Oddly enough I do that all on a regular basis when not riding - coffee in the morn or fruit on cereal, vitamin water mixed with water. I skipped all that to avoid stomach acid issues that I wouldn't want during my rides.. or stomachache, bathroom breaks etc.. Guess I'll throw that back in and see how it goes.. thanks for all the good info! The lightheadness happened when I stopped while on the bike, I turned to look behind me and felt slightly light headed like low blood pressure and wobbled a little. Enough that it got me a little worried. I took deep breaths for about 5 minutes, drank some water and then continued when I felt OK. This has only happened 3 times during the six months so not that bad. I had a thorough checkup couple months back. Blood, blood pressure, EKG etc. and everything was perfect, other than occasional stomach acid I mentioned before or acid reflux, nothing wrong health wise.