Ask a simple question, get a simple answer.
And, simply put, the two aren't comparable. You could more closely compare Step study and MCAT prep than an entire 2yrs of medical school on one hand and a single test-focused study period on the other.
Besides, it largely depends on your medical school. At mine, we had no more than 8hrs/wk of required sessions on average, and only another 6 of optional stuff. Exams were once every few months or so (only 5 real sets of exams in 1.5yrs of preclinicals, though we took 5 exams each time). I had time to join a sports team, do extracurriculars, watch most of Netflix (only sort of joking there), and study the way I wanted to (reading textbooks that interested me) and still have a better, more robust social life than I've had at any prior educational level.
Hell, thinking back, high school was more hectic simply from the sheer volume of required busywork, the never-ending exams, and the only-sort-of-optional extracurriculars. College was definitely more work because it straight up had more required class hours and a LOT more homework, plus a lot more individualized curriculum without as many efficient learning resources out there or as much overlap in subjects.
There really isn't that much material in medical school, and it all builds on itself nicely and is something you're (hopefully) interested in. There are concrete answers, and less of the challenging "figure out this concept that your brain literally has never conceived of before" with more straightforward "this is how this works" or "you can't reason an answer out of this, so here's the research-based approach that we use, remember it."
That being said, a lot of it you really can intuit if you understand the underlying physiology well, which can help you cut down on the straight memorization if that doesn't work for you. And again, lots of streamlined resources.
