Taking an overly positive view of the world can obviously be a detriment, as anyone who's left an umbrella at home can tell you. That said, a little bit of optimism can go a long way, allowing yourself to see the brighter side of certain situations and push through crises and stress.

Well, chalk one up for the optimistic thinkers: Having a positive perception of your activity levels and fitness can help you beat a premature death, according to a new study from Stanford University.

Researchers checked out the responses of more than 60,000 adults in the U.S. who had responded to surveys that noted their physical activity levels. The researchers honed in on one specific question: “Would you say that you are physically more active, less active, or about as active as other persons your age?" They then checked the death records for 21 years after the first survey, which was done in 1990.

The results: When controlled for actual physical activity and stats like age, weight, and illnesses, people who thought they were less active ended up being 71% more likely to have perished in the years before this new study.

"Placebo effects are very robust in medicine. It is only logical to expect that they would play a role in shaping the benefits of behavioral health as well," said Alia Crum, Ph.D., assistant professor of psychology at Stanford. "Our findings fall in line with a growing body of research suggesting that our mindsets—in this case, beliefs about how much exercise we are getting relative to others—can play a crucial role in our health.”

Of course, don't bank on living longer just because you feel like you're a decently in-shape dude—it pays to hit the gym pretty often, too. Here are five ways to motivate yourself to get off the couch and into the weight room.