Optimal brain functioning?

I play chess and condition my brain/body to maximize performance. It seems if I overdo the playing or the exercise, my overall processing speed temporally decreases, along with short term memory, but not always at the same time. I assume I need to stilt me activity so I can adequately recover, but if I do not, it seems the short term memory inefficiency may stay constant for longer periods. Is this likely the case/are there any better ways? thanks