I've been trying to sleep less, ideally between 4 and 7 hours a night. It's amazing when you get 20 hours in a day - it's almost like two distinctively different days. I feel twice as alive as when sleeping 8, 10, or 12 hours.
I'm still adjusting to it, though. Often I'm slower immediately upon waking up, which is not great, but not terrible. The way I start my day is by stretching and going for a walk or otherwise exercising, then eating some simple food, and having a shower. That first hour or two comes pretty automatically.
But then, I find my energy waxes and wanes more when on lower sleep. I actually feel more alert during my peak moments when sleeping less, but then I hit a low patch of exhaustion for 20 minutes to an hour every so often. During this time, my mind is mostly empty and scrambled.
The danger is that it's easy to get into some mindless clicking around at that point, and get stuck in click-click-click-click online for the next few hours. Normally when my mind is foggy, I like to do really low level admin that doesn't require thought: Reply to routine emails, clean something, things like that. Right now, though, it was a little frustrating, because I have basically no low level tasks to be done. Inbox is pretty much empty, no errands to run, my things are generally clean and orderly. So I was starting to click-click-click mindlessly.
I mixed some instant coffee and went outside. I'm staying on top of Mount Davis on Hong Kong Island, and lightning was striking across the water on the Kowloon Peninsula. So I sat out there watching the lightning strike again and again.
Haruki Murakami, the excellent Japanese novelist, wrote about the sign inside his Japanese gym. It was something like,
"Fat is easy to get and hard to lose. Muscle is hard to get and easy to lose. Such is life."
It's similar to another Japanese expression about money --
"Getting money is like digging in sand with a needle, spending it is like water soaking into sand."
I remember where I read the first quote -- it was reading "What I Talk About When I Talk About Running" in 2008, when I was in Barcelona and living near Placa Espania. At the time, I happened to be on a fantastic routine of waking up at 4:30AM, reading and eating in a little Spanish shop that served a fantastic Spanish egg/potato/vegetable omlette until my gym opened, spending a couple hours in the gym, and then working until dinner before sleeping early.