Lose Power In Legs And Neck In A Fit Of Laughing, Don't Make A Sound, Have A Deep Internal Laugh. What Causes This?
In a very small percentage of individuals - less than one percent in fact - the act of laughing can cause an activation of the central nervous system. This activation can cause a reflex relaxation in muscles in the arms, legs and sometimes the neck.
This degree of relaxation or loss of power as you put it, is very rare.
At the same time let me reassure you that this does not reflect anything pathological. This will not cause you any long term detriment and will not limit any quality of life for you.
Less than 1 percent of people have this degree of reflex when laughing.
Again this is not something worrisome at all.
Thanks again for your query. I hope you found my response to be helpful and informative. If you have ay additional concerns I would be happy to address them.
Sincerely,
Dr. Galamaga