Not sure what sort of fast you’re undertaking, but the heartburn might be caused from too much water. It’s a bit of a cycle where you drink more water because you’re fasting, then get heartburn, then drink more water to soothe the heartburn. I’m definitely 100% not saying to stop consuming water, particularly because you’re fasting, but be conscious of the actual volume of water you’re drinking.
Also, if the heartburn was unbearable I wouldn’t think that having an over the counter heartburn medication would technically break your fast…
Please let us know if you do work out a cure. And congrats on 10 days fasting, that’s an achievement!
I had extreme heartburn during most of my 7 day water fast. I ended up having to take some acid reducers but every night it was so bad it would still wake me up. But reading the above comment maybe I drank too much water. If you find something that works let us know bc this is one of the main reasons I’m hesitant to start another fast