All water that has been exposed to oxygen is oxygenated, but some water bottlers have increased the levels of oxygenation with oxygen gas. There are athletes who consume this type of water with the idea that it might improve athletic performance. A study published in the Journal of the International Society of Sports Nutrition looks into the subject.
Experienced male runners drank 3 bottles of oxygenated water during a 30-minute rest period, another bottle while running a 5,000 meter time trial and 2 more bottles during 30 minutes of passive recovery. Compared to runners who got a placebo, runners who drank oxygenated water experienced faster lactate clearance during recovery. There were no differences in time trial performance or muscle tissue oxygen saturation.