It seems that the more candles you blow out on your cake, the happier your life can be. It's known as the paradox of aging — so many things supposedly worsen with age, yet older people often have a better sense of overall well-being.

Researchers continue to find explanations for the reasoning behind why happiness seems to increase with age. In the latest study, researchers surveyed more than 1,500 San Diego residents between the ages of 21 and 99, and found that those in their 20s were the most stressed out and depressed, while those in their 90s were the most content.

“The consistency was really striking,” Dilip Jeste, director of the UC San Diego Center for Healthy Aging and senior author of the study, told the Los Angeles Times. “People who were in older life were happier, more satisfied, less depressed, had less anxiety and less perceived stress than younger respondents.”

The study was published in The Journal of Clinical Psychiatry.

The authors suggest that some of that improved sense of well-being could come from the wisdom people collect as they age. Jeste defines wisdom to include empathy, compassion, self-knowledge, openness to new ideas, decisiveness, emotional regulation and doing things for others rather than just for yourself.

“As we get older, we make better social decisions because we are more experienced, and that’s where wisdom comes into play,” he told the Times.

The study — and the resulting explanation — is just one of many in recent science literature explaining the link between aging and well-being. Here's a look at several other reasons we might be happier as we get older.

We become more trusting

Two large-scale studies by researchers at Northwestern University and the University at Buffalo found that as people get older, they also get more trusting. And that trust can benefit their well-being.

"Our new findings show that trust increases as people get older and, moreover, that people who trust more are also more likely to experience increases in happiness over time.” Claudia Haase, a professor of social policy at Northwestern and one of the study's authors, said in a statement.

In the first study, the researchers looked at the association between trust and age in nearly 200,000 people from 83 countries over the past 30 years. The second study followed 1,230 people of different ages in the U.S. They were Millennials, Generation X and Baby Boomers.

Both studies found that people became more trusting as they aged, and that increased trust led to more happiness and well-being.

The studies, combined into one research paper, were published in the journal Social Psychological and Personality Science.

“We know that older people are more likely to look at the bright side of things,” Haase said. “As we age, we may be more likely to see the best in other people and forgive the little letdowns that got us so wary when we were younger.”

senior couple buying produce Older people typically eat more produce than younger people, which can contribute to better well-being. (Photo: wavebreakmedia/Shutterstock)

Our bodies and wallets are healthier

People over 55 have an overall better sense of well-being for all sorts of reasons, according to a 2015 Gallup-Healthways survey of 173,656 people across the U.S.

They have higher rates of financial well-being, where 52 percent of people over 55 reported they were thriving, compared to 32 percent of Americans younger than 55. They have better access to health care, compared to those under 55. They also smoke less and eat more fresh produce than their younger counterparts. Levels of depression and obesity also drop off after age 64.

"Older Americans express more satisfaction with their standard of living, worry less about money, and say they have enough money to do what they want to do — all at higher rates than their younger counterparts," the report says.

Blame the brain

As people get older, they tend to let go of negative emotions and situations and focus on positive events, some psychologists believe. Researchers at Northeastern University and the Georgia Institute of Technology found that when they showed older people pictures of faces or situation, they focused on and remembered the happier ones more and the negative ones less.

Cognitive processes, some researchers believe, help older people regulate their emotions, "letting them view life in a sunnier light."

The researchers' work is published in the journal Perspectives on Psychological Science.

Small things matter

When you're younger, you often look for extraordinary things to give you pleasure. That's when you're falling in love, maybe starting a family, traveling and doing lots of exciting things. Researchers from Brown University found that while younger people tend to seek out these more memorable adventures, older people are happy with ordinary, everyday things.

“It’s just what you would expect, this emphasis on savoring what you already have when your time starts to become limited,” Peter Caprariello, assistant professor of marketing at Stony Brook University, told the New York Times.

So a cup of coffee with friends or a walk with the dog makes you happy; there's no need to wait until the next exotic vacation or gourmet dinner.

The researchers write in the Journal of Consumer Research: "As people move through their lives deciding how to fill their next hour, weekend, or vacation, they are frequently reminded by proverbs and popular culture to spend their time wisely because their days are numbered."

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.