(CNN) If you could wish for just one thing, would it be happiness or a long life? Given what researchers tell us, one is likely to produce the other.
Science has been exploring the connection between happiness and longevity for some time. A 2011 analysis of nearly 4,000 Brits found those who said they felt content, happy or excited on a typical day were up to 35% less likely to die prematurely. In a 2016 study, a positive outlook was associated with longer life for nearly 4,000 older French men and women studied over 22 years.
Researchers followed more than 2,000 Mexican-Americans in 2015 and found those who were more positive in their world view were half as likely to die. And a 2011 study followed around 200 women and men from San Francisco over 13 years and found those who reported more positive than negative experiences also lived longer.
According to research on the Positive Psychology Center website, striving for well-being will allow you to perform better at work, have better relationships, a stronger immune system, fewer sleep problems, lower levels of burnout, better physical health and -- you'll live longer.
Great! But how do you obtain happiness? That's the tough question, especially since the meaning of the word isn't even scientifically agreed upon.
"Happiness comes in different sizes and flavors," said cardiologist Dr. Alan Rozanski, a professor of medicine at the Icahn School of Medicine at Mount Sinai who studies optimism.
"There is the transient type, fed by such things as a walk in a park, spending time with a friend, or eating that ice cream you love," he continued. "But these feelings of happiness come and go."
What creates a sustained feeling of happiness, say experts, is a mixture of traits like optimism and resilience, fed by behaviors such as expressing gratitude, forgiveness and being kind to others, all held together by a strong sense of purpose.
Add to that mix one master ingredient: a sense of community characterized by warm, supportive, satisfying relationships with others.
Now that we have something of a working recipe for happiness, let's find the ingredients.
"People who are more socially connected to family, to friends, to community, are happier, they're physically healthier, and they live longer than people who are less well connected," said Harvard psychiatrist Robert Waldinger in his popular TEDx talk. "And the experience of loneliness turns out to be toxic."
Waldinger is the fourth director of the Harvard Study of Adult Development, which followed the lives of 724 Boston men for more than 75 years and then began following more than 2,000 of their offspring and their wives.
Among the original recruits in the study were President John F. Kennedy and longtime Washington Post editor Ben Bradlee.
The unprecedented study has allowed researchers to get closer to determining the main characteristics of a happy life.
"The lessons aren't about wealth or fame or working harder and harder," Waldinger said. "The clearest message that we get from this 75-year study is this: Good relationships keep us happier and healthier. Period."
You don't have to have dozens of friends or even be in a committed relationship, he stresses.
"It's the quality of your close relationships that matters," Waldinger said. "High-conflict marriages, for example, without much affection, turn out to be very bad for our health, perhaps worse than getting divorced. And living in the midst of good, warm relationships is protective."
Optimism and pessimism are the yin and yang of happiness. Optimists are people who expect good things to happen to them, while pessimists expect bad things to happen.
It turns out that looking on the bright side of life is really good for your health. Research has found a direct link between optimism and a stronger immune system, better lung function and cardiac health.
A recent meta-analysis of studies found that compared to pessimists, an optimist had about a 35% lower risk of major heart complications, such as a cardiac death, stroke or a heart attack.
"In fact, the more positive the person, the greater the protection from heart attacks, stroke and any cause of death," said Mt. Sinai's Rozanski, who was the lead author on the study.
There are a lot of reasons why a positive outlook might improve your physical health and help you live longer. It reduces the stress hormone cortisol, which controls inflammation, blood sugar and blood pressure levels, all key factors in disease development.
Optimists also have better health habits. They're more likely to exercise, have better diets and are less likely to smoke.
"Optimists also tend to have better coping skills and are better problem-solvers," Rozanski said. "They are better at what we call proactive coping, or anticipating problems and then proactively taking steps to fix them."
Whatever the reasons, a 2019 study of nearly 6,000 people from Harvard's Health and Retirement study found optimists had a 24% increased likelihood of maintaining healthy aging.
A sense of purpose and meaning in your life is a big part of living a longer, happier life, according to psychology professor Lyle Ungar, who has developed what he calls the Well-Being Map. It rates every US county on such psychological factors as openness, trust, agreeableness and neuroticism.
"Do you have a job or a calling that makes some sense?" Ungar asked in an interview with CNN last year. "The way to happiness is not by choosing to be happy, it's to find meaning in life. Go volunteer, spend time at a charity, give something of yourself. The people who are doing fine in that way are living longer."
Lord Richard Layard, one of Britain's most prominent economists and the author of several books on happiness, also believes that to make ourselves happy we should focus on the well-being of others.
"A society cannot flourish without some sense of shared purpose," he writes in his landmark book, "Happiness: Lessons From a New Science."
"If your sole duty is to achieve the best for yourself, life becomes just too stressful, too lonely -- you are set up to fail. Instead, you need to feel you exist for something larger, and that very thought takes off some of the pressure."
Studies by the Pew Research Center show that actively religious people are more likely than less- or non-religious people to describe themselves as "very happy." They also share some traits that could improve their chance at a longer, happy life: They are less likely to smoke and drink, and more likely to join clubs and volunteer at charities.
"I'm surprised how good religion is for people," Ungar said. "Religious people are more agreeable, they're happier, they live longer."
It doesn't have to be a traditional religion. Layard points out that spiritual practices ranging from meditation to positive psychology to cognitive therapy can also feed an inner life.
University of Pennsylvania psychologist Martin Seligman, who co-founded the field of positive psychology, has developed a theory he believes will enable well-being, which some experts argue is a better goal than happiness.
Seligman has developed five building blocks toward well-being he calls "PERMA." Each of them stand independently of the others, and should be pursued for "its own sake, not as a means to an end."
"P" stands for positive emotion, which you can cultivate in hope for the future and an appreciation for the past. By practicing gratitude for what you've been given and forgiveness for what you were not, Seligman feels you can create positive emotion about your past. Build hope and optimism, he says, and you build positive emotions about your future.
"E" is for engagement, which he defines as fully using all your skills, strengths and attention on a challenging task. Doing this, he says, will put you in the "flow," sort of a mental version of the athlete's "zone."
"R" is for relationships and the critical importance they have in our lives in amplifying both our positive and negative feelings.
"M" is for meaning, a sense of purpose from being part of something bigger than ourselves. He points to religion, family and social causes such as working for a better environment as ways to increase meaning in our lives. Research shows doing acts of kindness for others can also increase our well-being.
And finally, "A" is for accomplishment. This is not necessarily financial success, but success and mastery of a skill or activity for its own sake.
Or as the Dalai Lama has said: "Happiness is not something ready-made. It comes from your own actions."