Natural Killers and Laughter

Health Alert 79

We all believe the old adage “Laughter is the best medicine”. But we have mistakenly attributed this benefit to psychology alone. Now new research has revealed that laughter affects your physiology more directly than attitude or positive thinking.

We can show that laughter has an immediate and direct affect on:

• Heart rate

• Skin temperature

• Blood pressure

• Breathing rate

• Muscle activity

• Brain activity1

But most importantly (and the point of this letter to you), laughter can improve the way your body handles disease by activating your immune system.

* Killing with Kindness *

Researchers have conducted studies that show laughing gives terminally ill patients a better chance of survival. Many other studies have noted similar outcomes from laughter. Yet there was little investigation of how.

Researchers at Indiana State University recently divided subjects into two groups. One group watched a Bill Cosby comedy video. The other group viewed an intended to be serious tourism video.

Researchers took frequent blood samples and studied the Natural Killer (NK) cells in the subject. NK cells are part of your immune system. They are your body’s strongest defense against both infections and cancer.

Here’s the surprising part … The difference in physiology did not depend on if the subjects watched a comedy or not. The difference came when the subjects laughed regardless of the subject of the video.

Those who laughed during the video viewing had an increased NK cell count over those who viewed the same footage and didn’t laugh. And, this effect persisted for many hours after the laughing. 2

How can you make use of this? Well … easy … laugh. Ask you family if they’ve heard any good jokes. Go to a comedy play. Rent a funny movie. Make a note when you hear a funny joke and retell it to your friends.

The best things about laughter are:

• It’s free

• You don’t have to go down to the store to get some

• It’s fun to use

• You can have it with you at all times

• And, as you know, it’s contagious.

Al Sears MD

1 Fry W., et al The biology of humor. Humor: International Journal of Humor Research 1994; 7(2): 111-126.

2 Bennett M., et al. The effect of mirthful laughter on stress and natural killer cell activity. Alternative Therapies 2003 Mar-Apr; 9(2): 38-44.