A “good” VO2 max depends on age and sex, but for many healthy adults a relative score around 35–55 mL/(kg·min) is typical, with higher values generally reflecting better aerobic fitness. Untrained healthy men often fall near about 35–40 mL/(kg·min) and untrained healthy women near about 27–31; elite endurance athletes can exceed 70–90. Scores are usually expressed as milliliters of oxygen consumed per kilogram of body weight per minute and decline with age if training does not keep up.
Source: VO2 max — Wikipedia