You've probably heard time and time again that age is just a number—and you may or may not believe it. But if the scientifc proof behind "old-man strength" isn't enough to convince you that it is possible to feel younger as you get older—with some help from a diet of anti-aging superfoods and a high-intensity interval training regimen, of course—then this new research might just be enough to change your mindset.

People who feel closer to their actual age are less likely to be satisfied with their sex life, according to a recent study from the University of Waterloo published in The Journal of Sex Research

So those who act and feel more youthful—even if they're actually 65—are more likely to report a higher-quality sex life and being more interested in having sex in general. 

In the study, researchers examined the attitudes toward sex and aging of a group of over 1,100 adults from their mid-40s to their mid-70s over the course of a 10-year period. "For people in mid- to later-life," said Steven Mock, an associate professor in Recreation and Leisure Studies at Waterloo, "feeling young at heart actually appears to make a difference in the bedroom."

But even if you don't feel young at heart just yet (here are 14 great ways to start supercharging your vitality and energy), that doesn't mean you can't spice things up in the bedroom—check out 8 ways to have amazing sex in your 40s and these 52 foods that boost penis health, supercharge libido, and increase pleasure