The key is found in recognizing the difference between stress and distress. Stress lets us know that we are working hard while distress is a signal that we are pushing beyond our ability to withstand increased work. When we ignore these warnings we fail to achieve our desired objective and end up taking steps backwards in our development.
Pushing through exhaustion helps us to see gains, but only if we are able to recognize when we are stretching into potentially injurious territory. We've got to be aware of the warning signs of injury if we want to maximize our maturity while minimizing risk.