Did you know nearly 75% of adults report feeling stressed on a regular basis? Yet most of us don’t really understand what stress is — or why it makes our heart race, our mind go blank, or our stomach twist. In today’s fast-paced world, stress has become an almost constant companion, but what’s actually happening inside your body when stress takes over?
Psychological pressures, not physical danger, are now the most common triggers of our body’s stress response. Whether it’s an upcoming work deadline or tension in a relationship, our bodies still react as if we’re facing a life or death situation. From adrenaline surges to brain fog, here’s how your body responds to stress and why understanding it can help you feel more in control.
The Science of the Fight or Flight Response
The fight or flight response is your body’s automatic reaction to perceived threats. Think of the amygdala as your brain’s smoke alarm. When it senses something “off,” it promptly alerts the hypothalamus, like calling 911. From there, your body goes into emergency mode, flooding your system with stress hormones like adrenaline and cortisol. These hormones communicate with the rest of the body through the nervous system, preparing it with energy to either confront the danger (fight) or flee from it (flight).
For our ancestors, this response helped ensure survival in physically dangerous situations. But today, it’s often triggered by things like an overwhelming inbox or a difficult conversation. Even though these aren’t physical threats, your body still responds as if you’re in danger. (If you’re curious about how the mid-brain relays signals to the rest of the body, check out my earlier article, “Your Body Is Talking, Are You Listening?” where I explore this in more detail).
How the Brain and Body Respond to Stress
When stress hits, your body undergoes several rapid changes to prepare for action. Here are a few of the key ones:
- Increased heart rate and blood pressure: Blood rushes to muscles and organs, getting the body ready for action.
- A burst of glucose: This provides your muscles fast fuel in case you need to sprint or react fast.
- Heightened alertness: Extra oxygen is sent to the brain to help you think more clearly and react faster.
- Suppressed non-essential functions: Digestion slows, allowing the body to focus energy on dealing with the immediate threat.
These changes occur so quickly that we often react instinctively before our conscious brain has a chance to fully process the danger, like jumping out of the way of a speeding car.
In an age of constant information overload and persistent psychological pressures, our stress response is often activated by non-physical threats. When left unmanaged, this chronic activation can take a serious toll on our health and well-being.
Myth – “Stress is just in your head”
Reality – Stress starts in the brain, but it doesn’t stay there. Chronic stress rewires your brain, weakens your body, and drains your energy.
The fight-or-flight response can be helpful in the right situations; it’s what gives you the burst of energy to meet a deadline or react quickly in an emergency. But when it gets triggered too often or doesn’t shut off, it can cause more harm than good.
Understanding how stress affects your body isn’t just interesting science, it’s a powerful step toward managing it. When your system is flooded with stress hormones like cortisol for long periods, it can:
- Increase the risk of anxiety and depression
- Raise the risk of heart disease
- Weaken the immune system, making illness more likely
- Disrupt sleep, both falling asleep and staying asleep
Over time, chronic stress can leave you feeling drained; emotionally, mentally, and physically — and make it harder to manage and bounce back from everyday challenges.
Here’s the important takeaway: while short-term stress (also called eustress) can help you stay sharp and focused, long-term stress wears you down. Learning how it works is the first step to regaining control.
Managing Stress: Strategies to Tame the Fight or Flight Response
Thankfully, you’re not stuck in survival mode. There are several effective ways to manage stress and prevent your fight or flight response from going into overdrive:
1. Practice Deep Breathing Exercises: Deep breathing activates the parasympathetic nervous system, which is like your body’s natural “calm switch”. Just a few minutes of slow, deep breaths a day can start to counteract the stress response. The British Heart Foundation website has easy techniques to get started.
2. Try Mindfulness Meditation: Meditation isn’t just about sitting in silence, it’s a way to train your mind to stay grounded, especially when things feel overwhelming. By increasing activity in the prefrontal cortex, it enhances emotional regulation and decision-making, allowing you to respond to stressors with increased clarity.
3. Stay Active: Physical activity is one of the most powerful (and underrated) stress relievers. Exercise clears out excess adrenaline. It also helps lower cortisol levels, which can leave you feeling calmer and more balanced, often within a few minutes. Personally, even a ten minute walk at lunch helps clear my head on hectic days.
Regain Control of Your Fight or Flight Response
The fight or flight response isn’t your enemy, it’s your body trying to protect you; but when modern life keeps flipping that internal alarm switch, you need tools to reset.
In today’s world, that internal alarm often goes off when there’s no real physical danger. By understanding how your body reacts, you get back the power to reset and respond, not just react.
Try one small change this week: take a few deep breaths before bed, go for a walk, or schedule a mindful mid-day pause. With a little awareness and practice, you can start to regain control, feel more centered, and keep yourself grounded, no matter what life throws your way.
Resources
Stress in America 2023 (2023). American Psychological Association: Stress in America Report (2023)
Chu B, Marwaha K, Sanvictores T, et al. Physiology, Stress Reaction. [Updated 2024 May 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK541120/
Understanding the Stress Response (2024). https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response
3 Breathing Exercises to Relieve Stress (2023). https://www.bhf.org.uk/informationsupport/heart-matters-magazine/wellbeing/breathing-exercises American Adults Express Increasing Anxiousness in Annual Poll; Stress and Sleep are Key Factors Impacting Mental Health (2024). https://www.psychiatry.org/news-room/news-releases/annual-poll-adults-express-increasing-anxiousness
