Laughter Yoga, also known as laughter therapy, has grown in popularity in Vietnam, creating a new club of fanatics who gather in the mornings everyday to chuckle and chortle their way to fitness.
Members of the "Laughter Yoga" group in the capital Hanoi wave their arms, clap and march for around 45 minutes.
The combination of unconditional laughter and yogic breathing is said to stretch muscles and trigger endorphins - the chemical in the brain known for its feel-good effect.
Participants prove there is truth in the old Vietnamese saying: "A good laugh is equal to 10 prescriptions of medicine."
Laughter yoga first started in India and the man who introduced it in Vietnam, Le Anh Son, claims it has the potential to change society.
"The biggest impact that it (laughter yoga) has on the society is it makes people more friendly, creates a friendly society where people have the habit if being friendly, to smile to each other," Sky News quoted him as saying.