I was a spectator at the Tour of Utah last year. The first stage was about 125 miles, with >95 degrees heat and 9,000 feet elevation gain. It was hard just to wait by the finish line to watch. And it was just the first day!
PEDs have been part of the sport for a very long time
(1903, at the beginning of The Tour de France) among other reasons, because it's so ridiculously hard.