How quickly can your brain atrophy?

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A great way to appreciate “if you don’t use it, you lose it” is to be casted up. Less than a couple months later, take the cast off, and that limb looks like carnage.

That doesn’t tell the whole story though. A broken bone might mean being in a cast for 6-8 weeks. What if things happen even quicker than that? Where you don’t see it sooner only because the cast is in the way?

Things do happen quicker than 6-8 weeks. Much quicker.

After only a couple weeks in microgravity and astronauts can already be 10% weaker! If you’re a 300 pound squatter, to only be a 270 pound one two weeks later is a big deal.

After only a couple weeks astronauts have balance issues too. For all the bitching we humans do about how slowly the body adapts, we concurrently complain how quickly we adapt when it’s in a direction we don’t want #HaveTheCakeOrEatIt.

Let’s look at something else which can atrophy: the brain.

Dementia and Alzheimer’s being the most relevant examples. This is a crucial point. Your brain can, does, and likely will, get smaller.

This is no different than any muscle. As we get older, they, and the brain, tend to get smaller, and most importantly, that leads to them getting weaker. Off to all the brain games we go.

But astronauts are already engaging their brain. Sure, they might not load their body as much, but they damn well are loading their brain, right? Their survival instincts are on overdrive, they are as filtered a population in perhaps all of human existence, operating at the limits of what humans consider our brain power.

Then why do their brains get smaller???

-> There are a lot of issues with this study, as the authors point out. But space studies exemplify having to go with what we have.

All the blue shaded areas are where gray matter decreased. All the red to yellow are where gray matter increased. As you can see, you have to go hunting to find the red / yellow, but the blue is obvious.

This is for astronauts who spent either six months in space, or two weeks. The longer you’re up there, the more gray matter you lose, but after only two weeks you’re already losing some. Sounds like what happens to our muscles and bones, no?

Again, astronauts are using the brain a ton! By conventional standards, would we classify anybody as using their brain more? But what aren’t they doing? Using their body as much.

They’re not walking as much, they aren’t resisting force as much. Not unless we make up for this with exercise. What happens if we do that? We can mitigate the negative brain symptoms, such as balance issues.

–Exercise as potential countermeasure for the effects of 70 days of bed rest on cognitive and sensorimotor performance

The effects are very similar for those of us on Earth, who take being sedentary to the extreme:

Worried about dementia? Stop thinking and start moving.

Want astronauts to have full brain power? They have to get moving.

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