Chau looked online for ways to feel better. When laughter yoga showed up in her search results, she was intrigued and signed up to try it. Unknowingly, instead of a regular class, she had enrolled in a two-day instructor course.

She only discovered the mistake five minutes into the course, but as she had already paid for it, the stay-at-home Hong Kong mum chose to continue.

The first few hours of the course were “strange”.

“We were like children, playing and acting silly. We also had to pretend to laugh, which felt weird.”

Slowly, she was able to let herself go – and that’s when she realised that she might be on to something.

“My smile went from fake to genuine, my laughter went from deliberate to involuntary, and the tension in my body melted away,” she says.

The next day, she left the course a qualified laughter yoga instructor – feeling happier and more relaxed than she had been in a while.

Laughter yoga is an aerobic exercise introduced in 1995 by Indian doctor Madan Kataria. Its concept is based on scientific studies that prove that the body cannot differentiate between voluntary laughter and real laughter, and that we get the same physiological and psychological benefits from both.

“There are no jokes, humour or comedy involved in laughter yoga,” says Alex Lo, the CEO and founder of the Hong Kong Laughter Yoga Academy. “Instead, we combine voluntary laughter and playful movement with breathing exercises.”

The breathing exercises improve blood circulation and increase oxygen delivery to the body’s cells, Lo says, adding that laughter yoga can lift one’s mood in minutes, reduce stress and strengthen the immune system.

According to Michael Titze, a German psychologist and pioneer of humour therapy, intensive laughter strongly stimulates breathing, floods the skin on the head and face with blood, dilates the blood vessels and activates the tear ducts.

The heart is also stimulated as if doing strenuous physical activity, such as jogging or rowing. At the same time, the lungs are supplied with oxygen-rich blood, the digestive glands are stimulated and the diaphragm is activated so strongly that it literally jumps.

“This corresponds to an intensive massage of our internal organs, which is why we sometimes have to bend over with laughter,” Titze adds.

When we laugh, hormones called endorphins are produced in the brain that block the perception of pain and increase feelings of well-being. A state of relaxation sets in, causing blood pressure to gradually fall below its standard value, the heartbeat to slow and the muscles to loosen.

Hearty, extensive laughing has also been found to help the immune system, Titze says. For instance, the number of cells that protect against cancer and cardiovascular diseases increases; the activity and quantity of natural killer cells rise; antibodies that inhibit germs in the respiratory tract proliferate; and a higher level of an immune-modulating agent known as cytokine interferon-gamma is increasingly detectable in the blood.

Laughter also has the power to protect us from the destructive effects of negative emotions such as anxiety, anger or depression. This is because laughter brings about a change in perspective that lets us take things less seriously, says Titze, who has written several books about humour and health.

“A mentally healthy child lives a life that is far more cheerful than that of an adult,” he adds. “A statistical survey determined that preschool children laugh up to 400 times a day – at least 10 times more than adults.

“The explanation is obvious: a child’s life mirrors a playful attitude that is little influenced by those normative obligations that determine an adult’s life.”

Laughter, especially if it is extensive and intense, may help relieve this stress reaction.

Studies support the idea that laughter may reduce our risk of, or improve, certain illnesses. For instance, research by the University of Maryland Medical Centre in the US found that laughing for about 15 minutes a day can reduce the chance of suffering a heart attack.

Laughter appears to cause the inner cellular lining of the blood vessels – known as the endothelium – to expand to increase blood flow.

Authentic laughter has the most impact, meaning that it happens spontaneously and then takes its own way that does not follow any rules, Titze says.

“Authentic laughter is triggered by an involuntary reflex and arises in the belly. This kind of laughter is usually long-lasting.”

How do we laugh more, and more heartily? Watching a comedy and getting together with people that make us laugh are good ways to start. Titze says that once emotional well-being sets in, an authentic laugh may not be long in coming.

He adds that laughter yoga is also effective as it allows you to be loud and boisterous and to laugh without restraint.

Titze explains that authentic laughter can be triggered by one of three different “potentials” or components of a person’s neural network.

First is the motor potential, which includes breathing capacities and the activity of the vocal cords. Second is the emotional potential, which relates to feelings of exhilaration and amusement. Third is the cognitive potential, which relates to the recognition of comical or funny phenomena.

As soon as one of these components is triggered for a certain period of time, it affects the other components of the network as well, he says. “This is why a slapstick comedy not only elicits laughter but after a while also lifts the spirits.”

Chau, who is currently in remission, is thankful to have stumbled upon laughter yoga a year ago. She goes to sessions twice a month, as student or teacher.

Besides improving her own emotional well-being and changing her perspective on her health and future, she says that it has opened her eyes to her ability to help others feel good.

“It’s nice to have fun and laugh our hearts out, the way we did as children. Our lives are so busy and we are so caught up in our problems that we forget to have a hearty chuckle, but it’s important to let go of our cares every now and then and just be cheerful,” she says.

“Laughter is food for the soul.”