Compounds and compositions for improving power output and oxygen efficiency

A method for improving oxygen efficiency by lowering the ratio of oxygen consumption over power output, the ratio represented by VO2/power, in a healthy subject, the method comprising administering prior to physical exercise and/or the onset of stress caused by such exercise to the subject a composition comprising hesperidin in a mixture of R- and S-enantiomers, wherein the R:S molar ratio of the mixture is between 1:2 and 1:5,

• and wherein the healthy subject is selected from a trained athlete, a moderately trained subject or an untrained subject.