On rides of long duration, I find that keeping power and heart rate below certain thresholds results in a system-wide ability to maintain lower heart rate and perceived effort. Going over those thresholds (burning a match, going into the red, etc.) seems to prime the body for higher heart rates, even after a normal heart rate has been attained by reducing output. The resulting effect is that I ride long events faster by avoiding even short-length high intensity. It’s almost like those one or two high efforts add a multiplier to my heart rate.
Can anyone point to some good resources, or offer some physiological explanation as to why heart rate increases seem to come quicker after going into the red?