Science of understanding life

What autonomic nervous system Controls?

Science of understanding life

(Body, Medicine, Science and Living)

Episode 1

What the Autonomic Nervous System Controls? (What autonomic nervous system Controls?)

When Medical Tests Are Normal but Your Body Isn’t...

Have you ever been told that nothing is wrong - yet your body refuses to feel okay?

We usually think of our bodies as something we consciously control. We raise an arm, take a step, speak a word - actions driven by intention. But when you pause and think about it, there are countless processes that continue without any conscious effort.
The heart keeps beating through the night. Breathing goes on even while we sleep. Body temperature stays stable as the seasons change. Food is digested, wounds heal, all on their own.
The system that quietly coordinates all of this is the autonomic nervous system.
As its name suggests, the autonomic nervous system regulates itself. It operates independently of our will and manages the body’s most essential functions for survival. Heart rate, blood pressure, breathing, temperature regulation, digestion, hormone secretion, even immune responses - its reach is broader than most of us realize. When we feel tense and our heart races, or when we relax and our breathing deepens, these are all responses governed by the autonomic nervous system. In other words, it constantly monitors the body’s condition and adjusts the internal environment accordingly. It is the body’s silent manager.
This system is divided into two main branches: the sympathetic and the parasympathetic nervous systems. The sympathetic nervous system prepares the body for action. When danger is perceived, it speeds up the heart, directs blood to the muscles, and mobilizes energy for immediate survival. The parasympathetic nervous system, on the other hand, is responsible for recovery. It slows the heart rate, supports digestion, and allows the body to rest. These two systems work in opposite directions, but neither is inherently good or bad. What matters is balance.
The problem is that modern life constantly pushes us toward sympathetic dominance. We live under time pressure, work in a state of chronic tension, and remain stimulated until the moment we fall asleep. The body begins to mistake everyday life for a continuous emergency, losing opportunities to enter recovery mode. And then what happens? Sleep becomes shallow, digestion weakens, unexplained fatigue and pain accumulate. Medical tests show nothing abnormal, yet the body feels persistently unwel - an experience many people know all too well.
The autonomic nervous system is invisible, but it is connected to nearly every symptom we experience. Dizziness, palpitations, tingling in the hands and feet, chronic fatigue, pain without a clear cause - often these are not problems of a single body part, but signs of a disrupted regulatory system. Understanding the autonomic nervous system changes how we view symptoms. Instead of asking, “What’s broken?” we begin to ask, “What state is my body in right now?”
Throughout this series, the autonomic nervous system will continue to appear. That’s because it is one of the most fundamental keys to understanding the body. Our bodies are always sending us signals. We simply don’t know how to read the language. Once we begin to understand the autonomic nervous system, those signals slowly start to make sense. And from that point on, the way we relate to our bodies begins to change.
When you understand this, you truly start to use your body differently.
In the next episode, we’ll begin to listen more closely to those signals.

The Autonomic Nervous System is an Invisible Conductor.

The autonomic nervous system has always been there, yet for a long time we treated it as something too natural to question.
Breathing happens. The heart beats. Body temperature is regulated. Digestion proceeds.
Because this intricate system operates without our conscious awareness, it was paradoxically pushed to the margins of scientific inquiry.
Medicine is a science.
It is the science of understanding the human body - but it has also tended to privilege what can be seen, measured, and structurally confirmed. A single nerve, a muscle, an organ could be clearly identified and explained. But the system that orchestrates all of them was often dismissed with the assumption, “That’s just how it works.”
The autonomic nervous system existed more as a background condition than as a target of treatment.
When something went wrong, symptoms appeared, and medicine followed the symptoms. Yet there was no clear language to explain where those symptoms truly originated, or why they manifested across the entire body in such varied forms.
That paradigm began to shift with COVID-19.
After infection with COVID - 19, many patients developed symptoms that defied easy explanation:
extreme fatigue, palpitations, shortness of breath, dizziness, digestive disturbances, impaired temperature regulation, anxiety, even states resembling panic. Diagnostic tests often came back normal, or the symptoms did not fit established disease categories. And yet, the body was undeniably different from before.
These lingering aftereffects, later termed Long COVID, shared a common denominator: dysfunction of the autonomic nervous system.
Whether through direct viral effects or indirect immune and inflammatory responses, the body’s regulatory system had been disrupted, leading to a collapse of physiological balance as a whole.
The autonomic nervous system is invisible.
But it quietly governs nearly every function of the body. Through the delicate balance between the sympathetic and parasympathetic systems, we tense and relax, act and recover. When this balance is lost, it is not a single organ that feels unwell—the entire body begins to feel unfamiliar.
For this reason, disorders of the autonomic nervous system have long been misunderstood.
They were easily reduced to phrases like “it’s psychological,” “it’s just stress,” or “there’s nothing wrong on the tests.” After COVID-19, however, medicine could no longer afford to ignore this domain. On a global scale, we witnessed how profoundly human life is shaken when an invisible regulatory system breaks down.
The task before us is now clear.
We must stop treating the autonomic nervous system as a secondary concept and begin to recognize it as an independent field of study and a central axis of treatment. This requires a shift in perspective - from viewing the body as a collection of parts to understanding it as a continuously coordinated whole.
The autonomic nervous system works in silence.
But when that silence is disrupted, its importance becomes unmistakable. Perhaps COVID-19 was the moment humanity was finally forced to listen - to the invisible conductor it had long taken for granted.

The Autonomic Nervous System: A Peculiar Network

The autonomic nervous system is a peculiar kind of nervous system.
Unlike the brain or spinal cord, it does not present itself as a clearly visible structure. Nor is it easily recognized as a distinct, thick bundle of nerves like the spinal nerves. For this reason, we have often treated the autonomic nervous system as something vague or abstract. Yet invisibility does not mean nonexistence.
The autonomic nervous system does, in fact, have a definite anatomical basis.
Centrally, its regulatory centers reside in the brainstem, the hypothalamus, and the spinal cord. Within the spinal cord itself are the cell bodies of sympathetic and parasympathetic neurons, whose signals descend along the spine and are transmitted throughout the body.
In the periphery, the autonomic nervous system does not exist as a single, independent nerve.
Rather, it appears as a dense network intricately interwoven with blood vessels, organs, the endocrine system, and the immune system. Its signals reach the heart, lungs, gastrointestinal tract, bladder, vascular walls, sweat glands, and pupils - virtually every physiological function that operates beyond conscious awareness.
This is precisely where the difficulty lies.
The autonomic nervous system is hard to point to and say, “It is here,” and equally difficult to visualize and declare, “This is where it is damaged.” As a result, medicine struggled for a long time to treat it as a clearly defined object of diagnosis and therapy.
Approaching it was challenging for another reason as well.
The autonomic nervous system is not a problem of a single organ, but a problem of regulation. A racing heart may reflect a primary cardiac issue - but it may just as well be the result of disrupted autonomic balance. Symptoms such as digestive disturbances, chronic fatigue, dizziness, anxiety, and temperature dysregulation span the entire body. They resist confinement to a single medical specialty and often fail to register clearly in laboratory tests.
Consequently, treatment has often fragmented around symptoms.
Heart symptoms were sent to cardiology, gastrointestinal complaints to gastroenterology, anxiety to psychiatry. Yet from the perspective of the autonomic nervous system, all of these manifestations can be understood along a single axis: the breakdown of the regulatory system that maintains bodily homeostasis.
Since COVID-19, this understanding has shifted rapidly.
The wide range of persistent post-infectious symptoms - now known as Long COVID - could not be adequately explained by organ-centered medicine. At this point, global attention turned toward autonomic nervous system dysfunction, or dysautonomia. Whether through direct viral effects, inflammatory responses, or immune dysregulation, the autonomic nervous system was affected, and the body’s overall rhythm began to collapse.
As a result, approaches to the autonomic nervous system are evolving.
Treatment is moving away from reliance on a single medication or procedure and toward layered, integrative strategies. Breathing and sleep, posture and movement, stress regulation, retraining of the nervous system, and, when necessary, pharmacological interventions—all are considered. Because the autonomic nervous system is deeply intertwined with daily life, treatment inevitably involves restructuring life itself.
Social awareness has also grown noticeably.
After COVID-19, the number of people who were “unwell despite normal test results” increased dramatically. Their experiences could no longer be dismissed as mere sensitivity or psychological weakness. Beyond clinical medicine, fields such as rehabilitation, physical therapy, exercise science, psychiatry, and psychosomatic medicine have begun to adopt the autonomic nervous system as a shared conceptual framework.
The autonomic nervous system remains difficult to see.
But we now understand that its invisibility does not reflect insignificance. It was overlooked precisely because it was so fundamental.
Once again, medicine stands before a question.
Should the human body be viewed as a collection of separate organs, or as a single system in constant coordination? Interest in the autonomic nervous system is not merely about identifying new disorders - it may represent a transformation in how we understand the human body itself.
And that transformation has already begun.