I thought that's why most people drink coffee. I optimally sleep ~9 hours every day and start to feel tired if I sleep less for 3-4 consecutive days. I bike to

I thought that's why most people drink coffee. I optimally sleep ~9 hours every day and start to feel tired if I sleep less for 3-4 consecutive days. I bike to work (and generally tend to go as hard as I can, so heart rate tends to spend a lot of time in Z4 or so). I almost never drink coffee so it takes me 2-3 hours to "fully awake" but I don't think that's unnatural so I don't mind it, I let nature run its course.