- You don't complete your dissertation by pulling a few all nighters. Only incremental work will get it done. Not years of hard work (it will kill you), but years of a couple (a few) hours a day
- You don't ruin your health overnight. It takes months of do a significant damage to your health. And it doesn't have to be months of heavy drinking or drug abuse. Just months of, let's say, bad sleeping habits.
- You don't get your health back overnight. It takes months of work to get it back. Again, I'm not talking about months of hard work, just months of doing little things right.
- You don't land a job by sending out a few resumes. It takes months of consistent search to find a job.
But a PhD program is a marathon. Sprinters always lose in a PhD program. You shouldn't try to spring with anything in a PhD program (e.g. comprehensive exams, dissertation). Those things are done incrementally. Again, not by working intensively, but by working consistently.