*lthr

So I got a new toy, er, training tool earlier this week. It’s a BSX Insight bloodless lactate threshold sensor (it actually measures muscle oxygenation rather than lactate, but science…)

Anyway I did the running test protocol a few days ago which consists of running at specified paces on a treadmill through a series of 3 min stages of increasing intensity. Its a test to exhaustion so it’s over when you cry uncle or you get thrown off the back (not recommended). By default it creates 12 stages based on a short questionnaire (recent race times, etc). I was concerned looking at it because I didn’t think it would take me all the way to exhaustion and the last thing I wanted was to get to the end and it tell me insufficient data. I did indeed make it to the end, but it just started adding on additional stages (which were brutal by the way)- I managed to hold on through the middle of stage 14.

The results were immediately available. It put my LT1 (aerobic threshold or top of zone 2) at 161bpm which is much higher than I previously was using (150) and my LT2 aka LTHR at 180. This is actually where I had been putting the top of my zone 4, though I had previously believed my LTHR was down in the lower 170s. Basically the test is telling me what I already felt was “right” based on races and other intense workouts, but I had all my zones too low because they were mostly based on generalized calculators and field tests from ages ago. Apparently someone my age (43) normally has an LTHR about 10 bpm (or more) lower than I do.

It will be interesting to see what I do with this data now to hone in my training. In many ways I can now program workouts more in lines of best practices rather than “breaking the rules” like I felt I had to do with my flawed zones. I knew 180 couldn’t really be well into my VO2Max zone- I ran the last hour of the Indy Mini Marathon last year above 180 - it didn’t feel great, but it certainly felt sustainable to the end.

Also next week I’ll repeat the test protocol on the bike!