Absolutely. And in ways that aren't super obvious.
If I'm annoyed with someone or something, I get worse results at the tables. If I'm hungry, tired, or rushed, same thing. I used to "fit a few
hands of poker in" if I have 20 minutes to kill. I don't do that anymore.
One of the biggest things for me mentally/physically that I've adjusted that I find incredibly helpful, I don't play any poker now until the following three conditions have been met.
1) All my big responsibilities/jobs for the day have been taken care of
2) I've been outside, even if just for a few minutes
3) I've done my stretches. I have a 20 minute stretching routine that I do every day. (I picked up this habit years ago in physio-therapy by a therapist who took inspiration from yoga)
Those three things combined with staying hydrated and not playing frustrated or tired are vital for my mental game.