Had one of my famous Fridays where I fall asleep at 7pm, exhausted. This has not happened as much as it did when I was a traveling salesman, but it still happens. I also tore something in my back while sneezing and cannot sit up or stand straight.
I notice that I can lie to myself and keep my brain working indefinitely. Usually I sound like a psycho and scare everyone around me, but the quality of work done never suffers. When my body starts to fall apart, then I worry. I start to think that I should not be doing this to myself.