Heart Rate Reserve (HRR)

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

Heart Rate Reserve (HRR) is the difference between your Maximum Heart Rate (HR_max) and Resting Heart Rate (HR_rest). Exercise intensity can be evaluated by comparing 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 HR_ex of 140would be same %HR_max, but one is at 64 %HRR and the other is at 71 %HRR. However, for HRR to be of value, you have to test your HR_max, as it cannot be calculated. Most Heart Rate Monitors will display your %HRR if you input your HR_max and HR_rest.

See Also

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