Endorphins are a category of neurotransmitters that the body uses as an internal pain killer. These compounds are also responsible for the all-encompassing sense of happiness we sometimes feel. Endorphins are thought to reduce blood pressure and have been linked in the fight against cancer. People who exercise know endorphins well, as they produce what is known as 'runner's high'. These same pleasant feelings are also experienced by people who meditate, and studies show this is due to the higher levels endorphins that meditation elicits.