Jonathan is a 34 year old male whose heart rate varies little from rest to exercise. He has VO2 max ml/min/kg. His Dr referred him to the facility for exercise training and wants him to begin at an intensity between 40% and 60% of VO2 reserve. You have found that Mr. P walks comfortabl at 2.5 mph.
What treadmill grades would allow him to exercise at the desired intensity range??
Although you did not list the resting VO2, we can assume it is 3.5 ml/kg/min, and therefore his VO2 max is 10 times higher at 35 ml/kg/min. Next you would subtract your VO2 resting from your VO2 max like this: 35-3.5=31.5 ml/kg/min = VO2R (VO2 reserve). Next you would factor in the percent of VO2R you would like to train Jonathan. The target exercise range of 40-60% would be calculated by multiplying the VO2R while adding in the resting VO2:
(31.5 * .40) + 3.5 = 16.1 ml/kg/min
(31.5 *.60) + 3.5 = 22.4 ml/kg/min
We can divide the range totals by 3.5 to find METs for exercise prescription:
22.4/3.5= 6.4 METs
A speed of 3 miles/hour at a grade of 2.5 would average 4.6 METs. From this point, he could increase speed and grade up to 4 miles/hour and 4 respectively to average 6.4 METs.