Water has a specific heat capacity of about 4.2 Kilojoules per kilogram per degree Kelvin, so it would take about 6 Kilowatt Hours of electricity to heat 100 Litres of water from 15 degrees centigrade to 65 degrees centigrade. As a standard immersion heater is 3KW, so it would take 2 hours to heat 100 Litres of water.
Drinking a large amount of carbonated drinks at bedtime can also cause hiccups, as the air in these drinks can distend the stomach. Consuming a large amount of alcohol before going to bed is another possible cause of hiccups during sleep. The excessive amount of alcohol can cause the stomach to distend.
Many conditions can cause this irritation and result in hiccups, including eating too fast and swallowing air, chewing gum, smoking, eating or drinking too much, strokes, brain tumors, damage to the vagus or phrenic nerve, some medications, noxious fumes, anxiety and stress, and in babies, hiccups may be associated with crying, coughing, or gastroesophageal reflux .