from the latest review on HRV-guided training (full text here: apcz.umk.pl/QS/article/…):

“HRV-guided training improves aerobic capacity and endurance more efficiently than standard programs, even with fewer high-intensity sessions. It allows training during optimal readiness, prioritizes recovery when needed, reduces non-responders, and facilitates precise load regulation”

You can learn more about the history of HRV-guided training, here:

Plus, a few more thoughts about when to push, here: