Now limbered up, they suddenly form a loose circle and begin clapping and chanting before they resume a group stretch.
This is laughter yoga, a sidesplitting new fitness fad that's part traditional yoga, part improv and all silliness.
About 60 U.S. instructors who trained in India with the man who invented the style now instruct thousands of practitioners from California to Connecticut. About one-third of the known American laughter yoga clubs are in California, said Sebastien Gendry, founder of the American School of Laughter Yoga in Pasadena.
Jeffrey Briar, who founded the Laughter Yoga Institute in Laguna Beach a month ago, said his daily yoga lessons are now such a common sight on the beach that dog-walkers and joggers no longer stare. Sometimes they even join in.
Briar has practiced laughter yoga for more than a year and said he has shared his discovery with more than 4,500 people at the daily beachside sessions. It doesn't matter the laughter is forced or fake in the beginning, he said.
"Most people think they have to feel good first in order to laugh. But you can start from nothing; you can even start feeling unhappy and just laugh as a form of exercise, and happy feelings follow," said Briar, a slight 51-year-old with a perpetual grin, intentionally mismatched Converse sneakers and piercing blue eyes.
Briar, who also teaches more traditional yoga, said laughter enhances the breathing exercises that are so important to yoga and creates social interaction that isn't found in other styles that focus more on inward concentration.
"If you're laughing with a group of other people, fake laughter very quickly becomes real," he said. "It's part of the social phenomenon."
Numerous scientific studies have found that daily laughter can help lift depression, lower blood pressure and boost the immune system, but yoga and health experts say little has been done to study the combined effects of chuckles and chakras.
Roger Cole, a San Diego-based certified yoga instructor and Ph.D. in health psychology, said laughter yoga builds on the idea that certain poses can combat depression. But he worries about the forced nature of laughter yoga.
"The idea that putting a posture, as it were, on your face - a smile - is an idea that's not foreign to yoga," Cole said. "But the whole concept seems pretty contrived and uncomfortable. I think it could work, but there are more tried and true versions out there."
Back at the beach, Briar's daily class looks a lot like a scene from "One Flew Over the Cuckoo's Nest."
Some are bundled in jackets and scarves against the winter chill, and they begin by warming up with trills and chirps as they stretch their arms overhead and rotate their hips.
Then it's on to the really serious stuff: a 45-minute series of light yoga poses interspersed with improv-style exercises that include telling an imaginary joke in gibberish, opening a phantom "milkshake of happiness," playing on an imaginary swing set and scurrying around the beach while flapping and squealing like a seagull.
The class ends with members lying on their backs on the sand, murmuring in gibberish, chuckling spontaneously and beating their chests and stomachs. Briar's only rule is they can't use any real words - only nonsense - as they wind down.
Mercedes Cedillo, 45, attended her first laughter yoga class with a friend this week. At first she was self-conscious as Briar led the group through childish pantomimes, but that all changed by cool-down time.
"At the beginning I was like, 'Oh my God. What am I doing? This is very silly,' " said Cedillo. "But then you get connected to the inner child and the things that we normally would get stressed about you can laugh at."
On the Web
Laughter Yoga Institute at Laguna Beach: www.joyfulb.com
Laughter Yoga International: www.laughteryoga.org
American School of Laughter Yoga: www.laughangeles.com