How Stress Affects the Body—And What To Do About It
Health & Wellness
You may not even fully realise how stress manifests within you each day. Here, experts and researchers alike detail the effects of stress on the body and offer ways you can try to reduce it.
Stress—which is defined as "any type of change that causes physical, emotional or physiological strain", per the World Health Organization—can manifest in the body in many different ways.
"Stress is anything real, perceived or anticipated that disrupts homoeostatic balance and the stress response is what the body does to deal with stress and re-establish homoeostasis", said Layla Banihashemi, PhD, neuroscientist, assistant professor of psychiatry at the University of Pittsburgh. For context, homoeostasis is a self-regulating process that allows an organism, in this instance, you, to maintain internal stability while adapting to changing external conditions.
But, how does stress affect the body, exactly? Short-term changes, such as developing a rapid heartbeat or sweaty palms can occur upon the onset of stress. Long-term outcomes that are associated with chronic stress include an increased risk of heart disease and decreased immune function, for example.
Physiological Effects of Stress on the Body
Every person has a stress response system that is unique to them. Think of this system as a collection of responses that are designed to keep your body operating within a certain range of temperatures, blood pressure level and pain, said Shannon Peake, research assistant professor at the Center for Translational Neuroscience at the University of Oregon.
What Is the Stress Response System?
Your stress response system is designed to keep you operating within this range, also referred to as homoeostasis, Peake said. Whenever the body gets out of this range, the stress response system takes over, known as allostasis, to "dynamically manage what it needs to stay in the right range", Peake said.
The stress response system can be broken up into two divisions: the autonomic nervous system, or ANS, and the sympathetic nervous system, or SNS, Peake said.
The autonomic nervous system has a parasympathetic division known as "rest and digest" and a sympathetic division, more commonly referred to as "flight or fight", Banihashemi said.
The parasympathetic nervous system calms your body down after a threat, emergency or exercise, Peake explained. Additionally, "It restores functions that were put on hold during stress, like eating, digesting food and urination", he said.
The sympathetic nervous system can be further broken down into two reactions: the fast adrenaline response (which takes two to three minutes) and the cortisol response (somewhat slower and takes approximately 10 to 15 minutes), Peake said.
The cortisol response is activated by the hypothalamic-pituitary-adrenal, or HPA, axis. When you experience a threat, the hypothalamus sends a message to the pituitary gland in your brain, which sends a message to the adrenal glands in the kidneys, which then release cortisol into your bloodstream.
The HPA axis ultimately leads to the release of glucocorticoids, steroid hormones that play a pivotal role in the body's metabolism of glucose, protein and fat. They also provide energy for the "flight or fight" response. Cortisol is the essential glucocorticoid in your body, affecting the heart, liver, immune cells and muscles in a process that can take many minutes to an hour, Banihashemi said.
How Stress Presents Itself in the Body
When you perceive a threat, your body produces cortisol (approximately 15 minutes after the onset of a stressor), allowing your body to maintain its readiness for action as the adrenaline tapers off, Peake said.
It usually takes about 30 to 45 minutes for cortisol production to peak and it will begin to slowly taper off once the stressor is gone, which is contingent upon how long it takes you to calm down, Peake explained. Similar to adrenaline, cortisol increases both blood pressure and heart rate and it also triggers the release of sugar from the liver for energy, he said. Additionally, inflammatory responses and digestion (bodily functions that require energy that is not needed immediately) will be reduced in order to conserve energy.
Types of Stress
In addition to understanding your individual stress response system, it's also important to understand the different types of stress.
1. Acute Stress
Acute stress can be thought of as something that happens once and manifests as one (or a few) of the physiological effects described above. An example of acute stress would be locking yourself out of your home or sleeping through your alarm and missing an event on your calendar.
"We're well-equipped to deal with acute stressors", Banihashemi said, adding that the stress response helps you deal with stress in order to aid in your survival and then transition back to a state of rest.
"When your body is exposed to acute stress, part of your stress response system is to deal with the immediate effect. But, another part of your stress response system is to use that event to prepare for that event in the future", Peake said.
For example, exercising is a stressor and the body records what it did to get through that stressor (a workout). Over time, your muscles get stronger and your blood flow and energy usage both become more efficient.
2. Chronic Stress
Conversely, chronic stress can be thought of as stress that's continuous. If you're experiencing chronic stress, your body stays on high alert and in a high metabolic function, which can lead to high blood pressure, heart disease, diabetes, anxiety, depression and lowered immune function, Peake explained.
3. Psychological and Social Stress
You can also experience psychological and social stressors like deadlines, financial concerns and relationship issues. While these may start as acute stressors, psychological and social stressors can become chronic stressors. When this happens, your body turns on stress responses meant to address acute stressors, "which can ultimately be maladaptive and damaging to one's health", Banihashemi said.
The problem with stress, according to Peake, occurs when the stressors become unmanageable—which your stress response system also tracks. Eventually, your body and mind will begin to think that the stressors won't stop and are out of your control, leading to learnt helplessness or you'll start to develop unhealthy coping mechanisms, Peake said. Examples of maladaptive coping mechanisms are disengagement, avoidance and emotional suppression.
In short, stress is inevitable. But, how you manage it makes all the difference when it comes to your well-being.
How To Prevent Stress
Peake explained that most people experience social stress in relation to one's job or relationships, for example, and exercise can be helpful in reducing those stress levels.
"Exercise is a way of reducing stress because it starts to change the way your body reacts to stress. It becomes more manageable", he said.
A systematic review and meta-analysis, found in a 2022 issue of the journal Nature, found that just one exercise session ranging from 30 to 60 minutes, on average, can lower systolic blood pressure, diastolic blood pressure and mean blood pressure in younger, healthy adults.
Banihashemi also recommended practising mindful walking, where you take deep breaths. This is important because long exhalations can shift your system from being in a sympathetic state to a parasympathetic state. Pay attention to the sensations throughout your body and enjoy the nature surrounding you, Banihashemi suggested.
(Related: How Exactly Does Exercise Reduce Stress?)
2. Deep Breathing, Meditation and Mindfulness
You only need a few minutes to reap the benefits of deep breathing and meditation. There's a connection between your mind and body, specifically, the enteric system—which consists of the gut, heart and peripheral nerves, Peake explained. Deep breathing can help regulate the enteric system by triggering the parasympathetic nervous system to calm things down.
Deep breathing, meditation and mindfulness are also tools to reduce and prevent psychological stress. Additionally, problem-solving whatever the stressor is and working on how you perceive the stressor can help alleviate stress, Peake said.
A 2018 experimental study found that sleep-deprived people had higher cortisol and self-reported stress levels than those who weren't sleep-deprived. Sleep helps you function optimally—and it can also reduce stress by keeping your HPA axis under control as opposed to an increase in HPA axis activity caused by sleep deprivation. A lack of sleep prevents your body from repairing properly, and, as a result, it's unable to optimally handle the stressors of the next day, Peake said. According to the Centers for Disease Control and Prevention (CDC), adults should get a minimum of seven hours of sleep each night.
4. Social Support
Another way to reduce stress is by having social support from friends, family, a partner and other loved ones, who can help you get through stressful times.
According to a 2017 meta-analysis on the correlation between social support and mental health, social support reduces the adverse effects of mental stress in a handful of ways. That's because leaning on someone enables you to feel supported through difficult moments and satisfies other emotional attention needs.
The Bottom Line
You may not be able to avoid stress entirely but understanding how stress impacts your body in the short and long term, as well as knowing methods to prevent and manage your stress, can be hugely beneficial for your overall well-being. The next time you're feeling stressed, consider taking a few deep breaths to reset, move your body or reach out to a loved one for emotional support.
Words by Tamara Pridgett