It has certainly happened to you too, but do you know why we hiccup? Hiccups are sudden contractions of the powerful muscle in your chest responsible for inhaling and exhaling air (the diaphragm), caused by an internal irritation. These contractions cause air to enter abruptly but at this time the air passage to your lungs is closed by a little flap called the epiglottis. So, air hits this closed passage and produces the 'bump' feeling of the hiccup. Hiccups can usually be cured by breathing deeply or holding your breath but there are known cases when people continued to hiccup for entire decades!