Sorry that this isn't an answer, but I get that too! Interesting to see your post this moment as I'm sitting here trying to figure out how I'm going to go hiking with friends today, and not have to run into the woods every half hour.
I'll add that it is not only a frequency urination, but also urgenent.
I eat a pretty healthy diet, don't drink coffee, do the Water Cure , etc. and I still get it.
The only input I have it I've considered doing Richard Schulze kidney/bladder cleanse.