Your Brain on Anxiety: Its Role and How it Affects You

If you feel like stress and anxiety are taking over your daily life, you are not alone. Anxiety is one of the most common psychiatric disorders, occurring more frequently in females than males, with a 2:1 ratio (1). According to the Anxiety and Depression Association of America, more than 40 million adults ages 18 and older are affected with Anxiety disorders (2). Many more people do not seek help for anxiety or do not receive a proper diagnosis from their doctors (1). This is understandable, as many people may believe anxiety is a normal part of everyday life. While this is true to some extent, anxiety can also manifest into something much bigger, which can end up affecting our overall health, daily life, and relationships.

Daily life occurrences such as starting a new job, giving a presentation, or preparing for a big game are examples of normal anxiety situations. They can also include worry over finances, a breakup, an awkward or embarrassing social situation, or even fear of an object, place, or situation. 


The symptoms that can arise from these daily circumstances can present themselves in four different ways (1):

  • Physical symptoms: shortness of breath, sweating, increased heart rate, feeling tired or weak, trembling 
  • Anxious thoughts: worry or fearing the worst-case scenario
  • Behavioral symptoms: compulsive behavior, second-guessing oneself, avoiding certain events or social situations
  • Emotional symptoms: nervousness, feeling tense, fearful, impatient, frustrated

So, if we all have stress and anxiety as part of our daily lives, how do we understand the difference between the two? Well, stress is the external factor. For example, getting stuck in traffic, arguing with a coworker or significant other, or nervousness before a job interview. Anxiety is then your body’s internal response to this stressor (6). 

It is inevitable that we will regularly have these daily stressors and will deal with the resulting anxiety. However, when your anxiety begins to manifest itself in more powerful ways, consuming your daily thoughts and behaviors, something more may be going on. If you have constant, persistent stress and worry that culminates in irrational fear, avoidance of social situations, and other types of behavior affecting your health and relationships, you are likely dealing with an anxiety disorder.  

The different types of anxiety disorders can include (5): 

  • Generalized Anxiety Disorder-which is persistent or excessive anxiety around day to day life
  • Separation Anxiety Disorder- typically a childhood disorder, with anxiety related to separation from parents or parental figures 
  • Social Anxiety Disorder- high levels of fear, anxiety, and avoidance of social situations
  • Obsessive-Compulsive Disorder- unreasonable thoughts and fears leading to obsessive, repeated behaviors
  • Post Traumatic Stress Disorder (or PTSD)
  • Selective Mutism- which is the failure to speak in certain places or situations
  • Panic Disorder- intense anxiety or fear that reaches a peak in minutes (often known as panic attacks)
  • Agoraphobia or the fear of places or situations, leading to avoidance
  • Specific Phobias (think spiders, heights, germs)
  • Substance-induced Anxiety Disorder- the result of abusing drugs, taking medications or chemical exposure or drug withdrawal

How Does Anxiety Occur: 

Let’s dive deeper into your brain’s response to the outside stressors we talked about earlier. We learn that through evolution, all humans have an automatic defense mechanism. This active response is the “fight or flight” response (8). 

When we face these outside stressors, our brain assesses the situation and decides whether it is harmful or not (3). 

During caveman times, dangers used to be all around us. We were constantly fighting to survive harsh weather, find food and protect ourselves from predators. This active response of fight or flight helped to keep us alive. This response has stayed with us until today. 

A publication in Harvard Health, “Understanding the Stress Response” (7) thoroughly outlines the process in our brain during this active response:

When your brain witnesses a scenario, it sends a signal to the amygdala or the emotional processing part of the brain. A distress signal gets sent to the hypothalamus. The hypothalamus then sends a message to the rest of your body, communicating with your Autonomic nervous system. This system controls your breathing, blood pressure, heart rate, and more. The autonomic nervous system consists of two parts. These two parts are the sympathetic nervous system (which is how your body reacts to danger) and the parasympathetic nervous system (which brings your body back to homeostasis, or a relaxed state). The amygdala sends a distress signal and then the hypothalamus activates the sympathetic nervous system by sending signals to the adrenal glands. Those glands create epinephrine (or what we know as adrenaline). This is when the physiological symptoms begin, such as increased heart rate, increased blood pressure, expanded lung airways, and more.

As that adrenaline subsides, the second element of the stress system is activated. This second component is the HPA axis, composed of the hypothalamus, the pituitary gland, and the adrenal glands. The HPA axis depends on hormonal signals to keep the sympathetic nervous system in reactive mode. The hypothalamus releases a corticotropin-releasing hormone that travels to the pituitary gland, triggering the adrenocorticotropic hormone. This hormone moves to the adrenal glands, releasing cortisol and keeping the body on high alert. When the danger is gone, cortisol levels will fall. Then the parasympathetic nervous system relaxes the body, removing the stress response. 

The two systems (sympathetic and parasympathetic systems) need to work together. If we are constantly in this active response state, the stress and toll it is taking on our bodies can be detrimental to our health, both mentally and physically. When we don’t have a way to turn off the active response and return to a normal state we will remain in that chronic state of anxiety (7).

Today, we aren’t fighting to survive, figuring out when our next meal will be, or steering clear of any lions, however, our bodies can still react to our current stressors and our physiological and mental stress in the same manner as it did for our early ancestors. (4). Additionally, because we use our minds to create feelings and events from the past or images from an imagined future, the response is still the same regardless of whether our body’s defense system is then activated (8). 

How chronic anxiety can affect your physical and mental health

Chronic anxiety or staying in this constant reactive state can create many different health issues (9). These can include:

  • Suppressed immune system
  • Digestive problems
  • Muscle tension
  • Short-term memory loss
  • Substance misuse
  • Insomnia
  • Headaches
  • Social isolation
  • Poor quality of life
  • Depression

Stress is not making you ill; your response to that stress creates physical illnesses. With the imbalance of your sympathetic nervous system and your parasympathetic nervous system, your body is unable to return itself to a relaxed state. Therefore, it would be beneficial to take some of the following actions to help relieve this (9). 

  • Speak with your doctor- discuss your concerns and have them rule out other health problems
  • Exercise daily- chemicals are released during exercise that can benefit your immune system and help your body deal with stress under controlled circumstance
  • Eat a balanced diet- sometimes stress can lead to eating unhealthy, too little, or too much food
  • Limit your caffeine intake- caffeine can trigger the adrenal, which we discussed above, helps keep your body in that reactive state
  • Be aware of your worries- acknowledge them and try to let go to move forward
  • Find ways to relax- Deep breathing, meditation, calming music or yoga are all ways to help your body to relax and help you manage your stress levels
  • Meditate- this decreases those hormones of cortisol and adrenaline released during that fight or flight state
  • Have a solid social network- surround yourself with family and friends
  • Consider talking with a therapist- they can help you create coping strategies and methods

Understanding our body's reaction to stressors and finding ways to manage these reactions is key to maintaining our mental and physical health. 



(1) Chand, S. and Marwaha, R.
Chand, Suma, and Raman Marwaha. "Anxiety". Statpearls Publishing, 2020, p. ., Accessed 22 Apr 2021
(2) Understand the Facts | Anxiety and Depression Association of America, ADAA
"Understand The Facts | Anxiety And Depression Association Of America, ADAA". Adaa.Org, 2021, Accessed 22 Apr 2021.
(3) McEwen, Bruce S.
“Protective and damaging effects of stress mediators: central role of the brain.” Dialogues in clinical neuroscience vol. 8,4 (2006): 367-81. doi:10.31887/DCNS.2006.8.4/bmcewen
(4) What Happens to Your Body During the Fight or Flight Response?
"What Happens To Your Body During The Fight Or Flight Response?". Health Essentials From Cleveland Clinic, 2019, Accessed 22 Apr 2021.
(5) Anxiety disorders - Symptoms and causes
"Anxiety Disorders - Symptoms And Causes". Mayo Clinic, 2021, Accessed 22 Apr 2021.
(6) What’s the difference between stress and anxiety?
"What’s The Difference Between Stress And Anxiety?". Https://Www.Apa.Org, 2021,,the%20absence%20of%20a%20stressor. Accessed 22 Apr 2021.
(7) Publishing, H.
Publishing, Harvard. "Understanding The Stress Response - Harvard Health". Harvard Health, 2021, Accessed 22 Apr 2021.
(8) Kozlowska, K., Walker, P., McLean, L. and Carrive, P.
Kozlowska, Kasia et al. "Fear And The Defense Cascade". Harvard Review Of Psychiatry, vol 23, no. 4, 2015, pp. 263-287. Ovid Technologies (Wolters Kluwer Health), doi:10.1097/hrp.0000000000000065. Accessed 22 Apr 2021.
(9) Physical Effects of Worrying
"Physical Effects Of Worrying". Webmd, 2021, Accessed 22 Apr 2021.

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