Getting hiccups after laughing is a common occurrence, though it becomes annoying if it persists for more than a minute or two. Sometimes the reason people get so frustrated with hiccups is because they don’t understand what causes them. Knowing why you hiccup after laughing helps you understand exactly what is going on inside your body when it happens. If you know the cause, it is possible to prevent it from happening again.
Rush of Air to the Diaphragm
Your diaphragm helps you breathe. Sometimes when you laugh uncontrollably, or laugh for an extended period of time without taking proper breaths in between, air rushes into your diaphragm. This sudden rush of air forces your body to expel the air in an abnormal fashion, resulting in hiccups.
Air Trapped in Stomach
When laughing, it is possible for excess air to become trapped in your stomach, causing it to distend and expand. This causes stomach acid to be pushed into the esophagus. The body protects itself by producing hiccups. Additionally, excessive buildup of air in the stomach causes acid reflux, which leads you to hiccup in much the same way you belch as a result of stomach acid buildup.
Irritation of the Phrenic Nerves
The phrenic nerves extend through the diaphragm. Your body has two phrenic nerves, a left one and a right one. These nerves are what tell the diaphragm when to contract and when to relax. Simply put, without the phrenic nerves, you do not breathe. Since laughter typically produces abnormal breathing, it irritates the phrenic nerves, leading them to tell the diaphragm to contract when it is not supposed to, resulting in hiccups.
Not every cause of hiccups is scientifically or medically accepted as fact. According to the phylogenetic hypothesis, several groups of amphibians exhibit a contraction of air similar to hiccups, as a way to keep water out of their lungs. Supporters of this hypothesis believe that human beings have held onto some remnant of this behavior due to evolution. Some argue that babies need to hiccup to keep milk out of their lungs during breastfeeding. This suggests that hiccupping is, at least sometimes, an involuntary but necessary action. Supporters of this hypothesis argue that uncontrollable laughter leads to a risk of asphyxiation if hiccups are not produced as an alternative.