So, what’s the deal with hiccups? Everyone has hiccups. We start having hiccups before we are born. Yup, while floating in our mom’s tummy we are hiccuping away. Why do we have them and what makes them go away? The real answer is that science really hasn’t explained why we get hiccups. There are things that have a clear association with leading to hiccups, but it isn’t fully clear why that is. But there are some theories out there and we’ll discuss those.
But let’s start by talking about what a hiccup actually is. There is a thin sheet of muscle that spans the bottom of the rib cage; separating the abdominal and thoracic cavities. This is called the diaphragm. When we have hiccups it is because this muscle begins to spasm which causes the lungs to expel a short burst of air. Once that air has passed the vocal cords, through the glottis, they snap shut and make the classic hiccup noise.
Hiccups are considered to be a somatic reflex arc. This means that there is a stimulus which triggers an involuntary response of a muscle. A reflex is information that is processed in the spinal cord rather then through the brain. Another example of a somatic reflex: someone taps your knee and your leg jerks. There is a stimulus (the tapping) and a muscle response (jerking leg). Hiccups work the same way.
There are 2 kinds of hiccups: benign and pathological. Benign hiccups are those that most of us experience. They come in short bouts and are little more then annoying. Pathological hiccups are those that last longer then 48 hours without interruption.
Let’s start by talking about the benign hiccups, which we will simply call hiccups from here on. It really isn’t clear why we have these. There is a theory that poses that it is a remnant of amphibian respiration, but this is not a widely accepted explanation and is questioned because it does not fully explain the process. However, those who support this theory present the similarity of the process as evidence. Amphibians gulp air and water over their gills to breath in a similar reflex. They also cite fetal development as evidence. A fetus begins to have hiccups before they have fully developed lungs. Additionally, pre-mature infants hiccup 2.5% of their time which again correlates the underdeveloped lung with an increased frequency of hiccups.
When considering the cause of hiccups, it is important to note that only mammals have hiccups. This suggests that it has an evolutionary advantage to mammals that it would not have for other types of animals. One thing that mammals have in common is breast feeding their infants. Infants have more frequent hiccups than adults. Research reflects that the most common stimulus for infant hiccups is the presence of air in the stomach. This air is expelled during the hiccup reflex.
However, that does not fully explain why we have hiccups in response to other stimuli. We can clearly define what kinds of stimuli lead to the reflex of hiccups, but we cannot explain why that reflex exists and why those stimuli trigger it.
What stimuli cause hiccups?
1. Eating too much
2. Eating too fast
3. Alcohol consumption
4. Carbonated beverages
5. Sudden temperature changes in the stomach
6. Swallowing air (which often happens when sucking on hard candy or chewing gum)
7. Hard, prolonged laughter
8. Fatty or Spicy foods
11. Sudden Excitement or Emotional Stress
The important thing to note about this list of stimuli that produce the hiccup reflex is that all of them involve an irritation or stimulation of the stomach. Number 11 is the one that might seem to be an exception to that statement, but it’s not. Generally speaking, a strong emotional response causes the release of epinephrine. This is what our bodies use for fight or flight. And the old adage “rest and digest” is true. It takes energy to digest our food and this becomes difficult when our bodies are busy doing something else. This disrupts the acids, enzymes, and functions of your stomach and intestine, which leads to nausea-related symptoms. This is why many people with anxiety or stress experience nausea. This is called stress vomiting. Thus there is a clear connection between a person’s emotional state and the status of the stomach which makes it unsurprising to see it on the list of stimuli that trigger hiccups.
With all of these stimuli being related to the stomach, it further supports the idea that hiccups are related to air clearance from the stomach which is essential for good feeding for an infant. This is why we burp our babies and why they often want more food after burping. Once the air is gone, there is more room for food.
Now that we’ve talked about why we get them, let’s look at what we can do to make them stop. I personally recommend trying to prevent them in the first place. There are several things you can do to help prevent hiccups:
1. Eat small meals slowly.
2. Avoid alcohol, nicotine, fatty foods, spicy foods and carbonated beverages.
3. Eat foods as close to room temperature as possible.
4. Avoid swallowing air. Don’t chew gum or suck on hard candies.
5. Only take medications with the advice of your doctor.
6. Maintain emotional health with good stress management.
But what to do once they’ve struck? All the weird (and effective) remedies out there to treat hiccups target either retention of carbon dioxide or the stimulation of the nasopharynx or vagus nerves. Why does this work?
Retention of carbon dioxide triggers the oxygen drive which demands that the diaphragm begin to rhythmically and smoothly move in order to draw in air. The oxygen drive is stronger then the hiccup reflex because of how important oxygen is. In order to safely retain some carbon dioxide, try one of these tricks:
1. Hold your breath for as long as you can
2. Breath into a paper bag
Stimulation of the nasopharynx or vagus nerves causes other messages to come into the nervous system which can over ride the hiccup reflex (we think). To safely stimulate one or both of those nerves, try one of these tricks:
1. Quickly drink a large glass of water. Which also means you are holding your breath…
2. Have someone startle you
3. Stick your tongue out and pull on it firmly
4. Bite into a lemon
5. Gargle water
6. Put a teaspoon of sugar onto the back of your tongue where your sour taste buds are
7. Tickle the roof of your mouth with a Q-tip
But, I have to mention that there is usually no obvious cause for a bout of the hiccups. They just come and then go, leaving scientists perplexed.
However, there are times that hiccups are caused by a pathological process. These hiccups are accompanied by other symptoms while benign hiccups come without other symptoms. The most important distinguishing factor is that benign hiccups are short lasting while pathological hiccups last without interruption for more the 2 days. If your hiccups have been holding on for more then 2 days, are interfering with your ability to eat, drink, sleep or breath THEN GO SEE YOUR DOCTOR.
By definition, pathological means that there is something going on that is not a normal function of the body. So, it is important to understand that when discussing pathological hiccups we are discussing hiccups that are caused by an underlying illness. The causes of pathological hiccups are not the same causes as benign, every day hiccups.
Pathological hiccups have 3 causes:
1. Nerve damage or Irritation
2. Central nervous system disorder
3. Metabolic Disorders (often caused by drugs)
Pathological Processes leading to hiccups that are caused by nerve damage or irritation:
1. Something touching or pressing on the ear drum such as a foreign body or a growth in the ear.
2. A tumor, cyst, goiter in the neck
3. Gastric esophageal reflux disease
4. Chronic sore throat or laryngitis
It is important to note that not all of these have a clear connection to stimulation or irritation of the stomach.
Pathological Processes leading to hiccups that are caused by Central Nervous System disorders:
3. Multiple Sclerosis
5. Traumatic Brain Injury
6. Brain Tumors
Any time the structure of the brain is changed, it will change the functions of the body.
Pathological Processes leading to hiccups that are caused by Metabolic disorders:
5. Electrolyte Imbalances
6. Kidney Failure
I’m not going to get into how each of these lead to having pathological hiccups. The important thing here is that when we change with chemistry of our bodies we are changing the chemical mix in our brains. Our brains function based upon chemical signals. When our chemical mix changes it is possible to cause confusion in the chemical messages in the brain which will alter brain function.
Some final closing tidbits:
1. Men are more likely to have pathological hiccups then women
2. Benign hiccups effect both genders equally
3. Abdominal surgery increases your risk for benign hiccups
4. A diagnosis of mental illness increases your risk for benign hiccups
5. Having hiccups can impair wound healing.
6. The longest recorded bout of pathological hiccups lasted 68 years without interruption. That would suck!
Hope you found this interesting!
At the top of the page, you’ll find a tab “Contact the Piggie”. Click on that and drop me a medical question or a request to have a medical diagnosis explained. I’ll do my best to give you useful and interesting information.
Thank you Misroch, for the question that led to this post!
Some references and further readings: