The prep includes drinking eight glasses of water a day, as well as drinking 64 ounces of Gatorade mixed with Polyethylene Glycol 3350 powder. If you refrigerate the liquids, you'll increase the odds that you'll get the chills. Drink the water hot and the Gatorade at room temperature, and you'll be much more comfortable.
Why, yes, I do have a colonoscopy today. They've made changes in the prep since I had one six years ago. It's been much less uncomfortable so far.