I’ve recently noticed that there will be nonlinear increases in my pace when I hit certain HR levels and I’m curious as to whether this signals that a certain threshold are crossed. For example, I often do progressive aerobic runs where I’ll increase my bpm by 2 or 3 beats a mile. My pace will pretty much increase very gradually and linearly until I hit a certain HR and then the pace suddenly jumps up and then increases linearly again after that.
I’ve also noticed something similar during high tempo/low anaerobic runs. Yesterday, I did a 5k and let my bpm increase linearly about 6% from beginning to end. For the first two miles, my pace only increased by about 3% but it increased by about 5.6% from mile 2 to 3 after crossing about 92% of max HR.
Has anybody else noticed this? Does this mean anything or am I just on a fishing expedition?