Heart Rate Reserve (HRR)

A simplified chart of heart rate against exercise intensity showing Maximum Heart Rate, Heart Rate Reserve, Resting Heart Rate, Orthostatic Heart Rate, and Heart Rate Deflection.

Heart Rate Reserve (HRR) is normally calculated as the difference between your Maximum Heart Rate (HR_max) and Resting Heart Rate (HR_rest). Exercise intensity can be evaluated by calculating your heart rate as a percentage of HRR. The calculation to work out %HRR is (HR_ex – HR_rest)/(HR_max – HR_rest), where HR_ex is the exercise Heart Rate. So a HR_max of 180, a HR_rest of 40 and HR_ex of 140 would be (140 – 40)/(180 – 40), which is 71%. Using %HRR is better than a percentage of HR_max, as it reflects the relative intensity more accurately. For example, if two athletes both have a HR_max of 180, but one has a HR_rest of 40 and the other 70, at a HR of 140 they would both have the same %HR_max, but one is at 64 %HRR and the other is at 71 %HRR. While HRR is a good way of looking at effort and intensity, but there are two issues to be aware of.

1. For HRR to be of value, you have to test your HR_max, as it cannot be calculated. Calculating HR_max is a mistake that can lead to misleading views of effort.
2. I believe we should use the Orthostatic Heart Rate (HR_orth)which is the Heart Rate when standing rather than HR_rest, as HR_orth is typically 10-15 beats higher than HR_rest, which is enough to skew the relative effort percentage.

Most Heart Rate Monitors will display your %HRR if you input your HR_max and HR_rest.

See Also

• Maximum Heart Rate
• Resting Heart Rate
• Pulse Oximeter
• Heart Rate Deflection