First, the explanation. What is called heartburn generally occurs when the powerful stomach acids escape the stomach and move (backwards) up into the supply tube (esophagus) toward the mouth. That is not supposed to be able to happen because there is a sphincter (valve) at the bottom end of the esophagus where it enters the stomach which is supposed to close once food has passed through.
Even if that sphincter loses its ability to seal completely, if we are upright (as generally is true during the daytime) gravity tends to keep food and stomach acids down in the stomach, where it is very unusual that any acid can then get up into the esophagus to cause discomfort or damage.
HOWEVER, when you sleep, gravity no longer can help! If that sphincter leaks at all, then some stomach acid can leak into the esophagus, which causes all the problems. So people buy immense amounts of chemicals which neutralize stomach acids. It seems clear that the stomach does not appreciate that, as the acids inside the stomach are also weakened and therefore digestion is slowed! (No one that sells such products seems to ever mention that side effect, as they are simply selling products to counteract the small amount of stomach acid that gets up into the esophagus!)
(Which is part of my personal aversion to all medicines, because they generally have side-effects in addition to what they are supposed to accomplish!)
So, the new idea? Either buy several of those cheese-wedge-shaped pillows, or build a plywood and 2x4 wedge, the width of your bed, 18" wide and 6 or 8" high. I lifted up the upper edge of the mattress to place the wooden wedge UNDER it (with the tallest part against the headboard).
The result of this is that I sleep with my head a few inches ABOVE the level of my stomach, and more specifically, my esophagus is an inch or two higher than it would be when I would lie on a flat bed. In my case, it immediately and entirely ended all heartburn or similar pain. I choose to believe that it also eliminates whatever damage that stomach acid had been doing to my esophagus.
There is only one downside to this. The bed looks somewhat odd! The sheets, even fitted sheets, still are the same, as are blankets. Only the appearance of the bed is different.
I experimented with higher angles, but found them undesirable for two reasons. One was that I tend to roll around a lot and I would wake up having slid down the hill! (Which means the solution did not apply after that happened. The slope I describe here does not seem to cause such sliding.) The second is also related to my rolling around, where a steep slope seemed to be less comfortable for lying on my stomach, as my back was then bent backwards. Again, with this gentle slope, that has never been a noticeable problem now.
You may be aware that Hospital beds generally have motorized mechanisms to enable raising the bed in such a way, so they apparently agree! But instead of buying a $5,000 motorized bed, I am describing here a $20 way to accomplish the desired change!
( http://mb-soft.com/public/index.html )
C Johnson, Physicist, Physics Degree from Univ of Chicago