Mhr should be calculated a. 20 minutes after an exercise routine. b. prior to an initial exercise routine. c. during an intense exercise routine. d. immediately following an exercise routine. 4

MHR or Maximum Heart Rate is the number of beats per minute of the heart which is usually estimated by subtracting one's age from 220. The proper way of calculating MHR is to get it immediately following an exercise routine. This is to ensure that the heart is pumping at its maximum when exhaustion is at its peak. It is usually tested in schools through the simple assessment called Step Test. 

The Step Test is where an individual steps up and down a step box for 3 full minutes and heart rate will be taken immediately after the test. The opposite of MHR is RHR, or Resting Heart Rate. This is best taken in the mornings when one just woke up to ensure that the heart is fully rested from a night's sleep.