Originally Posted by detourglr
also to... make sure a bathroom is nearby... and snacks and drinks too.
I would advise differently. If you are having trouble concentrating then break up your session with short breaks. only go to eat and pee during those breaks.
every 2 hours take a short rest. take a walk, make a snack or lunch (not junk food, go for protein snacks, chicken/tuna salad etc and water) do some light exercise and take your mind off poker for 15-30 mins or so. then when you return to your poker office your mind will be sharper and able to focus more.
Of course, if you weren't having concentration problems then detourglr is right, cos you wouldn't want to be breaking your flow to go get food.
in your case i think you would benefit from multiple short, intense sessions rather than 1 longer one.