Conditions:

(1) The person is walking at a constant speed of at least 50 meters per minute.

(2) The equation can be used at speeds over 100 m/min if the person is truly walking.

oxygen uptake in mL per kg per min =

= (resting oxygen uptake) + (horizontal oxygen uptake) + (vertical oxygen uptake)

horizontal oxygen uptake =

= 0.1 * (walking speed in meters per minute)

vertical oxygen uptake =

= 1.8 * (walking speed in meters per minute) * (grade)

where:

• The resting oxygen uptake is 3.5 mL per kg per min (1 MET).

• The 0.1 factor in the horizontal oxygen uptake is the regression constant for converting m/min to mL per kg per min.

• The 1.8 factor in the vertical oxygen uptake is the regression constant for converting m/min to mL per kg per min.

• The grade is the percent incline expressed as a decimal (for example, an X% incline is expressed as 0.0X).

• The vertical grade = 0 if (a) the walking is done on a level surface, (b) the person starts and ends walking at the same point.