Most people have a hard enough time envisioning retirement at all, much less early retirement.

I first read about the concept of early retirement via the finance blogMr.

But we do a lousy job seeking out the risks inherent with a huge life change like early retirement.

In a recent post, he breaks down one of those risks: early retirement might dull your brain.

Researchers call itmental retirement, and it may hit harder for younger retirees.

They found that early retirees scored significantly worse than subjects from countries who retired later.

Of course, correlation is not necessarily causation, and memory tests are just one way to measure cognition.

Other scientists have pointed this out, too.

As oneresearcher told the Times:

Its quite convincing, but its not the complete story.

This is an opening shot.

But its got to be followed up.

They point to a couple of reasons early retirement might dull our cognition.

This might be a matter of use it or lose it.

They say if you want to keep your cognitive abilities, like memory,you should stay active.

The very prospect of an early retirement itself may sap the workers motivation, Brian told us.

In other words, the mental retirement effect may kick in before youve even left your job.

Ive been thinking a lot differently about my early retirement since writing

the post

, Brian said.

But the risks of cognitive decline are too great.

Of course, the answer isnt that black-and-white, either.

Not all work is mentally stimulating, for example.

And working until you die just to stay sharp sounds like a pretty depressing solution.

It might be something that affects all of us.

Or naps, said Brian.

Our plan today is to insert meaningful work into my retirement, irony be damned.

The honest answer is that Im not totally sure what that life will be like yet, Brian said.