Originally Posted by oleg232000

I personally do 3 hour rides multiple times a week with a good amount of climbing and exertion and I never take extra fuel, besides a water bottle, and even then sometimes I go the whole ride without taking a sip. I do fuel up before the ride though, but never during. I've went 5 hours without a single calorie and felt fine and could keep going. But to the OP, were you at any high elevation by any chance? And did you consume caffeine or an abnormally large amount of caffeine prior to the ride?