Can someone explain to me why laughing hard can lead to crying?

It may be the same reason that every time I cough, I then sneeze.

Screwy sinuses.

“Crying is a more complicated process than one would at first imagine. First of all, there are really three different types of tears. Basal tears keep our eyes lubricated constantly. Reflex tears are produced when our eyes get irritated, like with onions or when something gets into our eyes. The third kind of tear is produced when the body reacts emotionally to something. Each type of tear contains different amounts of chemical proteins and hormones. Scientists have discovered that the emotional tears contain higher levels of manganese and the hormone prolactin, and this contributes in a reduction of both of these in the body; thus helping to keep depression away. Many people have found that crying actually calms them after being upset, and this is in part due to the chemicals and hormones that are released in the tears.

How then actually do we cry? The psychic tears (or emotional tears) require an emotional response, or trigger to be activated. This response can be caused by an outside source, either pain or loss of love, etc., or from an inside source (self-realization of one’s life and others). When emotions affect us, the nervous system stimulates the cranial nerve, in the brain and this sends signals to the neurotransmitters to the tear glands. Thus, we cry .The largest tear gland, the lacrimal gland produces the tears of emotion and reflex. Many believe that the body, in times of emotional stress, depends on this gland to release excess amounts of chemicals and hormones, returning it to a stable state.”

Source

Explains it much better than my first failed attempt.

It’s just the way it is! It’s different for everybody of course. Some people can wet themselves or even pass gas from laughing so hard.

Hmmm. In me, laughing that hard leads to an inability to breathe. Which leads to watering eyes.

Crying and laughing use the same kind of huccupping movement and are physically very similar. So if I’m laughing so hard I can’t breathe and tears are coming out of my eyes, it could seem like crying. But it’s still laughing.

@Plucky Throughout college I had this quote on my quote board: “Tears are the antifreeze for the soul.” I absolutely loved that quote—now… I learn there’s a biological basis for that! Even better!

So, if laughter’s the best medicine and you add crying while laughing, would that be a medical marvel?

uncontrollable laughter leads to crying and if the saying or what you hear really is too funny.
Nothing bad just happens to some people who think everything is funny or the ‘yea funny’ to be OMIGOSH so damn funny nd lough-out-loud for hours, and cry.