Wankerish speculation: Involuntary exercise may tell the body that it needs to work smarter, not harder. Hence, more brain cells. In prehistoric times, it wo

Wankerish speculation: Involuntary exercise may tell the body that it needs to work smarter, not harder. Hence, more brain cells. In prehistoric times, it would be a warning signal that risk of death or is elevated. In a world of few calories, the body must prioritize, and relies on certain signals to set priorities. Voluntary exercise doesn't indicate nearly as much danger.