Anything good for your brain + body when not grinding is also probably your best bet for optimal grinding. That’s going to be a combo of diet, vitamins, supplements, and yes... exercise
One strategy I have not seen widely discussed in poker is the use of aromatherapy via essential oils. Specifically, oils with high concentrations of sesquiterpenes that raise oxygen levels in the brain. Conversely, different blends of essential oils have compounds that can help counter anxiety & other issues.
Most “drugs” will provide short term benefits with more significant long term consequences. Specifically if not otherwise necessary and used predominantly for grinding
Benzo’s: Act as a tranquilizer on the brain. The amygdala is mainly responsible for anxiety, the prefrontal cortex for complex thought & planning, various parts of the brain for memory. In a perfect world benzo’s would only act on the amygdala. In reality they act on & slow down activity in your entire brain. Highly addictive (physical dependence begins to develop after ~2days of use, withdrawal symptoms are significant and lengthy). Also decreases impulse control which could be destructive in a poker setting.
Stimulants: long term use for “grinding” = overworking your brain without enough rest leading to eventual decrease in executive functioning
Most of the positive effects felt via caffeine intake by regular users are simply a response/end to symptoms of caffeine withdrawal. Short term use improves brain function/memory/alertness for a short time. Non-regular caffeine users who will experience increased mental alertness will also experience negative side effects more severely like anxiety. After it has worn off you will start to crash and need to rest or reup on caffeine. Long term compared to no caffeine intake it acts as a placebo at best. Haven’t seen any evidence that it improves functioning over an extended time period (& there have been a ton of studies attempting to prove this), I would expect the opposite to happen in a “grinding” setting. Caffeine derived from plants vs. synthetically produced caffeine will lead to better results. Here is a good article about it that relates to stimulants as a whole
https://www.trueprotein.com.au/natur...hetic-caffeine