Why Do We Hiccup? The Science Behind That Sudden ‘Hic’

Almost everyone gets hiccups. They can appear after eating too quickly, drinking a fizzy drink, or even laughing at the wrong moment. Usually, hiccups disappear within a few minutes and are harmless.

But have you ever wondered what actually causes that sudden ‘hic’ sound?

An involuntary spasm of the diaphragm causes hiccups, the dome-shaped muscle that helps us breathe. When the diaphragm suddenly contracts, air is quickly pulled into the lungs. Almost immediately, the opening between the vocal cords, called the glottis, closes, producing the familiar ‘hic’ sound.

What Happens In The Body During A Hiccup?

A review published in the journal 'BioEssays' explains that normal breathing involves the diaphragm contracting and relaxing in a controlled way.

During a hiccup, however, the diaphragm contracts suddenly and involuntarily. This is followed by a rapid closure of the glottis.

The process can be described simply as:

Diaphragm suddenly contracts → air rushes into the lungs → glottis closes → hic sound

The hiccup reflex involves several nerves and areas of the brain that coordinate breathing. The phrenic nerve, which controls the diaphragm, and the vagus nerve are among the pathways involved.

Why Do We Get Hiccups?

There is often no single clear reason. Hiccups can happen when something temporarily irritates or stimulates the nerves involved in the reflex. Common triggers include:

• Eating too quickly
• Eating a large meal
• Drinking fizzy drinks
• Drinking alcohol
• Sudden changes in stomach temperature
• Swallowing air
• Laughing or becoming excited
• Emotional stress
• Sudden changes in temperature

A distended stomach after a large meal may irritate the diaphragm or nearby nerves, making hiccups more likely.

Also Read: Why Do We Yawn? The Surprising Science Behind This Everyday Reflex

Why Do Hiccups Happen After Eating?

According to the British Journal of General Practice, eating quickly or eating too much can cause the stomach to expand. Fizzy drinks can add gas and further increase stomach distension.

Swallowing air while eating or drinking can also contribute.

This may stimulate the nerves involved in the hiccup reflex, resulting in repeated contractions of the diaphragm.

This is why slowing down while eating, avoiding very large meals and limiting fizzy drinks may help reduce some episodes.

Can Stress Cause Hiccups?

Yes, emotional changes can sometimes trigger hiccups.

Excitement, nervousness, sudden laughter or stress may affect breathing patterns and stimulate the hiccup reflex.

However, getting hiccups during a stressful situation does not necessarily mean stress is the underlying medical cause. Often, several triggers can occur together.

Why Do Some People Get Hiccups More Often?

Some people may simply be more prone to hiccups. Eating habits, drinking patterns, and individual sensitivity of the nerves involved in the reflex can all play a role.

Frequent hiccups can also occasionally be linked to an underlying medical condition or medication, particularly when they occur without an obvious trigger or last for a long time.

How Long Do Hiccups Normally Last?

• Most ordinary hiccup episodes are short-lived and stop on their own within minutes.
• Occasionally, however, hiccups can continue for much longer.

Doctors generally classify hiccups lasting more than 48 hours as persistent hiccups. Those lasting for more than a month are known as intractable hiccups.

Long-lasting hiccups are uncommon and may interfere with eating, drinking, sleeping, and speaking.

When Can Prolonged Hiccups Be A Warning Sign?

Hiccups that continue for more than 48 hours should be discussed with a doctor, particularly if there is no obvious trigger.

Persistent hiccups can sometimes be associated with conditions affecting the brain, nerves, chest or digestive system. Certain medicines and metabolic problems can also cause prolonged hiccups.

A doctor may ask about other symptoms and review medications before deciding whether further tests are necessary.

Seek medical advice sooner if prolonged hiccups occur alongside symptoms such as severe chest pain, difficulty breathing, weakness, confusion, severe abdominal pain, or other significant changes in health.

Can You Stop Hiccups Quickly?

There is no guaranteed method that works for everyone.

Some people find that slowly sipping cold water, briefly holding their breath, or breathing slowly and steadily helps interrupt the hiccup reflex.

However, many popular remedies have limited scientific evidence behind them. Methods that involve choking, frightening someone, or swallowing potentially dangerous substances should be avoided.

If hiccups are caused by eating too quickly or drinking fizzy beverages, avoiding these triggers may help prevent another episode.

Are Hiccups Dangerous?

For most people, hiccups are completely harmless and are simply a temporary reflex.

They become more important when they are unusually frequent, last for a prolonged period, or interfere with normal activities such as sleeping, eating, or breathing.

A short episode after a large meal or a fizzy drink is generally nothing to worry about.

Final Word

Hiccups happen when the diaphragm contracts involuntarily, followed by the sudden closure of the glottis, creating the characteristic hic sound. Eating quickly, overeating, fizzy drinks, alcohol, swallowing air, laughter, and sudden emotional or temperature changes can trigger them. Most hiccups disappear within minutes without treatment. But if they continue for more than 48 hours, keep returning without an obvious reason, or occur with other concerning symptoms, medical advice is important to identify the underlying cause.