Yes, I took a bad fall at fairly high speed (caught my handlebar on a tree) on a mtb trail a few years ago, and my head went down hard on the trail (on the side of my head). The headache was gone by morning, but my neck on the other side from where I hit was sore for at least a week afterwards, kind of like a whiplash. Fortunately, it healed up fine. And yes, I replaced the helmet.