"Older people are celebrated, they feel obligated to pass on their wisdom to younger generations," he says. This gives them a purpose in life outside of themselves, in service to their communities.

According to Buettner, the concept of ikigai is not exclusive to Okinawans: "there might not be a word for it but in all four blue zones such as Sardinia and Nicoya Peninsula, the same concept exists among people living long lives."

Buettner suggests making three lists: your values, things you like to do, and things you are good at. The cross section of the three lists is your ikigai.