how to mantain energy in 12 hours shift at work?

Cocaine.

Meth will maintain your energy.
Of course, you'll probably get hooked, lose your job (and teeth) and end up as a street hooker. But at least you'll have energy.

Coffee and a brisk walk outside to recharge

Be healthy and well rested going in.

2 2/5 five hour energy

oh god that sounds impossible :(