Hiccups occur due to involuntary spasms of the diaphragm, the muscle located below the lungs that helps with breathing. When the diaphragm suddenly contracts, it causes a quick intake of air, which hits the vocal cords and makes them close, producing the characteristic "hic" sound. This reflex is known as singultus. Common causes of hiccups include eating too much or too quickly, drinking carbonated beverages or alcohol, sudden temperature changes, swallowing air (such as when chewing gum), emotional factors like stress, excitement, or nervousness, and irritation or stimulation of the nerves controlling the diaphragm, especially the phrenic nerve. In some cases, hiccups can be caused by medical conditions, nerve damage, or certain medications. Most hiccups are short-lived and harmless, but persistent hiccups lasting more than 48 hours can indicate underlying health issues requiring medical attention. The exact reason why hiccups happen suddenly in many cases remains unclear, but the above triggers are well recognized.