Throughout my career, I've experienced one consistent problem. There are days when I sit down to play poker where I feel that I am completely enveloped in a mental fog. The sensation is very similar to waking up in the middle of the night or being up for 36 hours straight, but happens after a full night of sleep. I exercise like a fiend (yoga, rock climbing, weights) and have a pretty healthy diet that is low in carbs. I do struggle with sleep, but find that reading an actual book (not on a laptop or kindle) is helpful and since I play poker professionally, waking up at 4 am and reading for an hour and waking up later isn't really a problem.
I would estimate that my winrate drops 3-5 bb/100 when I'm in this groggy state as I lose access to much of my higher level poker thought process and can't evaluate ranges to the extent that I am capable. I tend to play earlier in the day since this grogginess gets worse in the afternoon/evenings. I have a lap that is designed to help with S.A.D. and which seems to help sometimes, but not always.
Things I'm going to try:
Absolutely no screen time 1 hour before bed. I use f.lux, but I'm going to go for the nuclear option. No more falling asleep to Phil Galfond videos, regardless of how relaxing they are
Start the morning with meditation. I've never been able to stick to this habit, but I'm going to make an effort to do so
Add more cardio. Even 10-15 minutes of running might be helpful.
Let me know if any of you guys have experienced something similiar, I would love to hear your feedback and discuss solutions.