Heart Rate Reserve

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.

1 Calculating Heart Rate Reserve

The calculation to work out %HRR is (HR_ex – HR_rest)/(HR_max – HR_rest), where HR_ex is the exercise Heart Rate. For example a HR_max of 180, a HR_rest of 40 and HR_ex of 140 would be (140 – 40)/(180 – 40), which is 71%.

2 Why %HRR rather than %HR_max

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.

3 See Also

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