Is laughter lousy for lung patients? New study says maybe

(CBS) Laughter is the best medicine? Maybe not when you have sick lungs.

While mirth makes quality of life better for people with chronic obstructive pulmonary disease (COPD), laughing out loud triggers a sharp decline in lung function - at least during the short term.

Those are the findings of a new study from Ohio State University. Researchers there used questionnaires to gauge the sense of humor of 46 COPD patients, and then tested their lung function before and immediately after watching a 30-minute video.

What did they watch? Either a home repair video or a funny one featuring Bill Cosby, Abbott and Costello, or a collection of funny home videos.

Not surprisingly, the patients who watched a funny video laughed more than those who watch the bland instructional video. But in a result that the researchers said they found surprising, the funny video patients had more trapped air in their lungs afterward - a marker of reduced lung function.

"COPD is characterized by this increased air trapping, so our hypothesis was that laughter would reduce some of that trapped air," Kim Lebowitz Feingold - a doctoral candidate at the university and the study's lead author - said in a written statement. "But in hindsight, the findings make sense. With laughter, people also are introducing an increased amount of air into their lungs compared with a normal breath. These patients have trouble getting the air out, so they are taking in more air with laughter, but they cannot easily expire that air."

A chronic, progressive breathing disorder, COPD affects more than 12 million people and is the fourth-leading cause of death in the U.S.

Is the reduced lung function transient, or lasting? Feingold said it wasn't clear.

If it lasts, it's no laughing matter.