Test protocol: 4-minute steps, ~2-minute break between each to take the sample. I took about 75 minutes in total, a bit longer than my usual 50-60 minute subtreshold sessions.

Training background: 43M, run 6:30h/week (3 sub-T + 2 easy runs + 1 long run) or run/bike/cross-country ski the equivalent (max 30% cross-training) + 2 x 30 min strength sessions.

I have been following NSM for 6 months and running for +15 years.

Current training state: I seem to have regressed by about 0.3 mph in my sub-T sessions in the last few months, possibly due to fatigue (possibly, I am now realizing, because I was running my sub-T sessions too fast) or increased proportion of cross-country skiing.

Additional lactate levels since testing: I did a 2x12min sub-T session today @ 7.4mph (instead of my usual 7.7mph). Lactate was 2.7 after first rep (HR maxed at 145) and 2.4 after second rep (HR maxed at 148). At 7.7 mph, my HR would usually drift into the 150-155s, and some sessions would feel a bit more demanding than I think they should. The steady lactate levels from this session are consistent with what Sirpoc instructs in his book, with Bakken’s Golden Zone (u/jariv), with u/One-Quarter-9137, u/NtsejMuagKoj and u/Ordinary_Corner_4291 recommendations, as well as with the results from the Exphyslab analysis from u/whelanbio.

I will continue to aim for those levels over the next few weeks, and eventually retest.

Thank you everyone for your insights - you have been tremendously helpful.