I didn’t say it was old age: I was probably ready for retirement when I was 30 🙂

But yeah, some folks seem to be more “tuned” to be active during certain hours than other folks. My ideal balance seems to wake up at around 8:00 am, work from about 10:00 am until about 2:00 pm, sleep until 5:00 pm, then work again from about 7:00 pm until about midnight. Waking up at 6:00 am and working from 8:00 until 5:00 pm in one stretch doesn’t work so well for me. This is compounded by the fact that I don’t do a good job “breaking up” the day- I should probably go for a 15 minute walk or something at some point during the day.

I also find that meetings, at least meetings that are “serious”, are a bit like running a marathon. Longer ones can have an effect that lasts right through until the next day.