HR and power/pace mismatch

I have a problem with how the HR zones calculated by 8020 from threshold pace correspond to HR. Basically my HR for activities near threshold matches well with the threshold power and pace as measured from recent 10k tests performed with a Stryd pod. However, when moving to lower intensities my HR is much higher than the zones calculated by 8020 relative to threshold HR. I have made a plot of my pace vs. HR and the zone levels obtained from 8020 which can be found here: https://i.imgur.com/Co8NT3N.png

The issue seems to be that my HR enters Zone 2 very early and flattens out towards threshold, instead of what the 8020 zones predict which is that HR increases rapidly when moving towards threshold. This makes zone 2 very tricky because the pace range that covers it is quite different from what is expected. For example if I run at 6min/km then my HR will settle at about 150 depending on conditions, which is right in the middle of zone 2. However, if I run just 15 s/km faster, then I’ll end up north of 165 bordering on zone 3, while if I need to run 40s/km slower or so to end up in zone 1. According to the 8020 zone calculator I should be able to run 5:15min/km before entering zone X. If I tried to do that I would be running at an HR of 170-175, just below threshold.

I’m a newer runner, having run for approximate 18 months, so I would expect that my aerobic system is quite poorly developed. I am also quite slow, only being able to run 10k in 44:40.

What’s going on here, and how do I best adjust for this in training? Do I slow down my aerobic training accordingly and keep the higher intensities where they already are?

• This topic was modified 3 months, 3 weeks ago by 8020guy.
• This topic was modified 3 months, 3 weeks ago by 8020guy.