Have you ever experienced a momentary loss in strength when you laugh? Many people also express their lack of motor control for a few moments after laughing or experiencing extreme emotions. Scientists now have some answers as to why this happens. It turns out that laughter can trigger a reflex in your body that weakens your muscles, almost to the point of collapse. This isn't just a feeling; it's something that can be measured using electrical signals to see how your muscles react. Laughter Can Make You Weak! Researchers in the Netherlands, whose findings were published in the medical journal The Lancet, 1999 made this discovery while studying a condition called cataplexy. Cataplexy causes people to suddenly lose muscle control and collapse during strong emotions, especially laughter. They were comparing people with cataplexy to a control group without the condition. While studying the muscle reactions of the control group during different emotions, they unexpectedly found that laughter caused a significant weakening of muscles. Testing the Laughter Effect The researchers used electrodes to measure the H-reflex, which is a way to see how muscles contract. They showed the control group, which included fellow researchers and medical students, various slides to evoke different emotions. Instead of being nervous, the participants were relaxed and joking around. That's when they noticed something interesting, when the participants laughed, their H-reflex almost disappeared. To confirm their findings, they conducted another experiment, this time intentionally trying to make people laugh. Sebastiaan Overeem, a medical student known for his humor, was tasked with getting the new group of subjects to laugh. He used jokes, including ones about Belgians, which were particularly effective. Every time a subject laughed, their H-reflex significantly weakened, proving that laughter does indeed cause a measurable muscle weakness. How Does Cataplexy Affect Us? The Cleveland Clinic explains that it happens while you're awake, and it's a common sign of a sleep problem called narcolepsy. Narcolepsy makes you feel so sleepy during the day that you can't stop yourself from falling asleep, even when you don't want to. Sometimes, cataplexy can also be caused by very rare problems you get from your parents. When you have a cataplexy attack, your muscles can get a little weak or very weak. Sometimes, only a few muscles get weak, like the ones in your face, making your jaw drop or your head nod. However, sometimes, all your muscles get weak, and you might fall down. The important thing is, you stay awake and know what's happening during the attack. This is different from fainting or having a seizure, where you lose consciousness. Cataplexy attacks usually only last for a few seconds or minutes, and then your muscles go back to normal on their own. How often they happen is different for everyone. Some people have many attacks every day, while others only have a few attacks each year.