Yes, being happy feels good. But a new review of existing research adds more weight to the idea that being happy could actually improve our physical health, helping in areas ranging from faster wound-healing to adding a few years to your lifespan, according to a TIME piece on the findings.

The new review, published in the journal Applied Psychology: Health and Well-Being, looked at more than 150 individual studies and more than 20 existing research reviews to examine how people’s own evaluation of their lives (called subjective well-being) impacted their physical health, Amanda MacMillan wrote for TIME.

The findings look good for happy folks: the review leaves “almost no doubt” about the positive influence of happiness on health, lead author Edward Diener, PhD, a professor of social psychology at the University of Utah, told TIME, though the how and why are a bit complicated.

The review suggest that happiness can have “beneficial effects on the cardiovascular and immune systems, influence hormones and inflammation levels and speed wound healing,” MacMillan wrote. Plus, happiness has also been tied to longer telomeres—shoelace-like caps that sit at the end of our chromosomes and shrink as we get older—which points to a connection between psychological well-being and “aging and health at the cellular level,” the study authors told TIME.

There are a few reasons why happiness could have such profound effects on well-being. One might be that happy people are more likely to do good things for their mental and physical health, like making sure to sleep enough, exercise and eat well. Additionally, since many of the studies relied on observation, it could be that variables that weren’t measured or reported on were responsible for changes in health and happiness.

“Being happy certainly isn’t a guarantee that you’re going to be healthy, and it’s true that some studies haven’t found an effect,” Diener told TIME. But the review gathered enough evidence for doctors—and the general public—to take happiness seriously. Diener told TIME that, hopefully, these findings could help inform how doctors treat patients—a future where “happiness levels” may be a box you fill out on your intake form at the doctor’s office.

“People are doing a lot of things to stay healthy; they’re jogging, riding their bikes, eating fruits and vegetables,” Diener told TIME. “We want to remind people that there’s one more thing you need to work on that can also have a big effect on your physical and emotional well being.”

But real happiness, according to Diener, isn’t just about jogging and drinking green juice: it extends to your daily life as well. “Learning to enjoy your work, being more grateful and having really positive relationships are important too,” he told TIME.

Read more on TIME.