Morning resting heart rate and heart rate variability right after waking up for cardio system.

Grip strength for central nervous system.

Bar velocity at a fixed weight for muscles.

Those 3 systems are capable of separate independent stress and recovery cycles and need to be individually monitored.

You say more breaks but I'm training more now because I'm doing a kettlebell day in addition to my barbell day. It doesn't take long but it is hard as hell.