Son bumps his head all the time

My son is one and he is a very active child. He bumps his head almost everyday and gets a knot. I try to prevent him from bumping his head so much but it seems like nothing is working. My mom told me to stop letting him bump his head and I try but he’s loves to play wild. I feel terrible when he bumps his head. I constantly tell him to sit down and stop but that doesn’t work. I’m starting to feel like a terrible mom for not being able to control my child. I’m thinking about getting him a helmet. Any advice?