I suppose it's good to investigate what exactly is happening, but surely we didn't need to do a scientific study to check if it exists? Have we now advanced emp

I suppose it's good to investigate what exactly is happening, but surely we didn't need to do a scientific study to check if it exists? Have we now advanced empiricism so far that experiencing something yourself is not enough any more? Anyway, just to make sure I suppose we'd better gather some volunteers to make sure running long distances makes people tired.