What is it that singles out these miraculous die-hards from the rest of us?

Did you know that laughter can balance body chemistry, and even help to alleviate pain? In fact, there is a whole raft of positive effects it has on our physiology, from improving our immune responses, to decreasing the risks of heart disease. With no side-effects and a free price tag, it's not hard to see why researchers are keen to nail down the mechanics behind this most complex of human traits. Everyone can laugh. It brings communities together and strengthens familial an