I know the consequences. It's just that I don't want to get old without knowing the limits of my potential.
His dad tells him that they drive heavier and heavier trucks across each bridge until it falls down. Then they weigh the last truck and rebuild the bridge.
Perhaps you, unlike these imaginary bridge engineers, should settle for a well-informed estimate of the limits of your potential, with a generous margin of safety. It sounds like your health is giving you a lot of hints about where the margin of safety might lie.
Pace yourself. It's a marathon, not a sprint.