can result in anything from mild fatigue to life threatening disease. The link between insufficient oxygen and disease has now been firmly established.

~ Dr. W. Spencer Way , Journal of the American Association of Physicians