To be fair, studying 8 hours a day is difficult, if you've never, ever done it before. That was a new concept, and something that sounded crazy. In medical school, if I did that every day, I wouldn't have been where I am now(due to burning out and crashing). I spent countless hours studying to make it through...but there is some bias, as I am a very slow reader, and thus probably spent more time going through a packet of notes compared to the average student. For boards, I was pushing 8 hours daily to stay afloat....and that was the worst experience in med school...it was torture, especially cause my attention dropped halfway through. Plenty of times I felt like I wanted to just stop...but had to keep trucking through, since failing was not an option. I do commend the people who CAN study that long for med school exams and especially the boards. For me, daily studying was needed to pass med school classes, but it was broken up into hour sessions 5-6 times a day. That way, I wouldn't have a mental collapse.
In undergrad, I've never experienced the idea of studying everyday, or doing 5 hours of studying when there wasn't a test the next day. I know lots of classmates who barely studied in college who had to revamp their strategy to deal with the insane volume of med school. Really, the first year is an adjustment from the undergrad state of things to the med school state. Both require lots of hard work, but the latter has much more volume...