Part 1 of this series.
The MAF HR number is 180 minus the age. How does this compare to the 220 minus age times 75%-85% often used?
- 220 – age (58) = 162 bpm max
- 75% of 162 = 121.5 bpm
- 85% of 162 = 137.7 bpm
MAF 180 Formula
- 180 – age (58) = 122 bpm (maximum aerobic HR)
- 122 – 10 = 112 bpm (bottom of range)
Interesting how close the MAF max of 122 and the 75% number of the 220 formula of 121.5 are so close.
Here’s another article with various methods (Matt Danielsson. How To Calculate Your Heart. Rate! bodybuilding.com December 09, 2014 ).
When you’re doing cardio to burn fat, you want to stay in the range of 65%-70% of your maximum heart rate. If the goal is to increase stamina and aerobic capacity, you aim for 85%.
Harvard’s Men’s Health Watch published an explanation last year that sheds some new light on this matter. A couple of Colorado scientists did some exercise test reality checking and reviewed the results of 18,712 men and women of all ages. Based on the this real-life data they came up with a new formula:
Maximum heart rate
= 208 – (0.7 x age in years)
Using the 208 formula – 208 * (0.7*58) = 167 bpm
I have been at that rate many times in CrossFit workouts.
The cardio range is 65%-70% of that number or 109-117 bpm. The “stamina/aerobic capacity” number is 142 bpm.
Which Number to Trust?
I actually know from my VO2max testing and the measurements of RER exactly where my heart rate was at during the ramp up for the top end where my RER was still 0.7. And that heart rate was at 120, so this matches the MAF number quite nicely.
Why does it matter to me?
I am a Low Carb eater. That means my body spares the glycogen stores for glucose production for the brain. My bod burns fat as its normal fuel. That also means that my diet is optimized for endurance activities and against activities which rely on glycogen stores. So I have a choice. I can continue to suck at the activity I am doing or change my diet. And there’s no way I am changing my diet.