How Stress Works and Why It’s So Bad for Your Health

by Auriel

Stress is pretty serious business. Not only is it an unpleasant experience that I’m sure we all wish we could avoid. But chronic stress is considered a risk factor for illnesses including cancer, heart disease, obesity and even premature death. Many are calling it the “silent killer.” That’s a little scary, wouldn’t you say?

We all know too much stress is bad for us, but do you know why

For a long time, I was skeptical about the effect of stress on my overall health and wellness. It just didn’t make sense to me that what I thought was a feeling—a mental or emotional reaction—could affect me physically. 

Psychologically, yes. It makes perfect sense that high levels of stress would lead to mental health issues like anxiety and depression. But how could other things like IBS or acne be explained by stress? Or even more serious chronic diseases?

It wasn’t until I learned how stress actually works in the body on a physiological level that things clicked. I finally saw all the ways stress was affecting me mentally, emotionally, AND physically. And once I got it, I realized I needed to take it seriously and address my chronically-high stress levels.

In this post I’m going to break down what happens in your body when it’s under stress and why it is likely affecting you more than you think. 

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What is Stress?

Simply put, stress is the body’s response to challenges that it may face. And these challenges, or stressors, come in many forms.

But stress is also a hardwired physical response and survival technique built into the body to protect you from harm. When experiencing stress, many chemical and biological processes occur that mobilize you to spring into action and avoid danger.

Back in the day, our ancestors relied on this stress-response to survive in the face of physical dangers. Back then, stress was encountering a bear in the forest. In contrast, our modern-day stressors look very different. They come in the form of:

  • Work anxiety
  • Health concerns
  • Financial difficulties
  • Pending deadlines
  • Never-ending to-do lists
  • Demanding social life
  • Relationships
  • Family conflicts
  • (Social) media
  • Pressure to achieve
  • FOMO
  • And so much more!

Unfortunately, the body doesn’t know the difference between being chased by a wild animal and a stressful job. It considers both to be a threat and responds in the same way.

Types of Stress

It’s important to note that not all stress is harmful. Some stress is completely normal. I mean, it’s impossible to avoid all stress completely. Stress can even be beneficial at times, pushing you to work harder or step outside your comfort zone or even conquer a fear.

This type of stress falls into the category of acute stress. This is momentary or short-term stress that is usually triggered by something specific like starting a new job or buying a home. It has a beginning and an end. This is the type of stress that we are biologically equipped to manage.

On the other hand, long-term stress that is experienced over a prolonged period is called chronic stress. This could look like constant worry over money or an unhappy relationship. It’s problematic because it keeps the body on high alert. Your system is constantly flooded with stress hormones and your body is unable to rest. Over time, chronic stress will affect your physical and mental health.

The Stress Response

Let’s get into how stress actually works in the body. 

When we perceive something as a stressor, the body is way ahead of us and kicks into action. The stress response starts in the brain and eventually makes its way through the entire body via the nervous system.

Stress and the Nervous System

A little background: the nervous system is comprised of your brain, spinal cord and nerves that extend to different organs and body parts. It’s made up of various systems that control everything from your thought processes and movements, to the everyday functioning of our cells and organs. It’s very extensive and complex.

But when talking about stress, the main player is the autonomic nervous system (ANS). The ANS controls all involuntary responses. That is, the things that our bodies do without us thinking about it–heart beating, fingernails growing, healing from cuts or injuries, for example. But also, our response to stress. 

The ANS has two branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). 

The sympathetic nervous system (SNS) – “Red Zone”

  •  The body enters fight, flight, or freeze mode
  • Prepares the body for action
  • Involved in the stress response

The parasympathetic nervous system (PNS) – “Green Zone”

  •  The body can rest, digest, repair, and reproduce (cells)
  • Calms the body
  • Energy is conserved

When the SNS is activated, the body believes it is in danger, this is the red zone. Alternatively, when the body believes it is safe and secure, the PNS is activated allowing the body to rest and recover, this is the green zone. 

We need both the SNS and PNS to keep us balanced. You can also think of the SNS as the body’s gas pedal and the PNS as the brakes. 

The green zone is our home base, allowing the body to function properly. The red zone our emergency responder, that keeps us safe.

The problem is that with all the psychological stress we experience daily, so many of us are living in the red zone most, if not all of the time. 

We’re constantly on high alert, ready to fight or flee and our bodies don’t get the opportunity to rest and repair. We’re basically living in survival mode and energy, oxygen, and nutrients are taken from the rest of our body to fight the perceived danger. Only this danger is not a bear in the woods, but an obnoxious boss or a lengthy to-do list.

Stress and the Body

When you experience stress, your body undergoes a physiological response that looks like this:

A stressor arises (e.g. a big presentation) and the stress response begins. 

The brain perceives the stressor and activates the SNS (you’re now in the red zone). This triggers the adrenal glands to release the hormones cortisol and adrenaline, which communicate to your cells that you are in danger. In response, many bodily changes occur to provide emergency fuel and energy to the most vital areas, preparing you for fight or flight.

Some of these physiological changes include:

  • Increased heart rate, pushing blood to muscles, heart and other vital organs, and extremities (arms and legs)
  • Increase in pulse and blood pressure
  • Heavy breathing, airways in the lungs expand        
  • Extra oxygen is sent to the brain to increase alertness
  • Sharpening of senses (sight-pupils dilated, hearing)
  • Blood sugar (glucose) and fat released into the bloodstream to provide more energy

After the initial threat, the body wants to return to the green zone, where it can rest and recover and get back to its normal functioning (i.e. the processes that keep us healthy). However, when stress lasts for too long or is triggered too often, your body remains in the red zone.

Why is this a problem?

Well, in the red zone, when the body is focused on trying to save your life, all of its resources go toward the critical organs – the heart, lungs, brain and the limbs (in case you have to make a run for it). There is little left over for the rest of the body, making it a little difficult to maintain a healthy system.

On the other hand, when the body is in the green zone, it can focus on resting, digesting, repairing and reproducing. Many important bodily functions take place in this mode. You are able to properly digest your food, absorb and distribute nutrients to our cells. You can rest and heal, allowing you to fight infection and for your cells to grow and function optimally.

When we remain in the red zone, constantly on high alert, sending out stress hormones and prolonging the stress response, the result is chronic stress and, ultimately, burnout. Over time, the body builds up some resistance and tolerance to the ongoing stress and panic. But never fully returning to a state of rest takes a toll on your health.

In a state of constant stress, we are more likely to suffer from:

  • Weakened immune system – reduced ability to fight and recover from illness
  • Mood issues – anger, depression, lack of energy, and poor sleep quality
  • Increased blood pressure and heart rate, higher cholesterol, and risk of heart attack
  • Digestive issues – IBS, acid reflux, and nausea
  • Weight gain due to increased fat storage and disrupted hunger cues
  • Loss of libido and irregular menstrual cycles
  • Muscle and joint pain
  • Lower bone density

The Far-Reaching Effects of Stress

Hopefully, you can see that stress is certainly not just in our minds (as I once thought), but impacts our entire body – physically, mentally, and emotionally. I want to go a little more in detail on a few areas that are often affected by stress. If you are suffering from chronic stress, you may be experiencing these effects right now.


I’m sure you have experienced stress-related cravings. The desire to eat junk or comfort food when you’re stressed out. This isn’t just an emotional coping method, but actually has to do with the body’s need for glucose. When you’re under stress, the body wants to get you the most efficient, fast-burning fuel and that is glucose (sugars and carbs).

During the stress response our blood sugar goes up (as more glucose is made available in the blood) and our glucose reserves are depleted. The body begins to fear that it won’t have enough glucose to fuel you in the future. And this is when the body starts to crave sweets and carbs to replenish the stores of glucose. So, cravings are not just emotional, but often biological.

Additionally, there is another option for fuel: fat. And this is the ideal fuel that we would like our bodies to utilizes. However, glucose is the faster burning source of energy. So, when you are constantly in the red zone, you are burning more glucose (instead of fat) and craving more sugary foods to replace it. When you are in the green zone, your body is better able to burn fat and use it as fuel. This gives some insight into why stress and weight gain tend to go hand in hand.


When you have constant low-level stress and your SNS is turned on, adrenaline remains in your bloodstream keeping you revved up. Remember, your body thinks that you are in danger and wants to keep you alert and awake. This is one of the reasons why people find it hard to fall asleep when under stress and insomnia is a common symptom of chronic stress.

You may fall asleep but because your body is still on high alert, your sleep is not restorative, and you wake up feeling just as tired as when you went to sleep. I know this problem all too well, feeling rested when I woke up despite getting plenty of sleep (often 10 hours or more) each night. This was especially eye-opening for me and prompted me to find strategies to calm my mind and body before bed.

Hair, Skin, and Nails

When the body perceives that you are in danger, its blood supply, oxygen, nutrients and energy are diverted to the most essential organs and processes that will save your life. Unfortunately, the health of your hair, skin, and nails is considered by the body to be non-essential processes. They are not going to make or break your survival and are often the last things to get the necessary attention. Therefore, stress can contribute to hair loss, skin disorders like acne, eczema and psoriasis, and brittle nails. The best way to get your hair, skin, and nails to thrive is to get your body back into the green zone. 


Have you heard of the brain-gut connection? You experience it when you feel butterflies in your stomach when you’re nervous or excited. So, it’s no surprise that our digestive system is impacted by stress. When we are in the red zone, the natural rhythmic contractions that move food through the gut are disturbed. Food moves slower through the digestive tract and affects the body’s ability to digest and absorb nutrients.

This can lead to disorders like IBS, acid reflux and changes to gut bacteria. With all the new information we are learning about the impact of gut health on our overall health (affecting immunity, inflammation, mental health and more), it’s easy to see how stress can have a domino effect on our wellbeing. 

How to Reduce Chronic Stress

Stress is an unavoidable part of life, but of course there are many things we can do to reduce the negative impact of stress in our lives and on our health.

The goal is to get out of the red zone (the constant fight or flight stress response) and back into the green zone where our parasympathetic nervous system can do its job – conserving energy, resting and replenishing.

Out of the Red Zone

To downshift the sympathetic nervous system (SNS) and get out of the red zone, we basically need to calm down (DUH! you’re probably thinking)! I know this is much easier said than done. But if the body feels it is in danger, it will keep activating the SNS and the stress response will continue.

One thing we must do is shift our perspective of the pressures we face in our daily lives.

I have a friend that very rarely ever gets stressed. I’m the opposite and am prone to worrying over the smallest things. For her, when a potential challenge comes up, like a project deadline, it doesn’t faze her. She just doesn’t interpret it in a way that causes panic or stress. It’s a pretty amazing skill and one that we all need. 

We have to work on reframing our thoughts about stress. Try to view stressful situations as challenges that you can control and master, rather than insurmountable threats. This will go a long way toward calming you down and reducing stress.

Another thing to consider is reducing caffeine. I know the coffee drinkers out there don’t want to hear this! I’m right there with you, I used to live on coffee too! But the problem with caffeine is that it increases adrenaline, the hormone that is released during the stress response. It keeps you revved up and energized, and it makes it harder to come back down and return to that state of rest and relaxation.

 It can be hard to make the transition to drinking less caffeine, but experiment with it and see how you feel. Try drinking decaf coffee (or half decaf/half regular) or herbal teas as a replacement. 

Into the Green Zone

This may sound unbelievable, but the best way to activate the parasympathetic nervous system (PNS) and return to the green zone is through breathing. Specifically, diaphragmatic breathing.

Diaphragmatic breathing, also called belly breathing or deep breathing, is a technique that engages the diaphragm and involves long, slow exhalation. You know that you are breathing from your diaphragm when your stomach moves up and down as you breathe in and out. This type of breathing actives the PNS by communicating to the body via the nervous system that it is safe.

For most people, this type of breathing doesn’t come naturally because we’re used to the short, shallow breathing from the chest that results from stress. It’s important to incorporate diaphragmatic breathing whenever you can to remind the body that it can relax. You can set a daily reminder or incorporate restorative, breath-focused practices into your routine, like yoga, tai chi, meditation and other forms of breathwork.

Get Your Nutrients

Keeping the body nourished with the vitamins and minerals it needs to regulate the nervous system and the stress response is important. Essential nutrients help regulate stress hormones that signal either danger or safety, neurotransmitters that allow for communication across the body, and the nervous system as a whole. Some of the key nutrients to include in your diet are B vitamins, vitamin C, calcium and magnesium.

Many herbs and adaptogens have also been promoted as effective stress relievers. Some of the most commonly used natural supplements for stress reduction are ashwagandha, chamomile, lavender, lemon balm, and holy basil, among many others.

Even though we tend to downplay it, stress has become a serious problem. Especially in our culture where we’re constantly busy and on the go. In the past, stress looked like a wild animal in the woods, but today’s stress has taken on a new form. It’s more psychological in nature and can be hard to escape. As a result, our bodies are constantly in fight or flight mode, responding to these daily stressors, with little opportunity for rest or recovery. This not only takes a toll on our mind, but our body as well. It leads to poor health outcomes like a weakened immune system and can potentially lead to chronic illness.

Fortunately, there is a lot we can do to calm our bodies and minds and get out of the red zone and into the green zone, where the body can do what it needs to do to keep us healthy.

So tell me, are you living in the red zone? How has stress been affecting you? Let me know by leaving a comment below!


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