Some tracks are more hard on them than others, but I haven't heard much about any negative affects in NASCAR besides feeling dizzy or off balance for several hours after a race. Open wheel drivers commonly pull over 5 G's though in corners. Their heads are supported, but I would think your brain getting pulled to one side with that much force for over an hour can't be a net positive.

Not speaking negatively about it of course - to each their own. I raced Superbikes for eight years and you might as well throw risk tolerance completely out the window with that kind of racing.

Most are ovals, yes, but in those there's also banking involved, 30+ degrees in corners, so the idea of just turning left is missing a very important nuance to it. Outer tires are inflated more, usually 10+ PSI.

https://en.wikipedia.org/wiki/List_of_NASCAR_tracks#Track_ta...

The drivers wear a head and neck restraint to reduce the chances of injury.