How Does The Body's Stress Response System Work?
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Stress is often considered wholly negative but may be a positive or helpful force. In some cases, it's an essential component of human survival. Stress is defined by the National Institute of Mental Health as the brain's response to any demand or change. It can help humans escape threats and defend themselves. However, when stress becomes prolonged, it can have health consequences.
Each individual processes stress differently. Some people thrive under pressure, and others experience significant distress that interferes with their daily lives. How much stress you experience regularly can depend on external and internal factors, as well as your brain's unique makeup and your past experiences. Understanding how the body's stress response system functions may help you recognize the difference between healthy and unhealthy stress when they occur.
About the stress response system
The stress response system, also known as the fight or flight response, involves the sympathetic nervous system and the autonomic nervous system. When we encounter stress, the hypothalamus signals the pituitary gland to release corticotropin-releasing hormone, which then prompts the adrenal glands to produce stress hormones. This coordinated effort by the sympathetic nervous system and the autonomic nervous system helps prepare the body to respond to stress, but managing stress is essential to maintain balance and well-being.
Which part of the brain activates the stress response?
The stress response system is an integral part of the brain. The part of the brain called the amygdala is responsible for processing and controlling emotions, including detecting potential dangers that can produce stress. Much of what the brain deems as threatening is based on past experiences and is controlled by a part of the brain called the hippocampus.
The stress response itself is activated by a part of the brain called the hypothalamus. This primitive region of the brain sends a signal for the body to prepare for the fight-flight-freeze response. This signal arrives at the adrenal and pituitary glands, which push the rest of the body into action by releasing significant amounts of stress hormones, including adrenaline, norepinephrine, and cortisol.
These parts of the brain work together in fractions of a second to activate the stress response. While the stress response is often activated in situations involving real danger or urgency, it can also be initiated by situations or places that the brain associates with past negative experiences that may not be dangerous.
Chronic stress responses can cause these parts of the brain to become reactive. This reaction may also lead to the amygdala constantly firing, prompting the hippocampus to interpret situations as dangerous when they are benign. This abnormal activity can be seen in the brain scans of people with panic disorder or post-traumatic stress disorder (PTSD).
How the body's stress response system works
The body's stress response is also known as the fight-flight-freeze response. When the hypothalamus sounds an alarm, many changes are initiated throughout the body to help you face a threat or act with urgency. These changes happen almost instantly in a domino effect, often without your awareness. The following systems are involved in the process.
Cardiovascular system
The cardiovascular system involves your heart and lungs. These organs work together to deliver blood and oxygen to your other organs. When the stress response is activated, the cardiovascular system temporarily boosts your ability to fight against or flee from an enemy. The adrenaline and cortisol pumping through your blood speed up your heart rate and blood pressure, affording you a short-lived, intense increase in energy.
Since blood and oxygen are jettisoned to areas of the body most needed in a crisis, you may notice your hands or feet become cold when stressed. You may also notice that your breathing becomes faster and shallower. Hyperventilation can lead to light-headedness or dizziness if it continues for a prolonged period.
Muscular system
People living with chronic stress often report tense muscles in the neck and back. During the stress response, muscles all over the body tense up in preparation to fight or run away. When you feel acute stress, you may notice your jaw clench or your hands ball into fists. These changes may safeguard your muscles from injury and allow you peak strength to defend yourself, if necessary.
Digestive system
When the stress system is activated, your digestive system slows so your body can preserve as much energy as possible. Additionally, when your body is acutely stressed, your liver ramps up glucose production in the bloodstream.
Immune system
The immune system is temporarily boosted during short-term situations of acute stress. However, if the body faces chronic stress, the immune system becomes weaker under strain. This process causes those experiencing long-term stress to have a higher chance of becoming sick.
Other physical changes
The acute stress response may cause other secondary changes. If you glimpse yourself in the mirror while experiencing the fight-flight-or-freeze response, you may notice that your skin is pale, waxy, or flushed, and your pupils are dilated.
Mental processes
The stress response also affects your mood, attention, and thinking processes. Cortisol and norepinephrine sharpen your focus, sometimes to the point of "tunnel vision." You may feel more aggressive or "keyed-up" than usual. If you experience chronic stress, this effect can lead to irritability, anxiety disorders, and symptoms of depression. Long-term stress can also cause social withdrawal and anxiety.
Some people, including those who have experienced trauma, may dissociate during an acute episode of stress and feel detached from reality. You might feel paralyzed with fear or not know what to say. This response is a potential symptom of PTSD.
The acute stress response is designed to operate only for a short period. A healthy hypothalamus ceases the process once the danger is no longer detected. However, this system can get stuck in the "on" position for a few reasons.
Negative ramifications of chronic stress
Over time, chronic stress can adversely impact the heart and vascular system. If your heart rate and blood pressure are constantly elevated more than at a healthy level, it can wear down your cardiovascular system. This wear and tear can increase your risk of stroke or heart attack. Stress may also lower your mood and energy level.
Systems of acute stress, including rapid heart rate and shallow breathing, can convince a person that a health problem is occurring, which might lead to panic attacks. In addition, you may experience headaches, muscle pains, or indigestion from stress.
To combat these symptoms, some people adopt maladaptive coping behaviors. These behaviors may cause short-term relief but can be ineffective and unhealthy in the long term. Examples of unhealthy coping behaviors include binge eating, substance use, and avoidance.
How to lower stress
Not all sources of stress can be eliminated, but there are ways to reduce the impact of the stress system on your body and lower chronic stress, including the following.
Prioritize rest and relaxation
If possible, make regular time for relaxation and recuperation. Carving out regular time in your schedule to recuperate during periods of heavy external stress may be essential for minimizing its impact on the body and mind. Rest can mean prioritizing self-care and ensuring you get enough sleep every night. It could also mean cutting out social media or taking a break from stressful relationships.
Cut out stimulants
Stimulants can incite chronic stress in the body. The occasional cup of coffee might not cause this response, but you might have heightened stress levels if you depend on caffeine to get through your day. Caffeine raises cortisol levels substantially. If you feel you can't function without a steady stream of coffee throughout the day, speak to your doctor about alternatives.
Speak to a counselor
There are ways to cope with chronic stress, including therapy with a qualified professional experienced in helping people manage chronic stress. A therapist can use cognitive-behavioral therapy (CBT) and other therapeutic modalities to teach you techniques for managing your stress level. You may learn to recognize how your thinking patterns can contribute to increased stress levels and start to restructure your self-beliefs.
If you're stressed due to a busy schedule and can't find time for therapy, you might also benefit from an alternative type of counseling. With the rise of online therapy platforms like BetterHelp, convenient and flexible therapy may feel more manageable. In addition, online therapy is often more affordable than in-person therapy without insurance and as effective as in-person therapy for treating stress-related disorders like PTSD, anxiety, and social anxiety.
You can speak to a counselor via phone, online chat, and video chat. If you are seeking extra support between sessions, you can text your counselor anytime for support, and they can return your message as soon as possible.
Takeaway
What are the 4 components of the stress response system?
When the body perceives a threat, it coordinates a response between the HPA axis, the sympathetic nervous system (SNS), the parasympathetic nervous system (PNS), and the adrenal cortex.
- The HPA Axis: The hypothalamic–pituitary–adrenal (HPA) axis is a neuroendocrine system that controls reactions to stress and controls other processes such as digestion and immune responses.
- The Sympathetic Nervous System (SNS): The SNS plays an important role responding to dangerous or stressful situations by performing many functions you don’t have to think about controlling. This includes your heart rate, blood pressure, and digestion, among other functions. In other words, it controls the body’s fight-or-flight response.
- The Parasympathetic Nervous System (PNS): The PNS is the partner of the sympathetic nervous system. It is a network of nerves that activates the relaxation response to calm your body after periods of stress or danger.
- The Adrenal Cortex: The cortex is the outer part of your adrenal gland that releases important hormones that support well-being, including the hormone cortisol, which is commonly referred to as the “stress hormone,” and adrenaline.
What is your stress system called?
The body's stress response system is the product of neural pathways called the autonomic nervous system (ANS). The stress response, or fight-or-flight response, is typically triggered when a person is faced with a dangerous or stressful event. The nervous system performs key functions without requiring you to think about them –such as increasing your heart rate and blood pressure to motivate you to react and relaxing your body after the stressor or danger has passed.
What is the purpose of our stress response system?
The stress response system can help you avoid danger and provide energy to push through short-term obstacles. In the short term, these various functions of your nervous system help you cope with the situation or task at hand and build resiliency, confidence, and strength.
What is an example of a stress response?
Imagine a person is riding an electric scooter on a city road with one hand on the handlebars and the other hand feeling the rush of cool air. Suddenly, the person sees a giant pothole a few feet ahead. A sudden burst of fear surges in them and the stress response triggers their heartrate to increase, their pupils to dilate, and their hormones to surge. Instinctively, the person brings their other hand down to the handlebars. They are then able to hold on tight, navigate around the pothole, and continue on safely. Stress enabled the person to handle the stressful situation and meet the challenge.
What is the major system that controls the stress response?
The nervous system is the major system that controls the body’s stress response. It is comprised of two main parts: the central nervous system and the peripheral nervous system. They work together to send and receive signals that tell your body what to do, such as a stress reaction.
What does the stress response begin with?
The stress response begins with your hypothalamus, a structure deep within your brain. The hypothalamus is the main link between the endocrine and nervous systems, and helps keep the body balanced. It reacts to messages and signals to manage important functions such as your body temperature, blood pressure, and mood. When you feel stressed, the hypothalamus might react by causing elevated blood pressure and sending signals to your pituitary gland to secrete stress hormones such as corticotropin-releasing hormone (CRH).
What are the two main systems involved in the stress response?
The two main systems involved in the stress response are the central nervous system and the peripheral nervous system.
What are the negative effects of stress?
For many people, chronic stress leads to issues with the heart and vascular system. If you frequently have a rapid heart rate and high blood pressure, it can wear down your cardiovascular system. This wear and tear can increase your risk of stroke or heart attack. Stress may also lower your mood and energy level.
Systems of acute stress, including rapid heart rate and shallow breathing, can convince a person that a health problem is occurring, which might lead to panic attacks. In addition, you may experience headaches, muscle pains, or indigestion from stress.
Not all sources of stress can be eliminated, but there are ways to reduce the impact of the stress system on your body and lower chronic stress, including the following. Stress management techniques such as prioritizing rest, engaging in activities you enjoy, cutting out stimulants such as coffee and alcohol for blood pressure control, and speaking with a licensed mental health professional about how stress affects your life can all be beneficial.
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