Here's some incredibly good news, especially if you're the kind of person who wants to sleep better and live longer -- maybe even many years longer.

(Honestly, who doesn't fit into at least one of those two categories?)   

Let's start with living longer. An enormous study recently combined two research projects that examined data on a total of 71,173 people, some of them over 30 years, and found that having an optimistic outlook on life was associated with living significantly longer.

How much longer? As much as 15 percent, which could easily translate to 10 years or more.

The researchers, from several institutions including Harvard, drew on data from the Nurses' Health Study (NHS) the Veterans Affairs Normative Aging Study (NAS).

They found that maintaining an optimistic outlook was associated with greater longevity than their less-optimistic peers,regardless of other factors that we associate with longer life, such as:

  • making healthy choices (or lack thereof),
  • socioeconomic status,
  • health conditions,
  • incidence of depression, and
  • "social integration."

"Our results further suggest that optimism is specifically related to 11 to 15 percent longer life span, on average, and to greater odds of achieving 'exceptional longevity,' that is, living to the age of 85 or beyond," the study's authors wrote.

All of that is pretty darn good news, especially if you can train yourself to be the kind of person who instinctively looks on the bright side.

But wait, there's still more.

Separately, a five-year study of 3,500 people living in three different U.S. cities found that optimistic people fall asleep faster, sleep better and longer, and are generally better rested than their less-optimistic peers.

Longer life and better sleep, what's not to like?

While the causal relationship between optimism and sleep isn't determined by the study, one theory is that the behaviors that ultimately make people more optimistic also can lead to more restful sleep (as opposed to the idea that optimism itself leads to better sleep).

"Optimists are more likely to engage in active problem-focused coping and to interpret stressful events in more positive ways, reducing worry and ruminative thoughts when they're falling asleep and throughout their sleep cycle," said the study's author, Rosalba Hernandez, a professor of social work at the University of Illinois.

Either way: Sleep better, and live longer, and it's all associated with simply having a more optimistic outlook on life. Even if it's all a self-fulfilling prophesy, it's one worth trying to adopt.