Belly Laugh Day

What the day is

Global Belly Laugh Day is observed on January 24. It encourages people to have a good, deep laugh, the kind that shakes the stomach, and to spend the day with people who bring it out. The day is informal, and the exact origin is not well documented.

Its timing helps. Late January is among the grayest stretches of the year in the northern hemisphere, and a laugh is a quick way to lift the mood.

Origin and background

Laughter is among the oldest human behaviors. It appears in infants within a few months of birth, long before speech, and it has close relatives in the play sounds of other primates. Researchers who study it, including the evolutionary psychologist Robin Dunbar, have found that laughing together in a group raises pain tolerance, probably because it releases endorphins, and helps people bond.

The physical effects are well documented even if the long-term claims are sometimes overstated. A real laugh uses the muscles of the face, chest and abdomen, increases heart rate briefly and lowers levels of the stress hormone cortisol afterward. Most studies find a short-term benefit to mood and stress. Evidence that laughter prevents illness in the long run is weaker, and it should not replace medical care.

The idea has also spawned a movement. Laughter yoga, started in India in the mid-1990s by a physician, Dr. Madan Kataria, uses forced laughter in groups, which often turns into the real thing, and clubs around the world meet to practice it.

How to take part

• Watch or listen to something you find truly funny, such as a favorite comedy, a stand-up special or old home videos.
• Call a friend who makes you laugh and share a story you both find ridiculous.
• Try a few minutes of laughter yoga, starting with a deliberate laugh and letting it become natural.
• Play a game that draws out silliness, such as charades or a round of bad jokes.
• Look for the humor in a small annoyance today and laugh about it, rather than complain.