1) Gravity. When a person is standing up, versus lying down, gravity is able to help the reflux material return to the stomach. Therefore, the reflux material can remain in the stomach longer at night, and cause more discomfort than in the daytime.

2) Distraction. People are not as distracted at night as they are in the day. Preliminary research supports the power of distraction for pain management. Many times, a person may have acid reflux-related pain in the daytime, but he or she is too busy and distracted to focus on the discomfort.

3) Swallowing. The bicarbonate in our saliva tends to neutralize the acid in our esophagus. At night, a person is not swallowing as much as in the daytime.

4) Medication. The half-life of most acid reflux medications is too short to stay effective throughout the night. My son takes acid reflux medication just before bed and by 3 a.m., the medication is completely metabolised and no longer effective. This phenomenon leads to night-time acid "breakthough."

5) Snacking. Some individuals tend to eat the "wrong" foods just before bed, which can also make reflux worse at night. Foods which are difficult to digest, like meat or raw vegetables, or greasy foods like chips or pizza can make reflux worse if eaten just before bed.