In short, it could actually kill you.
Leave it to the medical industry to find the downside to a good thing. In a Scrooge-y Christmas edition of BMJ, a peer-reviewed British medical journal, authors Robin Ferner and Jeffrey Aronson reviewed 785 research papers published since 1946 and came up with 15 unfortunate side effects from laughing. “It turns out that what is called ‘the best medicine’ occasionally causes harm,” Ferner, a clinical pharmacologist, told TIME. “Most of the time it makes people happy, but every now and again it kills them.”
Let us count the ways:
1. Weakened resolve
3. Irregular heartbeat
4. Cardiac rupture
5. Inhalation of foreign bodies (e.g. gum drops, popcorn, peppermint bark)
6. Asthma attacks
7. Increased risk for lung collapse
9. Increased chance of spreading infections due to “exhaled airflow”
10. Sudden loss of muscle tone (don’t worry too much about this one – it’s temporary)
13. Protruding hernia
14. Dislocated jaw
15. Peeing your pants (but you already knew that …)
But wait, the misery doesn’t end there. The paper also noted that if you laugh without a good reason (aka “unprovoked laughter”), you could be suffering from any number of maladies, including a brain tumor or multiple sclerosis. While the paper lists several of laughter’s benefits (most surprising: laughing all day can burn 2000 calories and “cure obesity”), it hedged on whether its reputation for lowering the threshold for seduction was a plus or a minus.
“We are very cynical, you know,” said Ferner, who conceded that despite laughter’s many downsides, “it makes us feel better and feeling better is good.”