How Does Anxiety Works in My Body? A Psychologist Explains It Simply

Anxiety activates the HPA axis the Hypothalamic-Pituitary-Adrenal system. The hypothalamus detects a threat and signals the pituitary, which signals the adrenal glands to release adrenaline, redirecting blood from the brain to the muscles. Teaching children the biology behind their anxiety transforms it from a personal failing into a neurological process they can understand and manage.

In 25 years of private practice evaluating children, teenagers, and young adults, I spent a lot of time on the floor with big pieces of presentation paper, drawing terrible pictures of bodies and brains.

Words alone don’t mean much when you’re trying to explain feelings, especially to kids, but honestly, to most adults too. You need pictures to go with the words.

When people understand the why behind the what, everything changes. The conversation shifts from being about their character, who they are as a person, to being about their neurology. Their wiring. Something outside of their personhood that can be understood, worked with, and changed.

Most of the kids I worked with developed an attitude of, “It’s me against my brain,” and they set about strengthening their weaknesses with genuine determination. I always told them: don’t judge your entire body by the lousy job your hair is doing today. Control the controllable.

Why Does Anxiety Exist?

The anxiety response, that surge of adrenaline that makes your heart pound and your hands shake; is an ancient, extraordinarily powerful survival mechanism. Prehistoric humans needed it to fight or flee from genuine physical threats. Woolly mammoths. Predators. Real danger. It is so important to survival that it is still fully intact in us today, even though woolly mammoths are no longer a concern.

Anxiety is the number one mental health issue in today’s society.

When the anxiety response fires constantly, the body dumps adrenaline and eventually cortisol in a chronic, relentless cycle. Both hormones, over time, erode health. They contribute to high blood pressure, diabetes, weight gain, sleep problems, depression, and more anxiety. The system designed to protect us begins to damage us.

Here’s something most people don’t realize: the anxiety response frequently begins before you consciously know it’s happening. Part of your nervous system detects threats even before your conscious mind registers them. It’s instinct, riding just beneath your awareness of the world. Children have this too. It is not a choice. It is neurology.

Three Organs Behind Every Anxious Moment

The anxiety response is driven by three organs that make up the HPA, “Hypothalamic-Pituitary-Adrenal” axis. These organs are part of the endocrine system, which dumps hormones directly into the bloodstream for fast, powerful action:

1. Hypothalamus:  The body’s balance keeper and is responsible for regulating temperature, thirst, hunger, sleep, mood, and sex drive. Small in size, enormous in importance.

2. Pituitary Gland:  About the size of a pea. Responsible for regulating growth, blood pressure, the thyroid, the sex organs, metabolism, pregnancy, childbirth, breastfeeding, body temperature, and pain relief. Tiny and extraordinarily powerful.

3. Adrenal Glands: Release adrenaline, the hormone that redirects blood flow away from the brain and into the lungs and major muscle groups. It is the hormone that says: stop thinking and start running. This is why you can feel lightheaded when you’re anxious. Because the adrenal glands sit on a fat pad on top of the kidneys, it also makes perfect anatomical sense that you feel the urge to urinate when you’re nervous or excited.

One more thing worth noting: nervous and excited feel exactly the same in the body. The difference is your interpretation of the event, whether you stay and get on the roller coaster or run from the woolly mammoth.

How to Explain Anxiety to a Child?

This is the part that works. Grab a big piece of paper.

Step 1: Draw a ridiculously bad outline of a human body. This is usually the part everyone laughs at. That’s fine, the laughter is part of the learning.

Step 2: Draw a small circle in the brain area, that’s the hypothalamus. Put a smaller circle inside it, that’s the pituitary gland. Draw a kidney shape in the abdomen, that’s where the adrenal glands live. Give them names if you want. ‘Fred’ works. Whatever is memorable.

Step 3: Explain that the hypothalamus (Fred) is responsible for keeping everything in balance. Stand on one leg to demonstrate balance. The better the show, the more they’ll remember.

Step 4: Explain that Fred can’t talk to the adrenal glands directly, he has to call the pituitary gland first. Mime making a phone call while balancing on one leg: ‘Hello, pituitary? It’s Fred. We have a SITUATION.’ The pituitary then calls the adrenals.

Step 5: The adrenals unleash the adrenaline. The body prepares to fight or flee.

Draw the line connecting hypothalamus → pituitary → adrenals. That is the HPA Axis.

Now explain, when this happened to cave people, they needed every bit of that energy to escape a real physical threat. But today, we don’t have dinosaurs. We have imaginations. We imagine things that feel threatening but can’t actually hurt us, like a spelling test.

What Anxiety Feels Like in the Body?

Teach your children to recognize these as the signs that their adrenal glands have fired:

• Shaking hands, shaking body, shaking voice
• Heart pounding hard and fast
• Dry mouth
• Feeling like crying or running away
• Needing to use the bathroom
• Feeling scared – or strangely, feeling excited

These are not signs that something is wrong with them. These are signs that their ancient survival system is working exactly as designed. The problem is that it’s responding to the wrong things.

What to Do About Anxiety? Interoceptive Exposure

Here is one of the most powerful tools available for teaching children to reduce the fear of their own anxiety symptoms.

It is called interoceptive exposure and the principle is simple: the sensations that frighten us lose their power when we learn to create them intentionally.

Jumping jacks. Running in place. Squeezing and releasing muscle groups. Standing and stretching vigorously. These activities create the same physical sensations as anxiety such as a pounding heart, shaking, breathlessness. When children learn that they can choose to create these feelings, the feelings stop feeling like something happening to them. The feelings become something they can control.

We learned to be afraid of these sensations. We can unlearn it.

The Most Powerful Factor: Anticipatory Anxiety

Franklin D. Roosevelt said: “The only thing we have to fear is fear itself.”

That is a perfect description of anticipatory anxiety, rehearsing to be anxious. Preparing for the fear before the threat has even arrived.

It’s best to learn not to bleed until you’ve been cut.

Ask your children: “How likely is it that this will actually happen?” Help them take it one morning at a time. One afternoon at a time.

And teach them this above everything else: Teach them that if the thing they fear does happen, they will be able to cope. Because their family loves them. Because they have survived hard things before, remind them of the fears they have already overcome.

Please do not tell them they’ll be fine. Fine is not a coping strategy. Tell them instead: “I have confidence that you can handle this.” They won’t feel fine. But they will be alright if they hang in. That is a different and far more honest promise.

When to Get Help for Anxiety?

This process takes practice. Stick with it.

If anxiety cannot be brought under control with these strategies, get professional help. These children are truly suffering. Anxiety rarely improves on its own and untreated anxiety has a direct pathway into depression. Depression is serious. Do not wait for it to arrive.

Antidepressant medications work in part by interrupting the HPA axis and giving the nervous system a chance to quiet down enough for children to actually learn and practice the coping skills that will serve them for life. Medication is not failure. For some children it is the bridge that makes everything else possible.

Don’t judge your entire body by the lousy job your hair is doing today.

Control the controllable.

Note: If your child is struggling with anxiety, depression, or other mental health challenges, professional support is available. If you are experiencing a mental health crisis, contact the 988 Suicide & Crisis Lifeline by calling or texting 988.

Browse more articles on anxiety, mental health, and coping strategies:

Anixety Frequently Asked Questions (FAQs)

How does Anxiety Work in the Body?

Anxiety activates the body’s fight-or-flight system, also known as the HPA axis. When a perceived threat is detected, the hypothalamus signals the pituitary gland, which then tells the adrenal glands to release adrenaline and cortisol, preparing the body to respond, even if the threat is not physically dangerous.

Why does Anxiety Feel Physical Instead of Emotional?

Anxiety is a neurological and hormonal response, not just an emotion. Stress hormones redirect blood flow to muscles and lungs and away from the brain, causing physical sensations such as shaking, rapid heartbeat, dizziness, nausea, and the urge to flee.

What is the HPA axis in simple terms?

HPA axis is the body’s alarm system involving the hypothalamus, pituitary gland, and adrenal glands. It detects threats and rapidly releases stress hormones to prepare the body for action.

Why do Kids get Anxious even when “Nothing Bad” is Happening?

Children may experience anxiety due to anticipation, imagination, or fear of embarrassment. The brain can activate the stress response before conscious awareness, causing the body to react as if danger is real.

What is Anticipatory Anxiety?

Anticipatory anxiety occurs when the body reacts to a future event that may or may not happen. The fear of anxiety itself becomes the trigger, reinforcing a cycle of stress before the event occurs.

What is Interoceptive Exposure for Anxiety?

Interoceptive exposure is a therapeutic technique where individuals intentionally recreate physical sensations of anxiety in a controlled setting, helping reduce fear by demonstrating that these sensations are safe and manageable.

How Should Parents Talk to Kids about Anxiety?

Parents should explain anxiety as a body-based process rather than a personal weakness. Emphasizing coping skills, emotional regulation, and support helps children feel more in control.

When Should Parents Seek Professional Help for Anxiety?

Professional help is recommended when anxiety interferes with daily functioning, worsens over time, or leads to withdrawal, sleep disruption, or depression. Early intervention improves outcomes significantly.