Hey. I’ve had car rides that’ve seemed to do me harm, but I tend to chalk the symptoms up to bumps or jostling rather than acceleration. It was only when I was already in a bad way and went on a very long trip over and down mountain roads that I had feelings like the ones you describe.

However... I have definitely found this to be the case with airplanes and high-speed trains. Turning to the side seems to help me on the train. My working theory is that there’s less room for the brain to travel in that position... or else that my injury was more front-to-back than left-right.

Like most triggers, acceleration is a tough one to convince friends and family of. It’s not like the effects leave you totally incapacitated, so I’m not sure how this could ever be confirmed. I wouldn’t feel comfortable sharing my thinking on this outside of this forum.

I share your concern about the effects of subconcussive forces over time, but I do think you can expect a completely recovery from the (subtle) effects of being in a fast-moving vehicle now and then. I’ve been on a downward trajectory for a while, but, even now, when I’m well, I’m really well (as in near-enough to whole as to be acceptable). I don’t see how that would be possible if my past subconcussive experiences were all leaving a mark/taking a pound of flesh.