Boulder, Colorado is the number one happiest city, according to the National Geographic Gallup Special/Blue Zones Index. Thanks to its sense of community, access to nature, sustainable urban development and preservation policies, Boulderites overwhelmingly feel "active and productive every day," National Geographic noted from Buettner's research.
"Per capita, more people walk to work in Boulder than in any other city in the U.S. Low rates of smoking and obesity, and high rates of exercise, contribute to the satisfaction locals feel," according to the publication.
Happiness may arguably seem immeasurable and Buettner admits that academically speaking, it's a meaningless term.
But tied together with statistics, Buettner says you can measure life satisfaction by:
- asking people to rate their lives as a whole on a 1-10 scale
- scoring their emotions by asking them how much they smiled, laughed or felt stress in the last 24 hours
- approximating their purpose by asking them if they get to "use their strengths doing what they do best every day."
Buettner says that if you want to become happy, you should change your environment, not your belief system.
"Your beliefs aren't going to change. But data now exists to show us how to optimize your surroundings so you're more likely to be happy," he says. "Living by water, in a bikable community and in a place with easy access to fruits and vegetables all stack the deck in favor of happiness."
Gallup senior scientist Dan Witters established 15 measurable expressions of happiness and together with the researchers used them to determine how strongly these resonated with the interviewees.
In his book, Buettner wrote about three "strands" of happiness that were key to formulating the list of happiest cities: pleasure, purpose and pride.
Pleasure is enjoying life in the moment while purpose is about living out your values and passions while serving a greater purpose, he explains. He adds that pride is about how satisfied people feel with their accomplishments in life.
"The formula for solid, long-lasting well-being weaves all three strands of happiness together," Buettner wrote in his book.
Buettner's offers this advice to millennials who may feel unhappy living or working where they do: "As long as you make enough for food, shelter, healthcare and some mobility, you should only do a job you love and uses your skills/passions," he says. "You will be much happier in the long run."
"Also it helps to move to a bikable community and ditch your car," Buettner adds.
Like this story? Like CNBC Make It on Facebook.
Stanford psychologist says this mindset shift will make you happier and more successful
4 questions to ask yourself to figure out what you really want in life