Stanford neurobiologist Andrew Huberman discusses the two things we can always control, even during a high-stress election and scary COVID pandemic -
By Jessica Wapner on November 16, 2020
What is stress?
"Stress is one position along the continuum of what we call autonomic arousal. At one end of this continuum would be somebody in a coma. At the very other end of that continuum is a full-blown panic attack: heart racing, pupils dilating, hyperventilating. In between we have lower levels of stress [and the states of being] alert and focused, sleepy and asleep. Stress is generally a high level of autonomic arousal. It was designed to be a generic response to mobilize the body.
Sometimes that’s well matched to the demands of life. If you need to run and catch your train, you want all the things that go along with stress to go pursue that train. But if the stress response is spontaneous or excessive, it can start to feel pathological."
What is stress’s relationship to vision?
"When you see something exciting or stressful—a news headline, a fraudulent credit-card charge—heart rate increases; breathing increases. One of the most powerful changes is with vision. The pupils dilate, and there’s a change in the position of the lens in the eye. Your visual system goes into the equivalent of portrait mode on a smartphone. Your field of vision narrows. You see one thing in sharper relief, and everything else becomes blurry. Your eyeballs rotate just slightly toward your nose, which sets your depth of field and focus on a single location. This is a primitive and ancient mechanism by which stress controls the visual field."
How does this visual mode affect the body?
This focal vision activates the sympathetic nervous system. All the neurons from your neck to the top of your pelvis get activated at once and deploy a bunch of transmitters and chemicals that make you feel agitated and want to move.
Why is the visual field so connected to this brain state?
"Something that most people don’t appreciate is that the eyes are actually two pieces of brain. They are not connected to the brain; they are brain. During development, the eyes are part of the embryonic forebrain. Your eyes get extruded from the skull during the first trimester, and then they reconnect to the rest of the brain. So they’re part of the central nervous system.
Having the eyes outside the skull orients the organism to the time of day. But it also means that you’ve got two pieces of brain that can register events in the environment at a distance in order to adjust the overall state of alertness in the rest of the brain and body. It would be terrible if we had to wait until things were in contact with us before we could prepare to react to them."
Is there a visual mode associated with calmness that can change our stress levels?
"Yes: panoramic vision, or optic flow. When [you] look at a horizon or at a broad vista, you don’t look at one thing for very long. If you keep your head still, you can dilate your gaze so you can see far into the periphery—above, below and to the sides of you. That mode of vision releases a mechanism in the brain stem involved in vigilance and arousal.
We can actually turn off the stress response by changing the way that we are viewing our environment, regardless of what’s in that environment."
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