Just reading your other replies, I’m curious: did you test your heart rate or did you use a calculator? The 220-your age is completely incorrect for most people

Just reading your other replies, I’m curious: did you test your heart rate or did you use a calculator? The 220-your age is completely incorrect for most people. I prefer a lactate test, rather than max HR, because it’s “easier” for me to induce. Basically, run a 30 minute, even paced, maximal effort. You then calculate your LT by removing 5% off the pace and HR averages you got. The important part is the pace must be reasonably even and also maximum effort. So, it’ll feel easy to start and by the end you’ll want to vomit. If you’re lucky enough to live near a Park Run, you can do this a few times instead to learn your max effort pacing and work out Z2 from that.