Getting old. Neck pain. Run down. Got a physical last week. Doing some followup blood work next week.
These late nights used to be effective. If I stayed up till 3:00am and you stayed up till midnight, we could get a lot done. Nowadays, if I don't get to bed by ten, I'm dragging tomorrow. I can get away with that when the market is slow and I don't have anything scheduled for the morning... kind of.
I tried exercising. It took two days to recover. Perhaps I should follow your lead and get a bike.