The Effects of Chronic Stress on the Body
The Far Reaching Effects of Chronic Stress on the Body
While a certain amount of stress can be helpful in contributing to motivation and productivity, most of us realize that excessive amounts of stress, especially over long periods of time, can have negative effects on our health. Have you ever wondered if a given health condition may be worsened by stress? Read on to learn more about what we know when it comes to stress and our health.
Understanding the effects of the stress response:
Let's start be defining stress as a more generalized term: According to the National Institute of Mental Health, "stress is how the brain and body respond to any demand." When we think about stress more specifically, we can look to the teachings of Dr. Robert Sapolsky, a Stanford Professor who has spent decades studying the effects of stress on our health. Dr. Sapolsky explains the stress response as an evolutionary mechanism designed to respond to a threatening situation. For example, if you are running for your life, your body will release hormones like cortisol and adrenaline, which will temporarily increase heart rate, blood pressure and energy levels. At the same time, we will turn off processes in the body that we don't need during this time, like digestion, growth and reproduction. All of this together allows us to focus on getting away from the acute threat that we are facing. Ideally, these physiologic changes that help us deal with an acute stressor would return to baseline after the threat has passed; our blood pressure and heart rate would return to normal and our body could focus on digestion, growth and reproduction again. However, the problem arises when the stress response becomes chronic and these physiologic changes persist. In today’s world where we aren’t necessarily running away from threats, we are still perfectly capable of creating other forms of stress in everyday life. For example, we can induce states of psychological stress when we compare our car to that of our neighbor, or compare our appearance to friends on instagram. In this chronic activation of the stress response, it becomes clear how various health conditions may results when we stay in a physiologic state that favors acute survival over growth, repair and reproduction.
On a more physiologic level, it can be helpful to orient ourselves to the different parts of the nervous system involved in the stress response. This includes the autonomic nervous system (ANS), as well as the sympathetic and parasympathetic branches that make up the ANS. The ANS is the part of the nervous system that is somewhat "automatic" and [regulates physiologic processes such as heart rate, blood pressure, respiration, digestion and sexual arousal.The sympathetic nervous system is also referred to as the "fight or flight" branch of the ANS; this is the branch that is activated during stress resulting in elevation in heart rate and blood pressure, and the shutting down of digestion, growth, repair, and reproduction.
Overall, the stress response is advantageous when there is an acute threat and can even be helpful to prepare for events like giving a presentation or facing a short-term deadline at work. The negative effects of stress arise when stress is prolonged as it is for so many in the modern era of never ending tasks at home and work. Many of us live in a near constant state of “fight or flight” with ongoing activation of our sympathetic nervous system and the resulting physiologic changes discussed above. This can be due to stressful situations at home or work on a personal level, including physical stressors like illness, as well as psychological stressors like internal worry.
Internal worry and stress can come in many forms; one common form in today's world may be the result of excessive social media use. When we compare ourselves to others on instagram or facebook, we may feel like we are inadequate and not keeping up in multiple areas of our lives like work, family, or even our appearance. Perhaps your neighbor has a nicer car than you, or your friend's instagram photos look better than yours.
Social pressures in real life and online can certainly contribute to stress.
It addition to internal stressors on a personal level, we can also feel the effects of events on a global scale like famine and war in other parts of the world. With social media use, we have 24/7 access to news and current events and can feel like we are right there witnessing devastating events happening somewhere across the world.
With all of these triggers that pile up in day to day life from personal and global events, we can get stuck with the gas pedal on, and the nervous system in sympathetic overdrive. If the stress response is activated for too long, it can impair various systems in the body and have negative impacts on our health.
Let's take a closer look at some of the conditions that can be worsened by stress including anxiety, sleep disorders, muscle tension and chronic pain, migraines, hypertension, digestive disorders, autoimmune disease, low libido and infertility, and even asthma and allergies.
The Effects of Stress on the Nervous System: Anxiety and Mental Health Conditions:
An overactive stress response has been associated with mental health conditions including anxiety and depression as well as insomnia and sleep disorders.
Close to 30% of the population has experienced anxiety at one time or another during their lifetime What exactly is anxiety? Some theories propose that there is an impairment of vagus nerve activity in conditions like anxiety. The vagus nerve is involved in the parasympathetic or “rest and digest” branch of the nervous system. This is the branch of the nervous system that gets shut down during acute and chronic stress. If vagal nerve activity is impaired by chronic stress, this can lead to an imbalanced and inflexible nervous system that is unable to inhibit the overactive sympathetic response. In other words, we can get stuck in “fight or flight” and are unable to relax and recover.
In addition to the effects of current stress, It has even been shown that chronic stress early in life, including the prenatal period as well as during adolescence and teen years, can contribute to the likelihood of the development of anxiety and depression later in life. Another variable involves unpredictable stress: a recent animal study showed that exposure to unpredictable stress led to increased anxiety related behaviors.
The Effects of Stress on Sleep:
In addition to its effects on mental health, stress can also contribute to sleep disorders and insomnia. Up to 30% of adults report having disruptive sleep in a given year. It turns out that the autonomic nervous system plays a key role in sleep. While both the sympathetic and parasympathetic nervous system play a role in different stages of sleep, studies have shown that there may be an over-activation of the sympathetic nervous system in patients with insomnia.
The Effects of Stress on the Musculoskeletal System and Chronic Pain:
Pain, like stress, involves mechanisms by which our bodies try to adapt to our current environment in an effort to protect us. The problem arises when these mechanisms involving pain and stress become chronic and maladaptive.
Our current thinking is that pain can be explained by a biopsychosocial model. What this means is that pain is likely the result of a complex interactions between genetic factors and our environment that can lead to maladaptive changes in the body's regulatory systems. The end result of these changes is chronic pain.
Psychological stress is one environmental factor that can contribute to chronic pain.
The effects of psychological stress on pain syndromes can be explained by multiple potential mechanisms that alter pain signaling in the body. One of these mechanisms involves excessive muscle tension and micro-structural damage; many of us notice that we tense our muscles when we are under stress. Another mechanism involves changes in the hippocampus (a part of the brain involved in pain processing, learning and memory) that alter our ability to make new neurons and signaling pathways in the brain.
Stress and Migraine:
One common chronic pain condition that can be worsened by stress is migraine. In fact, migraine sufferers often list stress as a common trigger for attacks. There is evidence that stress can trigger migraines in those predisposed to this condition, and can also contribute to the condition becoming more chronic. While stress can be a trigger for migraine, the pain and suffering from this condition can contribute to stress. It can become cyclical, and any interruption to the cycle can be helpful.
Stress and Chronic Low Back Pain:
Chronic low back pain is another common chronic pain condition. There is evidence that stress can play a role in the development of low back pain and its persistence. One study looking at the relationship of stress and later onset of back pain found that psychological distress earlier in life doubled the risk of low back pain several years later. Another study concluded that psychological stress may play a role in the evolution of acute back pain into chronic back pain.
There is also an influence of stress on the cardiovascular system. The physiologic changes from stress cause constriction of blood vessels as well as elevation of heart rate, stress hormones (like cortisol) and blood pressure. These effects over time can contribute to a higher risk of hypertension and cardiac disease. Stress from diverse causes including external stressors as well as internal worries can have an effect; a few of these causes include stress from work situations, noise exposure, living in urban environments and stress from social isolation.
There is a connection called the gut-brain axis that describes the connection between gastrointestinal tract and the brain. Bi-directional communication exists, and we know that chronic stress can result in symptoms in the GI tract and contribute to conditions such as irritable bowel syndrome, reflux, and changes in appetite. Chronic stress can even affect nutrient absorption and weaken our intestinal barrier. Some other mechanisms by which ongoing stress can affect our gastrointestinal system include contributing to dysbiosis (an imbalance in our microbiome) and affecting gut motility (with resulting constipation or diarrhea).
Chronic stress can even change the communication between the HPA axis (hypothalamic-pituitary-adrenal) and the immune system. The HPA axis is the system in the body that controls the stress response and is responsible for secreting cortisol and other hormones. Cortisol in turn is important for helping to regulate immune function. Chronic stress can lead to immune dysregulation and may play a role in the onset and symptoms of autoimmune diseases. Autoimmune illnesses involve the loss of self-tolerance, meaning the body starts to see its own tissues as foreign and creates a maladaptive immune response. While there are multiple genetic and environmental influences that can contribute to autoimmune disease, stress can be one factor involved.
In men, we know that chronic stress can contribute to lower libido and erectile dysfunction. It can even affect fertility by decreasing sperm production and maturation. In women, excessive stress over prolonged periods of time can contribute to irregular menstrual cycles, decreased libido, and increased symptoms during menopause.
For those with asthma and COPD (chronic obstructive pulmonary disease), we know that stress can cause flares of these conditions. With asthma for example, there are several theories as to how stress can contribute to flares. One model theorizes that psychological stress increases the inflammatory response in the airways to irritants, allergens, and infections. Other theories discuss the role of psychological stress in more directly causing oxidative damage and inflammation in conditions like asthma.
In conditions such as hayfever, seasonal allergies, eczema (or atopic dermatitis), and other allergic diseases, chronic stress can play a role in the onset and exacerbations of symptoms. Stress can also make the symptoms harder to control with usual therapies. Through the physiological mechanisms activated with a chronic stress response, the balance of the immune system can be altered to favor an overall allergic inflammatory response.
The activation of the stress response and the resulting physiological changes can have profound effects on our bodies. The good news is that there are many tools that we can employ to help mitigate these effects but the first step is recognizing the potential connection between chronic stress and what we are experiencing. Counseling, social connection, exercise, adequate sleep, meditation, restorative yoga, mindfulness and breathing exercises can all be helpful. (would link to separate blog post on lifestyle interventions to help with chronic stress).
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