It’s not only physically exhausting, it’s also mentally very difficult. And not just because it requires deep levels of knowledge to be good, but it also resets any preconceived notions of strength. It’s not uncommon for a new white belt male that weighs 200lbs to get absolutely waxed by a 100lbs brown belt female. I see it happen all the time. Of course, as you belt up, and gain more understanding of the sport, there are ways to utilize a size and strength advantages. But that’s secondary to knowledge.