How to Calculate Speed From VO2

A patient's speed and a treadmill's grade at a target heart rate determine VO2.

VO2 max describes how much oxygen a subject's blood can carry and use during exercise. A person with a higher VO2, also known as aerobic capacity or maximal oxygen uptake, is physically more fit--all other factors being equal. An accurate measure of subjects' VO2 requires that you measure their cardiac output and the levels of oxygen in their arteries and veins. But a formula approximately relates VO2 to a subject's speed when walking on a graded treadmill.

Instructions

1. Subtract from VO2 the resting oxygen consumption rate, in milliliters per kilogram per minute. If the resting consumption rate is 3.5, the typical rate, and VO2 is 15 milliliters per kilogram per minuter: 15 - 3.5 = 11.5.

2. Multiply 1.8 by the treadmill's grade, expressed as a fraction. Physicians use the coefficient 1.8 to define the significance of speed and grade when determining VO2. If the treadmill has a grade of 0.12: 1.8 x 0.12 = 0.216.

3. Add 0.1 to your answer. Physicians use the coefficient 0.1 to define the importance of speed, independent of grade, when determining VO2. 0.216 + 0.1 = 0.316.

4. Divide the answer to step one by the answer to step three: 11.5 / 0.316 = 36.39. This is the walker's speed in meters per minute.

5. Divide by 26.8 to convert from meters per minute to miles per hour: 36.39 / 26.8 = 1.36. This is the walker's speed.

References

• "Physical Activity Instruction of Older Adults"; C. Jessie Jones; 2005
• "Physical Medicine and Rehabilitation: Principles and Practice"; Joel A. DeLisa; 2005