the Israeli chemist, Raphael Mechoulam has shown that people can naturally form their own “bliss molecule.” This chemical is called anandamide and it stimulates the nervous system much as smoking marijuana does.
When the body releases this substance, it produces a sense of absolute pleasure without any adverse side effects. To trigger its production, you need only exercise or experience states of ease and flow while doing work.
But yogis can take it a step further. By learning to control their bodies to an incredible extent, they can produce anandamide simply through concentration and willpower.