Matthew J. Edlund M.D.

The Power of Rest

Do Stronger Muscles Mean Better Brains?

Jock or nerd? Visiting the cognitive fallacy

Posted Nov 29, 2015

Making Better Brains

For better long term brain function, is it better to work out or study Mandarin?  Be a jock or a nerd?

The popular imagination has fought this battle for several thousand years.  Who should we look to as hero – Hercules or Sophocles?  Are hedge funds and investment banks correct to choose their future partners from Ivy League crew teams, or from the nerd in the corner hatching innovative strategies, coke can in her hand?

The ancient Greeks argued you're much better off with both.  The polis'  gymnasia – what led eventually to the Western world’s forms of secondary education from high school to university, required sustained attention to mind and body. 

And recent studies argue fitter bodies mean more effective - and more long lasting - brains. But unlike some present thinking, it may have far less to do with muscles - than how you make them.

The Study

Gretchen Reynolds has been writing intelligently about exercise for a long time.  In a recent piece, she queried a study of British twins.

It was based on the TwinUK registry.  Studying twins – identical and non – lets you parse out genetic issues in a way hard to do otherwise.

This study looked longitudinally at leg strength and cognition:

Take a group of twins who were extensively studied ten years ago.  Put them back in the cognitive lab. Test the hell out of them.

Those with the strangest legs ten years ago showed the least decrease in cognitive function (aging is often not kind.)  Thinking skills were better with bigger muscles – even after controlling for fatty diets, high blood pressure, glucose levels and the like.

Predictably, one of the hypotheses put out by the research team is that muscle cells magically produce substances that improve brain function.

Here we witness the cognitive fallacy up close – that the only information biology cares about is information we can test using language,  pens and paper.  For the truth is more resilient brains may have nothing to do with bigger muscles.

It’s how you got them.

How The Body Processes Information

What happens when you try to make people more fit?

Most of the time it’s not happening in specialized gyms.  People get fitter by moving.  They walk.  They bike.  They fix their yards.  They clean dishes.  They garden.

So consider what happens when you walk down the street:

You move in tricky three dimensional space - an enormous workout for the brain.  It’s not just about avoiding cars driven by texting grannies who won’t know they’ve mowed over you until the Cadillac service mechanic checks the bumper.  You have to coordinate all senses, memory, muscle, and deep knowledge of social mores – does that guy in the jeep in the right lane look like somebody who notices the walk sign says go?

As you move your joints and ligaments will work hard.  They’ll be stressed.  They’ll be sending signals back to the brain – and everywhere else – of what they need now - and when the stress is over.

Because they’ll grow - in lots of places: the brain areas coordinating coordination.  Your ankle joint.  Your hip adductors.  Moving through space changes their lives - and their information flow.  Cells will die, fibrils will rupture, energy stores will empty.  All that will be remembered as your body rebuilds – including rebuilding while you move.

Meanwhile, your immune system – whose informational power and complexity in some ways rivals the brain – will be responding to thousands of viruses, bacteria, pollutants.  Through forced evolution, it will create billions of antibodies to face the new threats - encountering and countering a newly mutated cold virus and a carcinogenic compound popped off a Volkwagen’s exhaust. This massive response will create a different you by morning – for sleep allows much of this information to be sifted, learned – and used to rebuild a renewed you.

Do the changes in your hip muscles show up on cognitive tests?  Do the changes in immunity show up on intelligence tests?  Does your new neuromuscular coordination system show up in tomorrow’s mathematical reasoning scores?

The answer is - almost always no.  The cognitive fallacy – that measurable cognitive testing is the only thing that counts – reigns supreme.

Which leaves our understanding of what happens highly deficient.

Regenerating Information

It is hard for people to see the body as an information system.  We think of books or newspapers as information. 

The trust is both subtler and far more exciting – all of us information.  Our fat cells and our proteins; the glucose in our blood and the cholesterol in our cells.

The human body constantly remakes and regenerates information.  Information rich activities – like walking – generate more learning - and more effective bodies and brains.

For we learn or we die.  That’s especially true of immunity.  If we don’t adjust to our constantly mutating biological environment, we’re dust.

Evolution takes the long view.  For evolution, the species is more important than the individual.  That helped lead to sexual reproduction – to constantly remade and evolving sets of information that powers us into the future – and prepares for futures not yet imagined. The species must survive earthquakes and famines, wars and plagues.  So we’re built to survive. We learn time till the moment we die.  And the growth of that survival enhancing information can arrive just as powerfully from walking down the street than sitting and reading a text book.

Health is about how you live.  How you live determines the information system you constantly remake to let you carry on.

And thrive.  Regenerating every step of the way.

Whether you’re a jock or a nerd – information is what counts. Look at how you make those muscles – not just what they do.