“Acting your age” may actually be hazardous to your health. A team of British researchers have found that the key factor in living longer lies not in any vitamin supplement, but rather in your own mind. It seems that those who feel younger actually live longer. Although the cause for this remains unclear, it does mean that, according to science, being immature is healthy.

Do you feel younger than what’s written on your birth certificate? Well you’re in luck because this might just add a few years onto your lifespan. In a recent research letter published online by JAMA Internal Medicine, scientists found that older people who felt three or more years younger than their chronological age had a lower death rate compared with those who felt their age or felt more than one year older than their actual age.

According to the press release, the team, from University College London, came to this conclusion by using data from a study on aging. A total of 6, 489 individuals were involved, and they shared an average age of 65.8 years and a self-perceived age of 56.8 years. The majority of the adults involved in the study reported feeling younger than their actual age, about a quarter of the participants felt close to their real age, and 4.8 percent reported feeling more than a year older than their chronological age.

The participants' actual lifespan greatly reflected their “self-perceived age.” Death rates during the average follow-up of 99 months were 14.3 percent in adults who felt younger, 18.5 percent in those who felt about their actual age, and 24.6 percent in those who felt older. The researchers commented that although this link was observed in cardiovascular death, it did not seem to exist in participants who had died from cancer.

“The mechanisms underlying these associations merit further investigation,” explained the researchers in the press release.

As the saying goes, age is just a state of mind, and this is not the first time scientists have observed mindset to affect a person’s health. Unhappy emotions, such as stress, grief, or sadness, release hormones that can be detrimental to your heart health.

“Your system is flooded with stress hormones, and if it happens often enough, those hormones can actually change the physiology of your heart," Dr. Mladen Golubic, medical director of a program focusing on heart disease reversal through stress management, told Prevention.

If you do feel older than you are, don’t despair. The team hopes that their study will open up intervention opportunities. They suggest that unhappy feelings associated with aging may be the root of this early death and suggest that “health messages promoting positive health behaviors and attitudes toward aging” may help to avoid it.

Source: Rippon S, Steptoe A. Feeling Old vs Being Old Associations Between Self-perceived Age and Mortality. JAMA Internal Medicine. 2014.