Large-brained types at Northwestern University performed a little research and concluded that the one fine way to guarantee yourself a good night's sleep is to have a purpose in life.
How, though, did they measure it? Well, participants were asked to rate their response to such statements as, "I feel good when I think of what I've done in the past and what I hope to do in the future."
Link:
https://www.inc.com/chris-matyszczyk/science-just-declared-this-is-the-secret-to-a-good.html