There is no discipline in repeatedly destroying the instrument you depend on.

Wearing yourself down repeatedly is not rigour. Everything you want to do depends on one body and one mind, and treating them as expendable in service of the work eventually removes your ability to do the work at all. There is a version of discipline that includes care for the instrument, and it produces more over any period long enough to matter.

Ask what you would do if you were coaching someone you cared about at your current pace. Then extend that same standard to yourself. The advice you would give them is usually the accurate one.