The upshot is that while people shouldn't totally quit working when they retire, even at a relatively young age excessive work can hasten decline. What's more, people who worked more than 60 hours a week fared worse cognitively than people who weren't working at all. Basically, being unemployed is better than being overworked, intelligence-wise. How's that for irony!
Do we really want to make our nation dumber by insisting that more work is better? Wouldn't we all be less stressed (and smarter) if we gave out more vacation and enforced tougher overtime rules?
What does this mean for me, the go-getter who brags to my friends about how much I work?
Stop doing that! It's annoying, and it won't pay off in the long run. If you're younger than 40, it may seem like a long way away, but it'll come sooner than you think -- and this study didn't make a conclusion one way or another for adults under 40, so more research is needed. The bottom line is that, if possible, find some work-life balance that gives you time to rest and recover away from the job.