Calculator created by Jeff Burmann, NSCA-CPT. Questions? Email Jeff
Formula from ACSM’s Resources for the Personal Trainer, 3rd Edition 2010.
Some information gathered from NSCA’s Essentials of Strength and Conditioning, 3rd Edition 2008 and NSCA’s Essentials of Personal Training, 2nd Edition 2012.
VO2max is the maximum amount of oxygen you can take in and utilize. Not all air taken in is used by the body. The more cardiovascularly conditioned you are, the higher your VO2max will be, thus the more oxygen you’ll be able to utilize with each breath. Finding VO2max is among the best measures of cardiorespiratory fitness. Each liter of oxygen utilized burns about 5 kcals so the higher the VO2max, the more energy you will require to exercise meaning you can burn more calories and get better more intense workouts. Striving for a higher VO2max is one of the best ways to improve all cardiovascular functions in the body which will improve your overall fitness level.
HRR (Heart Rate Reserve) is a helpful number needed to understand how hard you’re working during exercise. Since you cannot know how much oxygen you’re using up during exercise, and you cannot exercise at 100% all the time like the VO2max, using a pulse count is still best in a typical exercise routine. Finding your heart rate bpm and knowing various heart rate reserve percentages, you can know approximately how much oxygen your consuming because exercise intensities from VO2max to HRR are very closely related. 50% VO2max is equal to about 50% HRR, 75% VO2max = 75% HRR, etc.
For greater precision over VO2max / HRR relation, use the following equation to get target VO2 or VO2 reserve. VO2R = [(Intensity %) x (VO2max – VO2rest)] + VO2rest.
At rest, oxygen utilization is about 3.5mL ⋅ kg-1 ⋅ min-1 and is known as a “Metabolic Equivalent of Tasks” or MET. 1 MET is resting, so at 5 METs, the body is working 5x harder than at rest. 1 Met is also known as VO2rest. Normal healthy individuals typically have a VO2max of 25-80 or 7.1 to 22.9 METS.
For another perspective, here is a list of estimated METs for various activities.