We’re all familiar with the sensation- an uncontrollable jerk of our diaphragm and an involuntary noise, stifled or not, that gives the condition its name. Hiccups are ubiquitous amongst mammals of all ages, but it may surprise you to learn that even in 2024, our understanding of them is somewhat lacking.
Hiccups are the result of a reflex arc in our nervous systems, carrying a signal from our diaphragms to our brains and back. First, your diaphragm contracts, causing air to rush into your lungs, then your glottis clamps closed, causing the hic sound of hiccups. Interestingly enough, the hiccup reflex is protective. Without it, we would hyperventilate. The precise complexities of that arc are yet to be elucidated, but within them lies the key to stopping hiccups: interrupting the arc.
The causes of hiccups are varied, but typically come down to a rapid distension of the stomach, either by food or by air. That’s why you can get hiccups with carbonated drinks, after a big meal, or in cases when you may be swallowing air, like when crying. Other irritants to the stomach, like spicy foods or alcohol, can induce hiccups too.
Luckily, the majority of hiccup cases are short-lived and resolve on their own. However, a bout of hiccups is considered persistent if it lasts longer than 24 hours, and intractable at 48 hours. The causes of intractable hiccups are diverse – a consequence of the interaction net between the hiccup reflex arc and other bodily systems. Diabetes, tuberculosis, malaria, and herpes can be complicated by long-lasting hiccups. Being intubated, receiving general anesthesia, or taking drugs like dexamethasone, diazepam or some chemotherapy agents can cause them. Hiccups have even been reported as an atypical presentation of SARS-CoV-2!
Experts have a few theories for why mammals hiccup. One is that it’s a leftover trait from our earlier amphibian respiration. Another theory is that young mammals evolved to hiccup as a way to consume more milk. Hiccups, brought on by trapped air in the stomach, would expel air from the digestive tract, making more space for milk. And another is that hiccups serve to help fetuses’ brains ‘map out’ the body, especially their diaphragm – a necessity from birth.
Even if we don’t entirely understand why hiccups happen in a physiologic, or evolutionary, sense, we do at least know something about how to stop the damn things!
The key to ending a hiccup session is interrupting the reflex arc, which, a lot of things can potentially do. Drinking water, holding your breath, a scare, sneezing, and so many more home remedies seem to work for some people sometimes. At the same time, hiccups do tend to stop randomly on their own, making it easy to attribute their stopping to something else.
A few methods have been investigated scientifically. One review states that “the simple application of a nasogastric tube may successfully treat the hiccups”, but that’s not typically a home remedy. A very interesting study found that hiccups stopped in patients when the inhaled CO2 reached over about 50 mm Hg, which, while breathing in a plastic bag, took just over 3 minutes.
Dr. Ali Seifi, the Director of the Neurological Intensive Care Unit at the University of Texas Health Science Center has actually patented a hiccup cessation device, called a Forced Inspiratory Suction and Swallow Tool. Branded as Hiccaway, you can buy one for about $18.
The device is essentially a wide straw with a valve, such that high suction is needed to draw liquid up it. The logic is that the sucking causes your diaphragm to contract, followed immediately by the closure of the epiglottis. This “activates the Phrenic and Vagus nerves simultaneously, allowing the brain to reset and stop the hiccups” according to the website.
Hiccaway was offered to volunteers worldwide, and 249 of their experiences were recorded through an online survey. 92% of hiccup sessions were stopped, according to the results, with 90% of respondents rating it favorably compared to home remedies.
There isn’t a massive amount of scientific literature evaluating remedies for hiccups, except when it comes to acupuncture. Despite the plentiful studies, however, a 2013 Cochrane review found that four of them “had a high risk of bias, did not compare the intervention with placebo, and failed to report side effects or adverse events for either the treatment or control groups.” A 2020 systematic review similarly concludes that “there is limited evidence supporting nonpharmacological interventions for hiccups in adults.”
If you are ever plagued by thoughts that your hiccups will never stop, rest assured there are some pharmacological interventions for intractable hiccups that can help you rest again. Again, there isn’t a massive body of literature on what drugs work best, but baclofen, metoclopramide, gabapentin and chlorpromazinehave been successfully used many times.
You could always try the less conventional, although decidedly more fun method of one 40-year-old patient, for whom even metoclopramide and chlorpromazine didn’t work. He found that when having sex with his wife, upon the moment of his ejaculation, all hiccups would cease.
