March 19

National Let’s Laugh Day

An annual observance on March 19 encouraging laughter and highlighting its documented physical and psychological health benefits.

Yearly Date

March 19

Observed in

United States

Introduction

National Let's Laugh Day celebrates a behavior with more science behind it than most people expect. In 1964, journalist Norman Cousins discovered that 10 minutes of genuine laughter gave him two hours of pain-free sleep while battling a degenerative spinal disease. His recovery, documented in the New England Journal of Medicine, helped launch an entire medical field.

That field, gelotology, has since confirmed what Cousins experienced. Laughter triggers endorphin release, lowers cortisol, boosts immune cell production, and provides measurable cardiovascular benefits. The holiday gives people a reason to take those findings personally.

National Let's Laugh Day History

The scientific study of laughter began with a psychiatrist who took humor seriously. In the 1960s, William F. Fry at Stanford University started measuring what happens inside the body during laughter. He documented changes in heart rate, respiratory patterns, and muscle tension, establishing gelotology, from the Greek word gelos (laughter), as a recognized field of research.

The field gained public attention through a journalist's illness. In 1964, Norman Cousins was diagnosed with ankylosing spondylitis, a painful degenerative disease of the connective tissue. Given a 1-in-500 chance of recovery, Cousins checked himself out of the hospital and into a hotel room, where he watched Marx Brothers films and Candid Camera episodes. He discovered that 10 minutes of genuine laughter produced two hours of pain-free sleep. His 1979 book, Anatomy of an Illness, became a bestseller and prompted UCLA to establish the Norman Cousins Center for Psychoneuroimmunology.

Laughter as clinical practice

In 1995, Dr. Madan Kataria, a physician in Mumbai, started a Laughter Yoga club with five people in a public park. The practice combines intentional laughter exercises with yogic breathing techniques. A core finding that made the practice viable: the body cannot distinguish between simulated and genuine laughter. Both produce the same endorphin release, cortisol reduction, and immune response. Laughter Yoga clubs now operate in over 100 countries.

National Let’s Laugh Day Timeline

1960s

William Fry pioneers gelotology

Psychiatrist William F. Fry at Stanford University began the first systematic study of laughter's physiological effects. His research established gelotology as a formal scientific field and documented how laughter affects heart rate, blood pressure, and respiratory function.

1964

Norman Cousins begins laughter therapy

Journalist Norman Cousins, diagnosed with ankylosing spondylitis, began watching comedy films as part of an unconventional treatment regimen. He found that 10 minutes of hearty laughter provided up to two hours of pain-free sleep.

1979

Anatomy of an Illness published

Norman Cousins published Anatomy of an Illness as Perceived by the Patient, documenting his recovery through laughter and positive emotions. The book became a bestseller and prompted serious medical research into the mind-body connection.

1995

Madan Kataria founds Laughter Yoga

Dr. Madan Kataria, a physician in Mumbai, India, started the first Laughter Yoga club with five people in a public park. The practice combines intentional laughter exercises with yogic breathing and has since spread to thousands of clubs worldwide.

2000s

Clinical laughter research expands

Peer-reviewed studies confirmed that laughter reduces cortisol levels, increases endorphin production, strengthens immune function, and improves cardiovascular health. Research also demonstrated that the body responds identically to simulated and genuine laughter.

How to Celebrate National Let’s Laugh Day

1

Try a Laughter Yoga session

Find a local club or online session through the Laughter Yoga International network. Sessions combine guided laughter exercises with deep breathing and typically last 30 to 45 minutes. No prior yoga experience is needed.
2

Watch the comedy that started a medical field

Norman Cousins credited Marx Brothers films with part of his recovery. Watch Duck Soup or A Night at the Opera and see if the 1930s humor still works. Cousins found that even dated comedy produced genuine physiological effects.
3

Time your laughter response

Watch something funny and use a stopwatch to measure how long you actually laugh. Most people overestimate. The average adult laughs approximately 17 times per day, and each episode lasts only a few seconds.
4

Read about gelotology

Gelotology, the scientific study of laughter, documents how humor affects the body: reduced cortisol, increased endorphins, improved cardiovascular function, and strengthened immune response. The field spans everything from the neuroscience of humor to the measurable effects of a single laugh.
5

Make someone else laugh today

Share a joke, send a funny video, or tell a story that made you laugh this week. Laughter is inherently social: research shows people are 30 times more likely to laugh in the presence of others than when alone.

Why We Love National Let’s Laugh Day

A

Laughter has measurable physiological effects

Clinical research has documented that laughter triggers the release of endorphins, the body's natural painkillers, while reducing cortisol, the primary stress hormone. Studies published through the NIH show that laughter increases immune cell production and improves cardiovascular function. These are not subjective reports but measurable biological responses.
B

The body cannot tell the difference between real and fake laughter

One of the most surprising findings in gelotology is that simulated laughter produces the same physiological benefits as spontaneous laughter. This discovery, validated through multiple clinical studies, is the scientific foundation of Laughter Yoga and therapeutic laughter programs used in hospitals, senior care facilities, and corporate wellness programs worldwide.
C

It connects to a field of medicine born from one patient's experiment

Norman Cousins's self-directed laughter therapy in 1964 was controversial, but it led to the establishment of the Norman Cousins Center for Psychoneuroimmunology at UCLA, one of the first academic centers dedicated to studying how emotions affect physical health. National Let's Laugh Day marks a subject that helped create an entire branch of medicine.