[analog]

I cycled competitively in my teens, and got a few ok results in my speciality (hill climb) at a national level, but not good enough to want to take it any further. Some of the friends I trained with went pro.

I trained 400 - 500 miles per week, riding anywhere from 10 to 140 miles per session. I'm 40 now and still cycle but just for pleasure and getting around now, slower than I was before but riding centuries is still no problem.

In short, I know exactly what the knock feels like.

I expect you are carb loading either the day before or in the morning before your rides, and that could easily give you enough stored glycogen to see you through a 2 hour ride.

I however was cycling to burn off fat that I'd built up during a few months of strength training, so the last thing I'm going to do is gorge on pasta the night before.