What is This Feeling, so Sudden and New? Explaining The Physical Symptoms of Anxiety
Author: Sophia Marchetti
Have you ever felt your heart race, your palms sweat, or a tight knot form in your stomach when you’re stressed or worried? It’s not all in your head-Anxiety can physically impact you, too. Maybe you’ve gotten so anxious that you felt exhausted all of a sudden, or couldn’t speak. But why does our body react this way? To understand this, we need to take a quick trip back in time.
The physical symptoms of anxiety are part of an ancient survival system commonly known as the fight-or-flight response. When you encounter a threat—whether it’s a woolly mammoth or a modern-day public speaking competition—your body may automatically go on high alert. This reaction is triggered by the release of hormones like adrenaline and cortisol, which prepare your body to either fight the danger, flee from it, or, in some situations, freeze in place. 1
The freeze response is often overlooked, but it is just as vital as fight or flight! When you’re faced with a threat but feel like you can’t fight or run away, freezing is your next best option. Just like possums “play dead,” hoping the danger won’t notice them, human bodies can do the same. This response, like fight or flight, has been fine-tuned by millions of years of evolution to be incredibly effective in moments requiring immediate action. The previously mentioned hormones (adrenaline and cortisol) increase your heart rate, elevate blood pressure, and boost blood flow to your muscles to make you more alert and physically ready to survive. 2 However, nowadays, these same reactions are often triggered by less life-threatening scenarios, like taking a driver’s test. The disconnect between the body’s physical response and the actual, usually minimal level of danger is why anxiety can sometimes feel so overwhelming.
So, what do those symptoms look like? Here’s a non-exhaustive list of some more common symptoms and why they occur. 3 One common symptom of anxiety is an increased heart rate and rapid breathing. Adrenaline causes you to breathe quicker and your heart to pump faster, delivering more oxygen to your muscles and brain. While this is useful if you’re about to outrun or fight a predator, it’s less helpful when you’re nervous about a test.
In addition, anxiety can make your muscles tense up, especially in your shoulders, neck, and jaw. This is because your body is bracing for action, whether that be fighting, fleeing, or freezing. Think of a predator seeing its prey—they tense up for a fight, preparing to pounce on their next meal!
Sometimes, anxiety can cause digestive issues, like nausea or butterflies in your stomach. When in fight-or-flight mode, your usual digestive functions are temporarily “shut down”, as your body prioritizes resources for more immediate survival needs, focusing less on keeping your food down.
Another physical symptom that many are familiar with is sweating! This helps cool the body down during physical exertion. When you’re anxious, the body perceives a need to “cool off” during your stress response, even though you may not actually be exerting yourself.
A final common symptom that often surprises people is feeling tired. While fight-or-flight responses speed up heart rate and breathing, the freeze response can sometimes cause your heart rate to drop, and breathing may slow down or even stop for a moment. Think back to possums playing dead! This strategy would help us fall asleep, seem dead, or remain as still as possible to avoid detection.
When your brain—specifically the emotional centre (your amygdala)—detects a potential threat, it tells the nervous system and body to react. In the absence of actual danger, those reactions can feel disproportionate to the situation, and make you question them. If the threat was real, you wouldn’t feel the need to figure out why you react in these ways and it would all make much more sense. “My heart rate went up because I needed to run away from the pack of sabre tooth tigers that were chasing me,” makes more sense in terms of a threat than, “My heart rate went up because I needed to microwave my spaghetti in the staff lunch room and it’s very busy in there.”
Fortunately, there are ways to manage the physical symptoms of anxiety. Deep breathing, mindfulness, and physical exercise can help regulate the 3 F responses. By engaging the parasympathetic nervous system—which we sometimes call the “rest and digest” system—you can bring your body back to its non-anxious baseline.4
So, it’s not all in your head. But it’s also not your body betraying you—it’s simply a case of your ancient survival instincts being a little too eager for modern-day challenges.
Price, J. S., 2003. Evolutionary aspects of anxiety disorders. Dialogues in Clinical Neuroscience, 5(3), pp. 223–236. Available at: https://doi.org/10.31887/DCNS.2003.5.3/jprice [Accessed 24 February 2025].
Mayo Clinic, 2023. Stress management. Available at: https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress/art-20046037#:~:text=Adrenaline%20makes%20the%20heart%20beat,the%20body%20that%20repair%20tissues [Accessed 24 February 2025].
Mayo Clinic, 2023. Stress management. Mayo Clinic. Available at: https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress/art-20046037#:~:text=Adrenaline%20makes%20the%20heart%20beat,the%20body%20that%20repair%20tissues [Accessed 24 February 2025].
Nunez, K., 2023. Fight, Flight, Freeze: What This Response Means. Healthline. Available at: https://www.healthline.com/health/mental-health/fight-flight-freeze [Accessed 24 February 2025].
