Not getting enough sleep impacts your ability to focus. It makes it harder to stay on task and come up with new ideas. It also affects your ability to make decisions. Like, you know when there’s something that you need to do, but you keep deciding to watch Netflix instead? Getting enough sleep can help with that.
If you get enough sleep, your work will be better, your focus will be better, and you’ll have more willpower. All of this stuff leads to better self-discipline.
I’ve seen this in myself as well. Whenever I don’t get enough sleep, my entire day goes to shit. I get lazy. I can’t stay focused on anything I’m doing. Instead of doing all the things that I had planned to do, it becomes much easier to sit around on reddit all day. If I manage to do something productive, it’s usually half-assed, and I hate doing it.
On the days where I do get enough sleep, it’s so much easier to get shit done. I’m focused, I feel energized, and I’m excited about all of the things that are coming to me as a result of my work, so I want to work toward my goals.
Trying to get disciplined while sleep deprived (and no, caffeine isn’t an acceptable substitute) is like playing life on hard mode. Get a full 7-8 hours each night, and it becomes so much easier to get started and stay focused on your work.