Over the course of the past nine episodes, we've covered the topics that you'd expect to fall under the umbrella of this show's “study skills” subtitle –

preparing for tests, planning, beating procrastination, and so on.

Today we're going to step slightly out of that umbrella's shadow to talk about exercise.

But don't be fooled – this video will still help you to become a better student.

Exercise is crucial for keeping both your body and your brain healthy, and as you'll see later in this video,

it's also a simple way to improve your ability to learn and focus.

The problem is that our culture is becoming less and less active.

Here in the U.S., nearly a third of kids between the ages of 2 and 19 qualifies as either overweight or obese.

And on average, we spend over 10 hours a day looking at screens – an activity that almost always involves sitting down.

And many schools aren't helping the issue, as physical education programs are constantly being cut in favor of adding more time to other classes –

even though, as you'll see in a minute, there is evidence to show that the opposite tactic would produce better academic results.

So today we're going to dive deep into the brain benefits of exercise.

And keep in mind here that we're not talking about a narrow definition of exercise, like lifting weights or running.

Exercise comes in many different shapes and forms, and regardless of your skill level or physical limitations, you can probably find something that gets your heart rate up

– which can, in turn, improve your mind.

[Theme Music]

When we think about the concept of “learning”, we often picture someone lost in some kind of intellectual work –

doing research, reading a book, or maybe working through a bunch of math problems.

But it's important to realize that all of these activities are relatively recent inventions when looked at on an evolutionary time scale.

Let's go to the Thought Bubble.

For the vast majority of the time that the brain has been around –

be it inside the skull of a human or something else – its ability to learn evolved right alongside movement.

And this makes sense if you think about it.

Lifeforms that don't need to move really have no use for a brain.

Plants just need to take root in one spot and then grow upward, and for that, a fixed set of genetic programming will do just fine.

The ability to learn, think, and strategize only becomes necessary when you can move around,

because now you need to be able to navigate a complex environment, find food and remember its location later on, and escape from predators.

If you want a good example of this difference, look at the sea squirt.

These invertebrates start their lives in a larval stage complete with a primitive eye,

a tail-like nerve cord that lets them move around, and a brain.

At this stage, their goal is to find a spot on the ocean floor where they can attach themselves.

Once they do this, that's where they'll be staying for the rest of their lives.

And to seal the deal, they absorb all of those useful features that let them move around

– the eye, the nerve cord, and – you guessed it – the brain.

That's right – once a sea squirt doesn't need to move anymore, it basically eats its own brain.

Thanks, Thought Bubble – I think?

The neuroscientist Rodolfo Llinás used the case of the brain-eating sea squirt in his book I of the Vortex: From Neurons to Self in order to illustrate his conclusion that:

“That which we call thinking is the evolutionary internalization of movement.”

In other words, brains are for creatures that move.

Once you stop using it, you lose it.

In fact, “use it or lose it,” is a principle that applies to much of biology – not just brains.

That's why your muscles can start to atrophy if you don't use them for long enough,

and why failing to stay active and learn new things can greatly increase the risk of developing dementia as you get older.

To use an even more extreme example, astronauts that spend a lot of time in orbit often suffer from a condition called spaceflight osteopenia,

which is a loss in bone density that happens because the skeleton doesn't have to constantly fight against the pull of Earth's gravity.

On the whole, every part of your body is adapted to allow you to do specific things.

If you aren't doing them, then those parts of your body simply become resource hogs.

But you can't just decide you don't need them and turn them off –

your body's systems are highly connected and they depend on each other,

which means that you need to do what your body is built to do if you want to keep it all working.

And in the case of exercise, it's not just a matter of “working” or “not working”

– in addition to keeping you healthy, getting your heartbeat elevated on a regular basis can also make you a better student.

Just look at the school district of Naperville, Illinois.

Back in the year 1990, a P.E. teacher in Naperville named Phil Lawler decided that the traditional structure of P.E. classes just wasn't going to cut it anymore.

Since they were almost always based on sports, the few kids who were already athletic would

naturally dominate the more active roles, and by consequence, lots of other kids would end up just standing around – not really doing much at all.

Lawler decided to change things up, and he shifted his class's focus from traditional sports to more fitness-based activities like jogging.

He placed an emphasis on constant movement and keeping heart rates in an elevated zone during the entire period.

And – most importantly – he graded his students on effort rather than skill.

By using heart rate monitors, he was able to tell that students who clocked 10 minute mile times were still working just as hard as those who could finish in 8.

He called this program Zero Hour P.E., and it started as an optional morning program before becoming integrated into the school's normal schedule.

By the end of its first semester in 1990, his test group of students showed a 17% improvement in reading and comprehension,

compared to a 10.7% average improvement for the kids who didn't participate.

After that, the structure of Zero Hour P.E. became the archetype for the entire district's physical education program.

And today, the district consistently ranks in the state's top 10 academic performers,

even though money spent per student there is much lower than other top-tier districts.

The correlation between fitness-based P.E. classes and higher grades isn't limited to Naperville, either.

After studying Lawler's program, another P.E. teacher named Tim McCord brought it to his own school district in Titusville, Pennsylvania.

And in 2008, eight years after the program had started there, the district's reading scores had gone from below the state average to 17% above it.

Likewise, math scores went from below the average to 18% above it.

So what's going on here?

How exactly does exercise help you become a better student?

Well, broadly speaking, regular exercise improves your brain in three important ways.

First, it optimizes the levels of neurotransmitters like serotonin, norepinephrine, and dopamine.

These are all crucial for learning.

Keep in mind that we are hugely oversimplifying things here, but in general, serotonin helps to regulate your mood and keeps you happy.

Norepinephrine amplifies signals related to attention and motivation,

and dopamine is highly involved in learning, movement, and operating the brain's reward center.

Regular exercise balances these neurotransmitters, along with lots of others that are equally important for keeping your brain healthy.

Secondly, exercise can also stimulate neurogenesis, which is the birth of new neurons from neural stem cells in the hippocampus.

This was once thought to be impossible.

For a long time, the prevailing belief in the scientific community was that you were born with all the neurons you were ever going to get.

But we now know that new neurons are created even during adulthood, and exercise increases their rate of creation.

Now, one important thing to note here is that these new neurons are born as stem cells that don't have an immediate purpose.

As a result, many of them die – again, “use it or lose it.”

In order for a new neuron to survive, it has to get plugged into an existing neural network, and that happens when you learn new things.

So really, the crucial combo for this particular bit of brain optimization is regular exercise AND constant learning.

Now if you're a student, you've probably got the second part down pat at the moment,

but I do want to mention this, since it remains true even as you get older and eventually don't have to go to school anymore.

Lastly, exercise improves the ability of neurons to bind to one another, which is how new neural pathways are formed and how memories take hold.

It does this by promoting the production of a protein called brain-derived neurotrophic factor (or BDNF),

which in turn enables and improves a process called long-term potentiation.

This is the mechanism that enables learning.

When new information enters your brain, neurons start firing using existing stores of another neurotransmitter called glutamate.

If the firing continues, each active neuron will also start generating building material for the creation of brand new synapses,

which are connections between separate neurons.

As these new synapses are created, memories form.

And BDNF is the secret sauce that makes the whole process possible.

In fact, researchers have discovered that depriving rats of BDNF causes them to lose the capacity for long-term potentiation.

And, on the flip side, they've also found that injecting BDNF directly into a rat's brain increases that capacity.

Now, this does not mean that you should go ask your doctor to inject BDNF in your brain – they're probably gonna give you a pretty weird look.

And it's unnecessary anyway, because your brain naturally produces more BDNF when you learn new things and when you exercise.

There are also other benefits that go beyond learning;

research has found that regular exercise can also improve your ability to focus and block out distractions,

it reduces stress, and it lets you control the weather with your mind.

We don't have time to dig into the details of these benefits here, but if you're curious,

you can learn a lot more about each of them in Dr. John Ratey's book Spark: The Revolutionary New Science of Exercise and the Brain.

Except for that last one – I was lying about that one.

What we need to do now is answer the million-dollar question: How, exactly, should you exercise if you want to improve your brain's performance?

Well, first off, don't try to do traditional academic learning during intense exercise.

You think it'd be a pretty sweet productivity hack to study your organic chemistry flash cards during a set of heavy deadlifts, but it's not going to work out so well.

When your heart rate is elevated, blood actually moves away from your prefrontal cortex,

which manages your executive functions, working memory, and the intake of new information.

However, that blood comes back almost immediately after you finish exercising, so doing a workout or going for a run right before you start learning is a great idea.

As for how you should exercise – well, that's mostly up to you, but you'll get the best results by combining an elevated heart rate with complex, skill-based movement.

One way to do this is to opt for a sport or a skill-based activity that combines both,

like figure skating, basketball, skateboarding, martial arts, or even intense yoga.

Alternatively, you can first do some aerobic exercise followed by a lower intensity bout of skill based movement, like going for a 15 minute run and then doing some rock climbing.

But beyond all else, just get started.

Even going for a short walk once a day can have a lot of benefits.

So if you're not getting a lot of exercise right now, just start small, do what you can do, and focus on building the habit.

You don't need to worry about finding the perfect workout routine, or memorizing all the details we covered about BDNF and neurons.

If you can just build that habit, your brain will take care of the rest for you.

Over the course of this series we've covered tips and strategies for dealing with many of the biggest challenges you'll face as a student,

and we've done our best to use research and our own personal experiences to make those tips as useful as we possibly could.

But as you dive into your work, you're gonna discover other strategies that might be even more effective,

or you'll make tweaks that suit your style of working better than anything we could come up with.

And I'd encourage you to actively seek out these improvements, as learning and productivity are two fields where there's no single set of “best” practices.

As Bruce Lee once said, “Adapt what is useful, reject what is useless, and add what is specifically your own.”

And just as Lee himself strove to make this cycle of self-improvement a lifelong process, so should you.

We've covered a lot of ground over the past 10 episodes, but there's always more to learn – both in the realm of study skills and beyond.

So keep learning, keep improving, and don't forget to be awesome.

Crash Course Study Skills is filmed in The Dr. Cheryl C. Kinney Crash Course Studio right here in Missoula, MT, and its made with the help of all these nice people.

If you'd like to keep Crash Course free for everyone, forever, you can support the series over at Patreon, a crowdfunding platform that allows you to support the content you love.

Thank you so much for your support.