I've noticed that, though I'm only working 40ish hour weeks, I'm exhausted. This has been going on for long enough that I've forgotten that it's not normal.
I'm careful with my willpower. I do, and track, only three mandatory things per day: I run (any distance), I meditate (any duration), and I take one photo. I've got logs of these, and it's very easy to see that when I'm getting exhausted at work, I don't do them, even if I have time. This is a problem, because it breaks the virtuous circle.
I'm proud of helping to create a strong company culture.. but, most times, when the team hits the pub I'm not there or I leave early. It's not because I'm working (although sometimes I am). It's because I'm tired.
Kathy Sierra says "even if you loved solving tough puzzles, the drain ... still happens". This is true, but it doesn't go far enough. Your cognitive resources want to be used. Mine are like pumped-up marines, eyeing every complexity with "you want a piece of me?", greeting every situation with "impossible odds, you say? Rock and roll!"
For a while I've been trying to throttle back - to pace myself by not fully committing. But that means doing things badly, and I don't do things badly. Energy and precision are what I care about. Just scaling back doesn't work.
So now I'm trying something else: refusing to engage at all. Anything I do, I do to the redline, as before. But, some of the time, I'm now flat-out refusing to get involved. Today I left a meeting just when a tricky operational issue came up, saying "Right, I'm throwing myself out.. because you guys got this".
This sacrifices some operational safety; the team is very capable, and I trust them, but there's always a chance that I know something, or have seen something, that they haven't.
It also sacrifices a rare and valuable training opportunity. It's always better to show people than to tell them.
And it sacrifices some behaviour, and connection, that I care about: It's very odd not to help someone when they're asking you to, you have the capability, and you're right there. It feels like a breach of trust.
But these sacrifices are absolutely necessary. As the MD your second-most-important function is to train, nurture and protect your team as they do their jobs. But your most important function is to do yours.