An extensive literature review was performed of studies where VO2max was measured directly in healthy, untrained subjects in the USA, Canada and 7 European countries to establish absolute (L/min) and relative (ml.kg-1.min-1) VO2max norms in males and females aged 6-75 years. Mean norms (L/min) in males show an increase from 1.0 L/min at age 6 years, to 2.0 and 3.4 L/min at ages 12 and 18 years, respectively, after which they decline with age to 3.2, 2.7, and 1.6 L/min for ages 30, 50, and 75 years, respectively. The corresponding values for females aged 6, 12, 18, 30, 50, and 75 years are 0.9, 1.8, 2.2, 1.8, and 1.1 L/min, respectively. Sex differences in relative VO2max are smaller than the above. Mean values for males for the above age groups are 47.5, 50, 48, 35, and 25 ml.kg-1.min-1, respectively, with corresponding values for females of 42.5, 44, 41, 28, and 17.5 ml.kg-1.min-1, respectively. These norms (L/min) are slightly lower than Robinson's 1938 data on males; they are only 1.5% lower compared with Astrand's adult males norms; but 2.5 to 10% lower than Astrand's norms for adult females. Present norms (ml.kg-1.min-1) for middle aged and older women are 25% lower than the corresponding Astrand's norms.