Everybody makes such a big deal about how tough business school is, it’s really BS - an image put about somehow to make it seem more aspirational and more of an achievement by those who have graduated. I loved business school, I studied hard and played hard, much more than my under grad - but I have also never been fitter than I was after two years studying for the MBA!!
Your time at business school will be way more flexible than during your career post business school. So if you plan to continue to train and compete after graduating then just get used to juggling lots of priorities now!!
If you can’t do this whilst at business school then you will really struggle later. This will only get harder once real life hits post graduation.