The more literature I read about this, the more compelling I find this. In mammals, the larger the body the larger the brain. That's because you need all those neurons to control all those muscles. I recently read some papers that hypothesize the muscle atrophy we experience as we get older is partially the result of the neurons controlling those muscle-fibers dying [1]. As infants, our brains grow into our bodies by producing more neurons than we need and then killing off the neurons that aren't being used [2]. It makes sense to me that if we don't use our bodies in a variety of exercises, the lack of signal from the muscles to the brain could result in pruning those neurons as we get older.

[1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3868452/

[2] http://mxplx.com/meme/922/

As a potentially related point - in autistic individuals there is markedly less synaptic pruning:

http://www.cell.com/neuron/abstract/S0896-6273(14)00651-5?_r...

Does this mean you're saying you need _bigger_ muscles specifically to get bigger brains?

Is an elephant really more intelligent than a human then?

Nautilus has an article[1] that explores exactly this question. I beleive the conclusion was that it is the number of cortical neurons, not the total number of neurons and not brain mass that best predicts intelligence, or at least best correlates with our intuitive ranking of intelligence that puts humans and then primates at the top, above elephants.

[1] - http://nautil.us/issue/35/boundaries/the-paradox-of-the-elep...

No, an elephant needs a larger brain to run its larger body. Humans have enough brains to run our bodies, plus "extra" with which to think, in a manner of speaking.

https://en.wikipedia.org/wiki/Encephalization_quotient

I've always thought the metabolic needs must have been just as driving (specifically, being carnivores). Note: not a dig at vegetarians, we're talking about long before the proliferation of tofu and quinoa.

"A gram of brain tissue takes 20 times more energy to grow and maintain than a gram of tissue from the kidney, heart, or liver"

http://news.harvard.edu/gazette/story/2008/04/eating-meat-le...

I think he's not talking about intelligence, but about muscle control which kind of makes sense..

To what extent is that connectivity valuable beyond physical exercise? Is there good evidence that this does more than improve coordination and proprioception?

(Obviously coordination and proprioception are valuable, but people who value them likely don't need convincing of the merits of exercise!)

I think that _initially_ this new neural growth can be co-opted into general mental flexibility, particularly for things like mathematics and visual reasoning. In a sense, varied movement makes you more aware/perceptive of space. However, I think over time if you don't try to utilize your increased spatial awareness to solve spatial problems, eventually those new neurons will prune their synaptic connections to make the network as efficient as possible. Thus, I believe that pairing novel mental and physical training is the best bet for improving overall intellectual abilities.

Short answer: yes, physical exercise has been scientifically proven to improve cognition (working memory, attention, and other factors).

In addition to physical exercise, the two other things the author neglects to mention (though it might not be as relevant for her population, comprised of children) are diet and stress relief.

I used to do boxing earlier in college, and used to hit the gym religiously till last year, when my elbow fractured and got implants to hold it together. After that I wasn't able to do much activity, even if I wanted, apart from running. Even pushups carry a risk of screwing up the implants in my elbow.

What kind of physical activity do you think can be done in this type of scenario?

Maybe swimming? Possibly tennis or racquetball if you only use your other arm to hold the racquet. I'm not sure how easy it is to screw it up again, but if you can still handle running it seems like those two might be okay.

Pilates could be very useful. Most of it is very low impact strength training - instead of holding up your body weight, you're straining against springs, for example. There are a lot of exercises that don't focus on the arms because Pilates focuses on very discrete muscle groups for each exercise.

I wouldn't start with group classes, though: talk with your physical therapist (are you doing PT to help the recovery?) about appropriate exercises, and maybe sign up for a few introductory private pilates classes. Be sure to inform the instructor about the limitations you have.

It sounds like I have the same injury as you do. Five years ago I broke the olecranon in my left elbow and had to get it all screwed back together. To echo other suggestions, I would say swimming is definitely the way to go if you want to improve upper body fitness. Everything else I've found to be too high-impact and causes discomfort. Also keep up the running.

Some kind of casual low-impact sport (or at least low-bad-arm-impact), like pick-up soccer or disc golf. That way you'd still be getting the movement and coordination practice that you don't necessarily get from running. Also bicycling might give you the same benefits from running but with more new things to take in.

Swimming (try also cold water not pools). QiGong

Dance?

Biking!

Tai Chi

How would one get into 3D puzzles and simple machines/mechanics? I suppose IoT or Arduino could get you part of the way there but that's still very software-based.

You can buy puzzle cubes, they're made up of irregular blocks that need to be assembled in a certain way to hold together. The only downside to these is that after you "learn" how to put it together by assembling it a few times, it doesn't do much for you, though I suppose you could up the challenge by assembling it blindfolded.

Field stripping and reassembling guns is a good practical entry to mechanics. Again, after you've done it a few times it doesn't really teach you anything new, but the blindfold trick would work well here too.

Lego robots are another good basic intro into mechanical intelligence. You can graduate from them to DIY robotics kits.

What's a good example of a 3D puzzle?

Rubik's Cube. Try solving it yourself for a while (a few months/years). You will probably not completely solve it, but even solving one face, trying to solve a second one, trying to complete rings instead, etc, should get you to experiment and use new thinking models.

Juggling is also good for growth in both gray matter and white matter.

Why arent athletes the most intelligent then? Generally in society there is considered a negative correletion between people that exercise/play a ton of sports and intelligence. Whether this is true or not is up to debate, but stereotypes exist for a reason...

I think most professional athletes are highly intelligent, but some never learned to apply it to anything other than sport.

Watch Kobe or LeBron on the court. There is an incredible awareness of the shifting context of the game and the available moves. In the greatest athletes it is faster and more fluid than in most athletes.

It's a constantly shifting analytical mode that leans heavily on training and instinct, but is full of novelty. Consider that opponents spend weeks watching tape in hopes of understanding how to anticipate what Kobe will do.

In terms of physical metrics (size, speed, etc.) professional athletes are pretty close to average. I think it is a combination of intellect and general desire to win that makes some people become great athletes.

Because of what I like to call Cartesian Blindness (viewing the world through the mind/body duality) we assume it's simply a matter of great athletes having superior muscle fibers, etc.

Do you have a source for your statement that professional athletes are pretty close to average in "physical metrics"? By most accounts, there's been a recent Cambrian explosion in college and professional sports where larger pools of participants has resulted in a higher frequency of genetic outliers gravitating towards the sport for which their body is best suited.

David Epstein's "The Sports Gene" covers this topic with some depth.

Many people are brilliant, talented, and have a strong desire to win but lack the physical aptitude to support that at elite levels of play.

Aside from certain pathological cases (gymnasts need to be short and thin, offensive linemen need to be freaky massive), the difference genetics makes is pretty small in the grand scheme of things compared to proper training and mindset. Definitely less than 10% of total performance (with the exact number depending on the specific sport). Of course, at the very top, 10% is often a bigger margin than between first and last place.

grandalf speaks of team sports and situational awareness, complex planning, reading the floor, and other mental aspects of sports.

The examples in the "Sports Gene" are mostly about the kind of genetics that allow some to run micro to milliseconds faster than others, oxygenate slightly better, and so on. These things might help in the olympics where such minor distinctions matter but are certainly not a key or deciding factor in many sports.

While I completely agree about awareness being a form of intelligence, professional athletes (for the most part) are really on a different plane when it comes to physical metrics. An average person will never be able to attain a 4.4 40 for instance.

> An average person will never be able to attain a 4.4 40 for instance

Totally, true, but the number of people who are good at professional football is a very tiny subset of the people who can run a 4.4 40.

Athletes score very highly on specific measures of intelligence:

http://journals.plos.org/plosone/article?id=10.1371/journal....

http://discovermagazine.com/2010/apr/16-the-brain-athletes-a...

https://en.wikipedia.org/wiki/Theory_of_multiple_intelligenc...

While I don't think athletes are the most intelligent, I think the stereotypes of dumb jocks is simply a type of bias. If you were an athlete with potential, you would put more focus on your sport instead of academics. If you were bad at sports you would typically spend less time doing them which would then allow you to focus your time on other things like academia. In America, when all you need to do to get As in like highschool is to put effort, the ones who weren't great in sports tend to get higher grades which is perceived as having a higher intelligence. Thinking that athleticism is negatively correlated to intelligence is just ignorant.

Athletes aren't exactly a random sample. They are people who have self-selected to spend time on athletics.

I also don't think the stereotype is accurate. We tend to confuse interest in pursuits that are perceived as intellectual with actual intelligence.

It takes a lot of hard work to be exceptional at symbolic manipulation/"smart". It also takes a lot of hard work to be an exceptional athlete. Unfortunately, there is only so much time in a day.

You might be surprised to learn that there is a negative correlation between obesity and IQ.

It depends on the sport. Check the average GPA for any top level university gymnastics team. It needs to be a sport that invokes complex coordination of a wide variety of muscle groups.

The basic idea is that while you are learning to do challenging gymnastic (or other physical) skills, the brain is releasing growth hormones to learn the skill. But they aren't targeted. It's hard to grow the part of the brain that does a cartwheel on a balance beam without also growing the part of the brain that does calculus.