Do you drink anything while riding? You really need to drink at least water while cycling at anything more than a very easy effort.
Swig is generally less than a gulp Probably about the amount of fluid in the neck of a long neck beer bottle.
I gulp. In fact I take a two or three good gulps and a 24 fl.oz. bottle will last me about 50 minutes in the current hot weather we have here. Though yesterday I did stretch two bottles out long enough to last a 2hr 8 minute ride.
Generally every 10 minutes that I ride, I'm drinking from my bottle. Whether it's water or mix. Usually its mix so I get a steady supply of carbs.