inside your body there are three command systems
and meditation rewrites all of them at once
there was a comment that got me really excited
one viewer said
he wanted to hear about the brain nervous system
the autonomic nervous system and the endocrine system these three
integrated with Buddhist practice
when I saw this comment I thought
this is exactly what I have always wanted to talk about
but never found the right way into
because most scientific research looks at them separately
one group studies the brain
another group studies the autonomic nerves
and yet another group studies hormones
but your body is not divided into departments
your body is one whole
and twenty five hundred years ago a group of people
without any instruments at all
designed a set of practices
that happen to act on all three systems at once
today I am going to break this down
hello
everyone
I am Wang Lijie
first let me draw you a map
inside your body there are three command systems
each has its own headquarters its own communication network
its own operating logic
but they are deeply intertwined
the first one
the central nervous system
that is your brain and spinal cord
it handles everything you are consciously aware of
thinking deciding perceiving speaking
it communicates with electrical signals
extremely fast
responses in milliseconds
you see a ball flying toward you
and within a fraction of a second you decide to dodge or catch it
the second one
the autonomic nervous system
also known as the involuntary nervous system
it is not under your conscious control
it runs your heartbeat breathing digestion blood pressure body temperature
all the things that keep you alive without you thinking about them
it splits into two forces
the sympathetic nerves are the gas pedal
responsible for fight or flight
speeding up your heart dilating your pupils sending all resources to the front line
the parasympathetic nerves are the brake
responsible for rest and repair
slowing the heart restoring digestion bringing the immune system back online
the third one
the endocrine system
it regulates your body through hormones
cortisol adrenaline serotonin dopamine oxytocin
these chemical messengers travel through the bloodstream
much slower than electrical signals
but their effects last much longer
a single release of cortisol can affect you for hours
a shift in your endocrine pattern can take weeks to complete
three systems
three signal speeds
three time scales
electrical signals are lightning at the millisecond scale
neurotransmitters are couriers at the second scale
hormones are slow mail at the scale of hours to days
but these three systems do not operate on their own
they share a common hub
called the hypothalamus
the hypothalamus is only the size of an almond
but it may be the most underrated organ in your body
because it is at once a neural structure an endocrine gland
and the top command center of the autonomic nervous system
you can think of it as a joint command of all three forces
the cerebral cortex is the general staff
in charge of high level strategy
the autonomic nerves are the automated frontline troops
handling routine situations without waiting for orders
the endocrine system is the supply line
in charge of long term resource allocation
the hypothalamus sits in the middle
gathering translating and distributing information from all three
alright
remember this map
next I am going to tell you something really fascinating
modern science has found
there is one human activity
that can change the operating state of all three systems at once
not drugs
not surgery
not gene editing
it is meditation
let us go through them one by one
first the central nervous system
I have covered this in detail in a previous episode
today let me recap the key conclusion in one sentence
when you meditate
activity in the brain default mode network drops significantly
the default mode network is that voice in your head that keeps telling stories
who am I my past my future what others think of me
when this voice quiets down
the functional connectivity between the salience network and the executive control network actually strengthens
in plain language
your brain shifts from the autopilot narrative mode
to the manual awareness mode
a comprehensive functional connectivity study in 2022 found
mindfulness meditation significantly strengthened the connection between the anterior cingulate cortex and the insula
the anterior cingulate cortex handles conflict monitoring and attention allocation
the insula handles interoception
which is the awareness of your internal bodily states
what does stronger connection between these two regions mean
it means meditation is training your brain
to monitor what is happening in your body more accurately
instead of being lost in stories about yourself
did you notice
the insula is a crucial region
it is not just a brain area that processes information
it is your brain window into the body
you can feel your heart racing your stomach churning your face burning
all thanks to the insula at work
meditation strengthens the function of the insula
which means you become more aware of your body state
and this capacity for awareness
is exactly the key that connects the first system to the other two
this is the first layer of change
but if there were only this layer
meditation would just be a form of attention training
no different in essence from doing math problems
what truly makes meditation different
is the next two layers
the second system
the autonomic nervous system
this is the main event today
modern people share a common problem
the sympathetic nerves are chronically overactivated
you are not being chased by a tiger
but your work stress social anxiety and the negative news you scroll on your phone
are no different from a tiger to your autonomic nerves
your gas pedal is always pressed down
the brake never gets used
over the long run
cardiovascular disease weakened immunity chronic inflammation digestive disorders
they all come
here I have to give a grand introduction to one character
the vagus nerve
the vagus nerve is the most important nerve in the parasympathetic nervous system
and the longest cranial nerve in your body
it starts from the brainstem
and winds all the way down
connecting the heart lungs stomach and intestines
reaching almost every internal organ
its name in Latin means the wanderer
because it wanders everywhere inside your body
the vagus nerve is your body peace envoy
when it is activated
the heart slows down
breathing deepens
digestion recovers
inflammation levels drop
immune function strengthens
the activity of the vagus nerve has a precise quantifiable measure
called heart rate variability
pay attention
heart rate variability is not about how fast your heart beats
but about how much the intervals between your heartbeats vary
a healthy heart does not beat as precisely as a metronome
but has tiny irregular fluctuations between each beat
the greater this fluctuation
the more active your parasympathetic nerves are
the more flexible and resilient your body is
low heart rate variability
means your autonomic nervous system has become rigid
the gas pedal has seized the steering wheel
so what does meditation do to the vagus nerve and the autonomic nerves
a randomized controlled trial in 2022 found
just ten days of online mindfulness training
significantly raised the participants heart rate variability
not only during the day
but at night as well
higher nighttime heart rate variability means sleep quality improved
because the parasympathetic nerves should dominate at night
if they are not strong enough
your sleep is shallow and unrestorative
another study that same year used electrocardiography
to precisely measure autonomic changes during meditation
the results were very clear
parasympathetic activity strengthened significantly
sympathetic activity dropped significantly
the gas pedal eased off
the brake came on
but here is a key question
how do you activate a system you cannot control
the reason it is called autonomic
is that it does not obey your conscious command
you cannot stop your heart with your mind
nor can you order your stomach to stop moving
the answer is hidden in the breath
breathing is an extremely special function in your body
because it is controlled by both the autonomic and the voluntary nervous systems
when you are not thinking about it it breathes on its own
when you want to control it you can
it is the only two way bridge connecting the conscious and the unconscious
a large scale meta analysis in 2022
pooled data from two hundred and twenty three studies
the conclusion was very clear
slow voluntary breathing
can significantly raise vagally mediated heart rate variability
effective during the breathing exercise
effective after a single session
and even more effective after long term practice
Buddhism calls this anapana
observing the breath
twenty five hundred years ago there was no concept of heart rate variability
but the Buddha observed that the breath is the entrance into the body automatic system
through this bridge
your active awareness can influence systems you normally cannot control
translated into modern terms
you use the voluntary nerves to control the rhythm of your breathing
this change in rhythm directly regulates the tone of the vagus nerve
which shifts the balance of the whole autonomic nervous system
think about it
what an exquisite design this is
you cannot directly order your heart to slow down
but by controlling your breath
you can indirectly pluck the string of the vagus nerve
and change the tone of the whole autonomic nervous system
the Buddha did not know the vagus nerve existed
but he found a way to operate it
and it is not just observing the breath
many practice traditions also have mantra recitation and chanting the Buddha name
have you ever wondered why you chant out loud
the vibration of the vocal cords can physically stimulate the vagus nerve directly
because the vagus nerve has a branch running right along the vocal cords and throat
when you chant om mani padme hum
that low frequency resonance is not just making sound
it is massaging your vagus nerve
this is not a metaphor
this is anatomy
alright
now for the third system
the endocrine system
when you feel continuous stress
your body activates a signaling chain
called the hypothalamic pituitary adrenal axis
the HPA axis for short
I introduced it in the episode on spontaneous remission
let me recap briefly
the hypothalamus sends a signal
to the pituitary gland
the pituitary passes it to the adrenal glands
the adrenal glands release cortisol
cortisol is your stress hormone
in the short term it helps you focus and handle emergencies
but if it stays high for a long time
immunity is suppressed
the hippocampus is damaged
memory declines
chronic inflammation rises
emotional regulation breaks down
the problem for modern people is
the HPA axis stays activated for the long term
because your stressors do not come and go like wild beasts
your mortgage your KPIs
your social comparisons your anxiety about the future
these stressors are constant pervasive and never disappearing
your HPA axis is always working overtime
what does meditation do to this system
a randomized controlled trial in 2020 found
after eight weeks of transcendental meditation practice
young people salivary cortisol on waking dropped significantly
and the cortisol spike after waking also shrank
what does this mean
it means meditation works not only during the tens of minutes you sit
it is changing the baseline setting of your HPA axis
the factory default of your stress system is turned down
another study in 2019 was even more precise
they developed an approach grounded in a psychoneuroendocrine immunology framework
a meditation method
after thirty hours of training
the participants in a resting state
and under acute stress showed salivary cortisol levels
that both dropped significantly
in other words
not only did your resting stress level go down
but the intensity of your reaction to sudden stress went down too
your entire stress response system became gentler
here is a detail that is easy to overlook
there is a direct highway between the autonomic nervous system and the endocrine system
the vagus nerve not only regulates heartbeat and breathing
it also connects directly to the gut
trillions of microbes live in your gut
they communicate with the brain through the vagus nerve
this is called the gut brain axis
even more astonishing
ninety five percent of the serotonin in your body is not made in the brain
but in the gut
serotonin is a key neurotransmitter that regulates mood
when meditation activates the vagus nerve
it not only changes your heart rhythm
it also affects the microecology of your gut and the synthesis of serotonin
the interplay between the second system and the third system
is far tighter than we imagine
but the story of the endocrine system is not only about cortisol
there is a deeper layer here
altruistic behavior and prosocial motivation
activate a completely different endocrine pathway
the oxytocin and serotonin pathway
I broke down this mechanism in detail in the episode on dedication of merit
altruistic intention is not a moral performance
physiologically it takes your body
from a cortisol dominated threat mode
to an oxytocin dominated connection mode
and almost every practice in Mahayana Buddhism
has an altruistic framework
compassion bodhicitta dedication of merit
this is not a moral requirement
this is an endocrine prescription
alright
we have gone through all three systems
now do one thing with me
look at these three layers stacked together
the changes in the central nervous system happen at the millisecond to second scale
you close your eyes and start observing the breath
within a few minutes the default mode network activity begins to drop
the changes in the autonomic nervous system happen at the minute to hour scale
after a single meditation session
your heart rate variability improvement can last for hours
after a few weeks of practice a new baseline starts to form
the changes in the endocrine system happen at the day to week scale
resetting the baseline of the HPA axis takes weeks or even months of sustained practice
three speeds
three scales
happening at once
you think you are just sitting there doing nothing
your body disagrees
and Buddhism
without any of these scientific concepts
designed a system of practice
that precisely corresponds to these three layers
shamatha and vipassana
correspond to the central nervous system
shamatha quiets the default mode network
vipassana strengthens the function of the salience network and the interoceptive network
anapana and mantra recitation
correspond to the autonomic nervous system
activating the vagus nerve through breath and sound vibration
switching from sympathetic dominance to parasympathetic dominance
precepts and vows
correspond to the endocrine system
precepts reduce the behavior patterns that keep activating the HPA axis
greed hatred and delusion are not abstract moral concepts
they are the three sources of chronic stress
greed is the compulsive chasing of reward
which throws the dopamine system off balance
hatred is the overreaction to threat
which keeps cortisol high
delusion is ignorance of the whole mechanism
so you have no idea what your body is going through
making vows sets an altruistic framework of intention
shifting the endocrine keynote from cortisol to oxytocin
you see
the Buddhist system of practice is not a pile of scattered rituals and rules
when you look at it through the three system framework
you find it is a precise whole body tuning program
different practice methods target different system layers
different time scales require different intensities of practice
and the well worn advice to practice consistently
has a very concrete reason at the physiological level
because the slowest system needs the longest time to respond
here I have to say something honest
current scientific research cannot yet
precisely track within a single experiment
the real time linked changes of these three systems during meditation
most studies look at only one or two of these measures
what I have done today is piece together the conclusions of several independent studies
to build an integrated picture
I am very confident about the big direction
but the detailed causal chains and the precise interaction mechanisms among the three systems
still need more interdisciplinary research to verify
but this is exactly what moves me most
science is divided into disciplines
it cuts the body into pieces to study
neuroscience handles the brain
endocrinology handles hormones
autonomic nerve research sits in yet another discipline
but the body is not divided into departments
your brain state affects your autonomic nerves
your autonomic nerves affect your hormone levels
and your hormone levels in turn affect your brain state
this is a closed loop
there is no first or second here
and what the Buddha did twenty five hundred years ago
was to observe this closed loop without dividing it into departments
he did not cut his experience into
this is the brain this is the nerves this is the hormones
he directly observed the operating pattern of the whole system
and then designed a practice
that tunes all three layers at once
maybe this is why
meditation cannot be reduced to any single scientific explanation
its effect is itself cross system multi scale and simultaneous
trying to explain meditation with a single mechanism
is like trying to explain a symphony with a single note
and the Buddha did it
with the single method of vipassana
he heard the whole piece of music
finally I want to leave you with a question
if there really are three command systems in your body
and you have only ever used the first one
the central nervous system you are conscious of to make decisions
then by what rules have the other two systems been running all along
who has been giving them orders
is it you
or your habits your fears your evolutionary instincts
the essence of practice
could it be reclaiming the right to know and regulate the other two systems
what do you think
which of these three systems do you most want to explore deeper
should the next episode break down the autonomic nerves and the vagus nerve on their own
or dig into the relationship between the endocrine system and emotions
tell me in the comments
I am Wang Lijie
see you next episode