The benefits of aerobic exercise are realized when you are operating within a particular range of your aerobic capacity, which is based on VO2 max. Since in general that is hard to calculate, the easier method is by using your heart rate.
There are two methods. Both of them start by calculating your MHR (Max Heart Rate) as 220 minus your age. So for me, thats about 188 BPM (beats per minute).
The simple method simply takes a percentage of that. If you wanted to know your 50% heart rate, just multiply MHR by 50%, so in my case that would be 188*0.50 = 94 BPM.
Another method which is generally recognized as a more accurate one, first subtracts your RHR (Resting Heart Rate), takes a percentage of the remainder, then adds it back to the RHR. So in my case, assuming RHR=70, that would be (188-70)*0.5 + 70 = 129 BPM. Quite a big difference from 94 BPM!
The interesting thing is, at lower heart rates, more of the calories you burn are coming from fat, rather than carbohydrates. This is the reason that I use brisk walking as my aerobic exercise, instead of jogging. In my current physically unfit state, jogging would put me way above the aerobic heart rate range!
Here are my calculations....
220 - age = MaxHR
MaxHR - RestHR = HRR (Heart Rate Reserve)
Min and Max for Fat Burning
(85% of calories from fat)
min = RestHR + 50% of HRR
max = RestHR + 70% of HRR
Max for Aerobic
(50% of calories from fat)
= RestHR + 80% of HRR
Max for Performance
(15% of calories from fat)
= RestHR + 90% of HRR
Based on age=32, RHR=70:
min = 129
fat_max = 153
cardio_max = 164
perf_max = 176
DNE = MaxHR = 188
I really should stay below 153 for fat burning or 164 for cardio. I guess that means when it goes above 164, I need to stop talking and slow down to a snails pace to let my heart rate go down.
Since heart rate is very important, I bought a
Timex Ironman Triathlon Digital Heart Rate Monitor # T5D521
- About.com - The Truth About the Fat Burning Zone - Your Target Heart Rate
- TheWalkingSite.com - Your Best Training Tool - Target Heart Rate