Originally Posted by
u235
Don't have an answer but... On long rides on really hot humid days (90+ sunny mid atlantic humidity). I get what feels like partial indigestion, burps, and gassy and bloated feeling every time I drink water after maybe 4-5 hours into the ride. Doesn't help when I am at a time I need water most. I started taking antacids before and a few during those long hot days and it *seems* to help but could be a placebo for all I know. I notice it far more with watered down sports drinks (I don't like them full strength) but it happens with just plain old water eventually too. In my case I am hovering around upper zone 3, not near any thresholds. I never need antacid any other time.
Are taking enough electrolytes (not just salt) that you are constantly a little thirsty? When going hard, stomach isn't happy unless its contents have about the same electrolyte levels as the stomach wall, i.e. blood levels. I see this a lot on long climbing rides, not me, others. Then they don't drink and then . . . Actually they usually bonk before they fail from dehydration. My usual fix is 2 Endurolytes and water. Never seen that not work. My guess is that you're dehydrated AND low on electrolytes. Most antacids have a high calcium content. Might not be a bad idea to take a gram of calcium before you head out.