I thought this would be a relatively basic question, but my experiences are going against what I assumed. Googling for these terms has been unsuccessful.
I assumed that when your fitness increased, your lactate threshold would become higher because your body would become used to handling more lactic acid. Right now my fitness has never been better, but I'm noticing significant burning and increased effort when trying to maintain what I had previously calculated to be my threshold HR. For example, last year I would average 150 bpm on a longer ride, where this year I would feel like I'm putting in the same effort, but going faster, and averaging 135. Similar with run. Last year I TT'd at 178, where this year I did 161 (and again, went faster).
Could it be possible that with training, your threshold HR would go down significantly over one year? I have a few ideas.
1) I've been focusing heavily on endurance and I haven't pushed my HR high enough to maintain a high LT
2) My body is just more efficient now
3) Overtraining (which I'm leaning against, since I've been running much faster and longer than last year)
4) My recent weight loss basically tossed the rulebook out the window
5) STFU and just get some proper testing done
Now that I've typed it all out, I'm thinking 1, 2, and 4 are all contributing factors, and to just 5 after I've recovered from IMSG.
Any thoughts? :)
What was your cadence looking like throughout the efforts? I think that's going to tell you a lot as well.
My guess is that your cadence was slower in the 2nd effort, which is why your HR was lower but effort was the same...just an idea