VO2max is based on aerobic fitness.Small bursts of activity on a treadmill 4 minutes fast and 3 minutes slower, repeated 4 times for 4X4. It is used to measure one's fitness age. The Norwegian Institute of Science and Technology in Trondheim, Norway, has fitness age calculator on its website. Up tempo exercize one that increases your breathing and heart rate improves your VO2max. The key is exerting yourself vigorously three or four times a week.
Original article 5 minutes, gist 1 minute