Using Heart Rate and the related VO_2max/peak method vs Heart Reserve and related VO_2Reserve method

When calculating the percentage of exertion intensity a person will do in an ExRx, two approaches are available, Heart Rate which does not consider resting heart rate in its calculation -- OR -- Heart Rate Reserve which does consider resting heart rate into its calculation.

• My preference, and for this class, we will use the Heart Rate Reserve (HRR) method and its related VO₂ calculation, VO_2Reserve method. The HRR method has a few more calculation steps, but allows us to use the same % intensity for both %HRR and %VO₂reserve, this is not true for the Heart Rate Method. This ability to use the same % intensity is extremely helpful when calculating calorie use in a ExRx program.

  • Example of Heart Rate differences using Heart Rate Vs Heart Rate Reserve for a person 20 yrs old with a resting heart rate of 70, a VO_2max/peak of 50 mL· kg^-1·min^-1 and will be exerting at 50% intensity.
    •  Heart Rate  = Max heart rate (220 - age) * % Intensity  = (220-20)*.5 = 100 bpm when exerting at 50% intensity
       
    • Heart Rate Reserve = ((Max Heart rate - Resting HR) * % Intensity) + Resting HR = ((220-20)-70))*.5)+70 = 135 bpm exerting at 50% intensity.
       
      **As you see above, using different methods leads to different exerting heart rates**
      **Whatever method you use to calculate exertion intensity, should be the same used in your other ExRx conversions.**
       

• Example of VO₂ differences using VO_2max/peak  and   VO_2Reserve for a person 20 yrs old with a resting heart rate of 70, a VO_2max/peak of 50 mL· kg^-1·min^-1 and will be exerting at 50% intensity.
  • VO_2max/peak  = VO_2max/peak * % Intensity = 50*.5 = 25 mL· kg^-1·min^-1 exerting at 50% intensity.
       
  • VO_2Reserve (VO₂R) =  ((VO_2max/peak - Resting VO₂) * %Intensity) + Resting VO₂ = ((50-3.5)*.5)+3.5 = 26.75 mL· kg^-11·minn^-11 exerting at 50% intensity.
     
    **As you see above, using different methods leads to different exerting heart rates**
    **Whatever method you use to calculate exertion intensity, should be the same used in your other ExRx conversions.***