We all know that exercise is good for your body
and your brain, but why?
In fact, exercise decreases depression and anxiety.
How and what kind of exercise does that?
That's what I'm talking about today.
I'm Dr. Tracey Marks, a Psychiatrist
and I make mental health education videos.
You've probably heard the term runner's high,
which describes a phenomenon
where after intense aerobic exercise, like running,
you can experience this euphoric feeling
and sense of wellbeing.
For years, it was hypothesized
that this was due to the release of endorphins,
which is your body's natural opiate.
Well, it turns out the runner's high
really isn't that common among runners,
but anyone can experience a relaxed feeling
after moderately intense exercise, not from endorphins,
but from endocannabinoids.
Let me explain.
You do get endorphin release with exercise,
it serves the purpose of lessening pain perception
during an after intense activity.
But those endorphins don't affect your brain
and therefore your mood because they don't make it across
the blood brain barrier.
Your brain is very selective about what that allows
to pass through the gate.
Some molecules can pass and then others not.
An example of this is with the anti-histamine medications.
Histamine is a chemical in your brain
that makes you alert in medications that block it,
make you sleepy.
Histamine in your body from the neck down
causes the allergic response of itching,
hives, airway constriction.
So, below the neck,
anti-histamines block this allergic reaction.
Some anti-histamines like Benadryl make you sleepy
because it crosses the blood brain barrier
and affects the histamine receptors in your brain.
Anti-histamines that don't make you sleepy,
like Zyrtec were manufactured to be able to not make it
to the brain.
So back to exercise, we now believe that the good feeling
you get after exercise is due to the release
of endocannabinoids that do cross the blood-brain barrier.
Endocannabinoids are substances that your body produces
that activate cannabinoid receptors in your body.
The two most studied endocannabinoids are AEA and 2-AG.
I'll spare you the full names,
but the A stands for arachidonic acid.
When something is made in the body,
it's called an endogenous source.
When the source is outside of your body,
it's called exogenous.
The two most studied exogenous cannabinoids
are THC and CBD from the cannabis plant.
Cannabis has over a hundred cannabinoids
that affect the cannabinoid receptors in your body.
But THC and CBD are the two that we know the most about.
So you can think of vigorous exercise
as making your own strain of cannabis, sort of.
Your homemade cannabinoids have a mood lifting
and anxiety reducing effect, but it gets better.
Regular exercise has a longer effect on improving mood
and anxiety because it triggers brain derived
neurotropic factor, which causes neurogenesis.
Neurogenesis is the growth of new cells
and the regeneration of damaged cells.
Also, researchers have seen
that people who exercise regularly
have bigger hippocampuses because of this neurogenesis.
In the brain world, you want to have a big hippocampus.
A small hippocampus is considered a hallmark of depression.
Your hippocampus is located in your temporal lobe
and it's associated with memory and learning.
It not only controls learning tasks like problem solving,
but controls your ability to process emotion
and allows you to level up your psychological insight.
Researchers also believe with neurogenesis,
that there's a downstream effect of increasing dopamine
and serotonin, both of which we know improves mood.
What kind of exercise can give you
this nice big hippocampus?
The Centers for Disease Control and Prevention
and other sources recommend 150 minutes a week
of moderate intensity exercise
or 75 minutes a week of vigorous intensity.
With moderate intensity, you can talk, but not very easily.
And you can't sing because your breathing is too fast
to hold notes.
So if you're talking, you're huffing.
Examples of moderate exercise are brisk walking
around three miles per hour, slow biking, dancing,
or doubles tennis.
So if you're walking your dog or gardening
and you can sing or whistle attune,
you're not doing it hard enough.
With vigorous intensity, you can't talk
because you're breathing too hard.
Examples of this are running,
jogging at around six miles per hour,
which would be a 10 minute mile,
swimming laps, or some aerobic classes,
depending on how hard they have you working.
You can divide up these times however you want,
but it's best to spread it out over the week,
like 30 minutes on a treadmill,
five times a week for moderate exercise,
or a 15 minute fast bike ride five times a week.
Now, I will say any kind of activity
is better than no activity.
So, a slow walk in your neighborhood
still brings you some benefit,
but to activate the Endocannabinoid System
and increase neurogenesis, you need some aerobic activity.
I have a link in the description that will give you
more guidelines on physical activity.
It's from the Department of Health and Human Services.
If you like this video, take a look at this one
on how intermittent fasting also changes your brain wiring.
Thanks for watching.
See you next time.