After a gruelling 12 hour shift (stop giggling at the back!) I donned my running gear and headed for home. Around my chest was my Heart Rate Monitor (HRM) and the plan was to run at a certain effort.
The theory is that different heart rates produce different effects. To simplify the situation, heart rates are split into a number of zones based on one’s maximum heart rate.
Now it gets confusing. There are a number of methods for calculating these zones.
Firstly is the matter of Maximum Heart Rate. Ideally this should be measured. There are, however, a few guesstimates. The simplest is to subtract your age from 220. Another uses 214 – age x 0.8.
Now to determine the zones, some methods use this Maximum Heart Rate as is while some take into account one’s Resting Heart Rate (which is a basic measure of fitness).
Whichever method has been used so far, percentages of this Heart Rate can be calculated. Using different methods, I came up with many different numbers …
Whichever method is chosen, there is further confusion as to which percentage band is best for fat burning. Most plumb for somewhere between 60% and 70%. Using the suggested percentages corresponding to the methods used above gives me fat burning heart rates of between 98 – 114 beats per minute (bpm) to 105 – 134 bpm.
The two tracking apps that I use, Endomondo and Garmin Connect, calculate my fat burning zone as 118 – 129 and 116 – 130 respectively.
Which do I use?
The majority put the upper limit around 129 bpm, so for now, I’ll use that. The lower limit, I don’t think I need worry about as I can see me needing to slow down rather than having to run faster.
Back to the run. I ran the most direct route from work, firstly along the canal, then a couple of miles on the road before hitting the Cole Valley Cycleway. IThe 6 mile run finished with another mile or so on the road. I tried to keep my bpm below 130 (see below) …
Not particularly clear, but after a bit of getting used to the pace I needed to keep below 130, the red line is fairly level. Looking at which zone I ran in (according to Endomondo) gives this …
So, making lots of assumptions, I seem to have got it about right. I think !