Why do I have anxiety? The body’s fight or flight response


Editorial Team


February 3, 2021

older woman with slight smile understanding what anxiety means
Learn why anxiety happens and how you can work with anxious feelings in the most constructive way possible.

If you have anxiety, you’re probably familiar with how it feels—racing heart, feeling like you can’t breathe, tight muscles, sweating. But what you might not know is that the physical experience of anxiety is a byproduct of the body’s threat response system. Learning why you have anxiety and where it came from can help you better understand what anxiety means and the best ways to manage it.

For people with anxiety and depression, purposefully engaging in pleasurable activities can improve mental health.
Learn why anxiety happens and how you can work with anxious feelings in the most constructive way possible.

If you have anxiety, you’re probably familiar with how it feels—racing heart, feeling like you can’t breathe, tight muscles, sweating. But what you might not know is that the physical experience of anxiety is a byproduct of the body’s threat response system. Learning why you have anxiety and where it came from can help you better understand what anxiety means and the best ways to manage it.

What is anxiety?

The term anxiety is used so often these days that it can be challenging to understand the definition of anxiety, especially in a biological sense.

Is it a feeling? An emotion? What’s the difference between stress and anxiety? If you feel anxious, does it mean you have a clinical disorder? What about feelings of anxiety vs. nervous feelings?

While it’s not an emotion, like joy, sadness, fear, anger, or disgust, you can certainly feel anxiety in your body. In that way, it can be seen as a feeling because you are literally feeling it.

To clarify, let’s use a biological definition: anxiety is your body’s natural reaction to the stress you experience when something threatens your emotional, psychological, or physical safety.

Stress is another term you probably hear often and in different contexts. But in biological terms, stress is understood in a specific way. A stressor is any external factor that threatens your well-being.

It’s important to understand that both stress and anxiety are normal parts of the human experience. Everyone feels anxious and stressed at times, and just because you experience anxious feelings as a response to stress doesn’t mean you have a clinical disorder.

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Why am I anxious?

Again, anxiety is your body’s natural reaction to a stressor, either real or perceived, that threatens your emotional, psychological, or physical well-being.

When you come into contact with stressors, your brain triggers a stress response by releasing certain chemicals. These, in turn, cause physiological changes in your body.

The part of the brain that causes these chemicals to be released is called the amygdala. When it perceives a threat, it automatically awakens the sympathetic nervous system, which is responsible for the involuntary physiological response to danger. And when activated, this system sends signals throughout the body, compelling it to react.

That’s why feeling anxious is your body’s way of making sure you’re ready to spring into action. In other words, what anxiety means for your body is “get ready”—something dangerous may be headed this way.

You’ve probably heard people talk about the fight, flight, or freeze responses. This is just another name for anxiety or the body’s threat response system.

Chances are, you’ve experienced some of the physiological sensations associated with anxiety—tight chest, racing heart, shallow breathing, stomach pains, tense muscles, dilated pupils, and sweaty palms. Think of the sensations you feel in your body as evolutionary responses designed to warn and protect you from danger.

When anxiety comes from an inaccurate appraisal of danger, it may feel anything but helpful.  Understandably, you want your anxious feelings to just go away. Explaining anxiety from a biological perspective can help foster greater understanding and better equip you to manage the experience.

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Why do I have anxiety?

It probably doesn’t feel like it when you have intensely anxious feelings, but anxiety is useful. To begin with, it helped early humans survive the very threatening world they lived in and is one of the reasons human beings are still around.

And even though many of the anxiety responses we experience these days may be an overreaction to stressors, anxiety isn’t always a bad thing.

Everyday anxiety guides and protects us from typical environmental threats. If it’s working in an adaptive way, the anxiety usually subsides when the stressor goes away. Plus, it can help motivate us.

Imagine if you were studying for a big exam but had no anxious feelings. You might lose motivation and eventually give up. Research has shown that you can actually learn to harness moderate anxiety as a driver for success.

In other words, if you can find helpful ways to relate to anxious feelings, you may be able to let them help motivate and guide you through life. You can work through some of the less desirable symptoms while still appreciating the purpose it serves. Many find that the negative impacts of anxiety ease up when we accept the experience.

But some people have ongoing, extreme anxiety. At this point, it’s no longer adaptive or helpful. Anxiety becomes an issue when it persists even when the stressor has passed, occurs for no apparent reason, leads to avoidance, impedes daily functioning, or causes panic attacks.

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What is an anxiety disorder?

Some anxiety is normal, but when does it cross the line and become a disorder? If anxiety has become an extreme, persistent, and unavoidable part of your life, you may have a disorder. This is what we’d refer to as clinical anxiety.

From a more practical perspective, if anxious feelings get in the way of living your life and performing basic daily tasks, it’s probably a good idea to talk to a mental health or medical professional. You’re not alone. Anxiety disorders are the most prevalent mental health disorders in the United States, impacting almost 34% of people at some point in their lives.

Here are some of the most common symptoms.

  • Feeling restless, tense, and on-edge
  • Not being able to stop worrying
  • Increased heart rate
  • Rapid breathing or feeling like you can’t breathe
  • Worry that’s out of proportion to an event or circumstance
  • Not being able to concentrate
  • Shaking or trembling
  • Muscle tightness and tension
  • Nausea and other gastrointestinal issues
  • Sweating

Chronic vs. acute anxiety

The body’s response to stress can vary depending upon the form, length, and severity of the stressor. An ongoing stressor, such as a global pandemic, can cause you to feel an undercurrent of anxiety for an extended period.

While you’re able to function on a daily basis, you may experience difficulty concentrating or falling asleep. The anxious feelings, while mild, are ongoing or chronic. It may be helpful to learn some distress tolerance skills to help you cope with the continued strain.

In contrast, an acute stress reaction can occur following a significant event such as a car accident or physical assault.

In these cases, the body’s anxiety reaction comes on fast and strong and can last for several hours or days. When you’re experiencing an acute anxiety response, your daily functioning will typically be quite impaired.

We know that the experience of intense, ongoing anxiety can feel isolating and hopeless. But there is hope and help available. Both chronic and acute anxiety are conditions that respond to treatment. If you’re experiencing anxiety or want to support someone who is, there are many effective options to try.

Treating anxiety

Anxiety can feel overwhelming. But if we understand what’s happening in our bodies, we have a better chance of developing coping skills to manage it. There are 3 main approaches to treatment, and most people find that they’re most effective when appropriately combined.

A trained clinician can work with you to determine which intervention, or combination of interventions, is best for you.


Therapy is one helpful approach for people with anxiety disorders. Depending on the type of therapy you choose, it can be a tool to help you address emotional patterns, learn new strategies, get in touch with and work through feelings, understand childhood experiences, process past trauma, and much more.

Cognitive behavioral therapy (CBT) is a type of psychotherapy that teaches you new ways of thinking and behaving when you encounter stressors. CBT is one of the most common interventions because it can help shift your relationship with the stressors themselves and anxious feelings in general. It can also help shift unhelpful patterns of thinkingrumination, and negative self-talk.

Prescription medication

Medication works with your brain chemistry to help calm some of your automatic responses.

An antidepressant medication called selective serotonin reuptake inhibitors (SSRI) is an effective and non-habit-forming way to help people with anxiety. Some brand-name examples of these meds are ProzacLexaproZoloft, Celexa, and Paxil.

If you’re interested in trying SSRIs, telehealth services make it easy and straightforward to connect with a medical professional. Visit Lemonaid to get anxiety treatment and an online prescription today.

Lifestyle changes

There are also changes you can make to your daily life that have a significant impact on anxiety. Learning new coping skills and strategies may help reduce anxiety, especially when combined with other treatment approaches.

Here are some lifestyle changes that can help with anxiety.

  • Getting some exercise
  • Making enough time to rest
  • Eating a balanced diet of healthy foods that make you feel good
  • Staying away from caffeine, alcohol, and sugar
  • Trying meditation, mindfulness, yoga, or other relaxing exercises
  • Using cognitive techniques to shift the way you relate to anxiety
  • Talking to safe people about how it impacts you

We know how debilitating anxiety can be, but the right treatment or combination of treatments can help you overcome it. Visit Lemonaid to talk with a medical professional about the right options for you.


  • Anxiety is a normal part of life and an intelligent, adaptive part of human development.
  • But when it’s severe and ongoing, it can have a significant negative impact on your life.
  • If anxious feelings make it hard to function, it’s probably time to seek professional help.
  • You can treat anxiety with therapy, prescription medications, and lifestyle changes.
  1. Bandelow & Michaelis (2015). Epidemiology of anxiety disorders in the 21st centuryhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4610617/
  2. Epel et al. (2010). Embodying Psychological Thriving: Physical Thriving in Response to Stress. https://psycnet.apa.org/doi/10.1111/0022-4537.671998067 
  3. Rynn & Brawman-Mintzer (2004). Generalized anxiety disorder: acute and chronic treatmenthttps://pubmed.ncbi.nlm.nih.gov/15448583/


Editorial Team


February 3, 2021

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment or medication.