Date: 3/22/22
Training Day: 107
Miles: 3 (treadmill)
Time: 42 min
Shoes: Xero HFS
Activity: Strength

How It Felt: Another easy run that felt great. I’m really digging going slow. The strength workout felt good, but the suspension push-ups kicked my butt!

Commentary: I keep doing iFit runs with Tommy Rivs, and he keeps talking about 80/20 running. I finally broke down and bought Matt Fitzgerald’s book 80/20 Running: Run Stronger and Race Faster By Training Slower. Perhaps I will take a break from the book I’m currently reading to dive into 80/20 Running…

Matt Fitzgerald has a website all about 80/20 running, and it even has a heart rate zone calculator. There are seven zones:

Zone 1	Very low intensity
Zone 2	Low intensity
Zone X	Moderate intensity rut
Zone 3	Moderate intensity
Zone Y	Gap between zones
Zone 4	VO2max intensity
Zone 5	High intensity/intervals

Supposedly a lot of recreational runners such as myself get stuck in Zone X on our easy runs. We run just hard enough to stress our bodies without any additional benefit over Zone 2 running. Zone 2 is the sweet spot for easy and long runs.

Out of curiosity, I wanted to see how much time I’ve spent in each zone during my training thus far (since the beginning of the year). My Garmin says my lactate threshold heart rate is 161 bpm, so I used that to calculate my 80/20 heart rate zones. I put my zones into Runalyze and it spit out some handy percentages:

Zone 1	9.2%
Zone 2	34.9%
Zone X	29.2%
Zone 3	18.8%
Zone Y	2.5%
Zone 4	3.3%
Zone 5	2.1%

Runalyze also made the nifty histogram you see above. As you can see, for the first ten weeks of training I didn’t spend nearly enough time in the low intensity zones. Week 11 looks a little better because on Thursday I finally committed to the 80/20 running.

I’m a wee disappointed that I didn’t learn about this stuff earlier in my 55k training. For the past 11 weeks I could have been building up a super solid base with low intensity running. I can’t help but wonder how much better my fitness would be if I’d been doing the 80/20 thing this whole time.

But having regrets never helps! All I can do is move forward with this new knowledge.

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