Performance-Enhancing Placebos: You Are What You Think You Eat

Imagine this: Thirty-two recreational runners, aged 18 to 55, watch a video explaining that super-oxygenated water provides up to 10 times more oxygen than tap water and thus improves running times. The runners then run three
5-Ks; the first is to get familiar with the indoor track and the next two to compare times after drinking 16 ounces of regular bottled water and
16 ounces of what was said to be super-oxygenated water.
The Moving Crew, writing in the Washington Post, reports on the results: 27 of the 32 people ran faster — an average of 83 seconds quicker —
after downing the alleged "super-oxygenated" water, even though it was actually regular tap water.
The study, commissioned by the American
Council on Exercise (ACE) and conducted by a clinical exercise physiology graduate student at the University of Wisconsin-La Crosse, also found that those who ran the first 5-K in under 20 minutes improved on
their bottled-water time by about 28 seconds during the placebo run vs.
142 seconds for those who took longer than 20 minutes, suggesting that less-practiced runners find it easier to influence performance with positive attitudes.
The Moving Crew also points out that even though some runners had better times  during the tap-water run, their
heart rates, perceived exertion and blood lactate levels did not differ
meaningfully from their scores during the bottled-water trial. The suggestion here, they say, is that the
body can make real biological adjustments — in this case, increasing
exercise tolerance — based on signals from the brain, even those based
on a lie. Read more from the Moving Crew.