Many people who use electronic cigarettes report experiencing short but intense bouts of hiccups, sometimes called “niccups.” This reaction is a common complaint that points to a specific interaction between the inhaled aerosol and the body’s involuntary nervous system. Vaping can trigger hiccups through a combination of chemical irritation and physical inhalation technique. Hiccups are defined as involuntary, transient spasms of the respiratory system.
What Causes a Hiccup
A hiccup, medically termed singultus, is a reflex action involving the sudden, involuntary contraction of the diaphragm muscle. The diaphragm is the large muscle beneath the lungs that controls breathing. This spasm causes a rapid intake of breath, which is immediately cut short by the abrupt closing of the glottis. This closure produces the characteristic “hic” sound.
The process is controlled by a reflex arc involving the vagus nerve and the phrenic nerve. These nerves transmit irritation signals to the brainstem, which then sends a signal back to the diaphragm to contract.
How Vaping Ingredients Act as Irritants
The chemical composition of the e-liquid contains components known to cause irritation in the airways and nervous system. Nicotine, a powerful stimulant, is a primary culprit because it directly affects the nerves that regulate muscle function. When inhaled, the nicotine aerosol stimulates sensory nerves in the throat and lungs, initiating a response similar to a cough reflex.
The two main carrier liquids, Propylene Glycol (PG) and Vegetable Glycerin (VG), also contribute to irritation. PG is hygroscopic, meaning it draws moisture, which can lead to throat dryness and irritation. This dryness and the harshness, or “throat hit,” are forms of physical irritation that can trigger the nervous system.
The Link Between Vaping and Diaphragm Spasm
The connection between the inhaled aerosol and the diaphragm spasm occurs through two main pathways: nerve stimulation and physical mechanics. The vagus nerve extends through the neck and chest and is highly sensitive to irritation in the throat and esophagus. Chemical irritants in the aerosol, especially nicotine, stimulate the vagus nerve endings as the vapor passes through. This irritation sends a signal that bypasses the normal breathing rhythm and triggers the hiccup reflex in the brainstem.
Nicotine also plays a direct stimulating role, increasing the sensitivity of the phrenic nerve, which supplies the diaphragm. This heightened nervous system state can make the diaphragm more prone to spastic contraction.
The physical act of vaping also contributes, particularly when users take deep, rapid inhalations. This technique can cause them to inadvertently swallow air (aerophagia), which leads to stomach distention. The distended stomach presses against the diaphragm and stimulates the vagus nerve branches near the digestive tract, completing the reflex arc that causes the spasm.
Stopping Vaping-Induced Hiccups
To gain immediate relief from hiccups caused by vaping, standard remedies are often effective because they interrupt the hiccup reflex arc. Temporarily holding your breath or taking slow sips of water can help calm the irritated nerves and settle the diaphragm. Drinking cold water may also help to dilute any swallowed nicotine or aerosol condensation that is irritating the stomach lining.
Prevention involves modifying both the device and the technique. Reducing the nicotine concentration in the e-liquid is a straightforward way to lessen the chemical stimulation of the nervous system. Users can also switch to an e-liquid with a higher Vegetable Glycerin (VG) to Propylene Glycol (PG) ratio, as VG is generally considered less irritating to the throat. Slowing the inhalation rate and taking smaller, gentler puffs helps minimize the likelihood of swallowing air and avoids excessive stimulation of the phrenic nerve.