Stress exerts numerous metabolic responses and affects many systems of the body, including musculoskeletal, respiratory, cardiovascular, gastrointestinal, nervous, reproductive, and endocrine systems.
While acute stress is adaptive in nature, episodic and chronic stress can lead to various health problems. Discover exactly what stress can do to the body including the main physical symptoms of stress.
Review of Stress
Stress is considered a natural, biological response to life experiences and major changes. Nearly everyone experiences stress throughout life, though different situations affect people’s stress responses uniquely. A divorce might be perceived as extremely stressful to one, while viewed as a bright new opening to another. Furthermore, the degree of the stress response is also different for everyone.
The body possesses an innate stress response in order to quite literally make survival more likely. At the onset of the perception of stress, the body secretes hormones that signal the autonomic nervous system to go into fight or flight mode. The hypothalamus triggers the adrenal glands to secrete extra cortisol, which increases heart rate and blood pressure. It also readies skeletal and heart muscles further by initiating the secretion of glucose into the blood.
In the short term, this is a positive, adaptive mechanism that helps people stay alert, motivated, and prepared to fend or fight danger. It includes symptoms of racing heart, increased blood pressure, muscle tension or readiness, and occasionally nausea, vomiting, or diarrhea. After the stressor is removed, the body should return to baseline.
In the long run, the continual activation of the stress response greatly wears and tires the body. Physical symptoms of long-term stress include:
• Increased aches and pains
• Chest pain
• Frequent racing heart
• Headaches, vertigo, or migraines
• High blood pressure
• Muscle tension or jaw locking
• Stomach and digestive problems
• Lowered sex drive and/or fertility
• Weakened or overly increased immune system (autoimmunity)
Mental and emotional symptoms of long-term stress:
• Anxiety and depression
• Irritability and mood swings
• Panic attacks
• Risky behaviors like gambling, excessive drinking, or doing drugs
• Over or undereating
• Feeling hopeless or suicide ideation
• Low motivation to do daily activities
• Trouble maintaining jobs or responsibilities
Now take a look at exactly how stress can affect major bodily systems.
How Does Stress Affect the Body?
Within each bodily system, acute and chronic stress may impact it differently. Interestingly, chronic stress is known to affect male cardiovascular systems and female endocrine and reproductive systems most.
Cardiovascular System
Acute stress - such as meeting a deadline, running from danger, or slamming the brakes to avoid a car accident - causes increased contractions and heart rate via the signals of cortisol, adrenaline, and noradrenaline. Furthermore, blood vessels that supply oxygen and nutrients to the heart and muscles dilate or widen in order to be able to pump more blood to those areas. In layman's terms, this refers to increased blood pressure.
Chronic stress is perhaps best known to induce cardiovascular complications. Even some health professionals believe stress is a bigger risk factor for heart disease than poor diet or exercise habits!
The consistent increase in heart rate, blood pressure, and release of stress hormones greatly increase the risk for hypertension (high blood pressure), heart attack, and stroke. Persistent stress can also lead to systemic inflammation, especially within coronary arteries closely related to the risk of a heart attack. Some research even shows that chronic stress contributes to increased cholesterol levels as well.
Interestingly, healthy estrogen levels allow women to respond better to stress and reduce their risk of heart disease. Thus, postmenopausal women and those with PCOS, endometriosis, and other similar conditions likely have a decreased tolerance for chronic stress due to an imbalance in estrogen levels.
Endocrine System
The main driver of the endocrine stress response revolves around the hypothalamic-pituitary-adrenal axis (HPA axis). Its main job is to increase the production of steroid hormones called glucocorticoids, namely cortisol, also known as the 'stress hormone.'
During high-stress situations, the hypothalamus signals the pituitary to produce a corticotropin-releasing hormone (CRH) that then triggers the pituitary gland to secrete adrenocorticotropic hormone (ACTH). This second hormone then stimulates the adrenals to increase the production of cortisol.
Cortisol's main purpose is to increase the amount of available fuel by mobilizing glucose and fatty acids from the liver. In healthy, balanced individuals, cortisol is highest in the morning, relatively stable throughout the day and low at night to help prepare for rest and sleep. During acute stress, cortisol climbs and then returns to baseline when the stressor is removed.
However, cortisol also plays roles in immunity and inflammation. Chronic stress can ultimately disrupt the communication between the immune system and the HPA axis. This disruption is linked to future development of physical and mental health struggles like adrenal fatigue, hypothyroidism, other autoimmune issues, and depression.
Gastrointestinal System
Unfortunately, chronic stress can negatively affect multiple parts of the GI system from the stomach to the esophagus to the colon. This is because the gut contains millions of neurons that are in constant communication with the brain. This phenomenon is often referred to as the enteric nervous system and often causes one to feel 'butterflies' in the stomach.
However, like the endocrine system, chronic stress can disrupt the enteric nervous system and its communication with the brain. This dysfunction may cause symptoms of stomach pain or cramps, bloating, diarrhea or constipation.
Very relevant today, research also suggests that ongoing stress can literally alter the gut microbiome. The microbiome is home to thousands of millions of bacteria that help regulate emotions, thinking patterns, disease risk and so much more.
Of note, significant early life stress can alter the development of the nervous system and stress responses. Such changes may also increase the risk for gut issues down the road.
Well known to many, chronic stress can affect appetite through an increase or decrease. More people struggle with overeating when stressed, sometimes called emotional eating. This may encourage pooper food choices that then aggravate the esophagus and worsen heartburn.
Finally, stress may affect how quickly food moves through the body, leading to diarrhea in some and constipation in others. It also makes bloating and any other stomach pains generally worse. Occasionally, severe stress causes muscle spasms of the bowel that are very painful.
Because stress affects how long food remains within the system, it also has implications for nutrient extraction. In some cases, food may pass through too quickly to obtain all the necessary nutrients. In others, the gut and colon barrier weakens and allows food and other particles to pass through to the blood, spurring autoimmune reactions.
Musculoskeletal System
The sudden onset of stress causes muscles to tense up all at once and then release the tension as the stress passes. This is its way of guarding against injury and pain.
Chronic stress causes muscles to remain in a tensed, guarded state indefinitely. When this happens, other stress-related disorders are more easily triggered. For example, chronic muscle tension of the neck, shoulders, and head are implicated in tension headaches and migraines. In general, chronic lower back pain is also associated with chronic stress.
Nervous System
The nervous system is composed of numerous divisions, including the central division of the brain and spinal cord. It also includes the peripheral division of the autonomic and somatic systems.
The autonomic system is further divided into the sympathetic and parasympathetic nervous systems:
• The sympathetic nervous system (SNS) responds when the body is stressed. It's also responsible for the fight or flight response, where the body increases fuel sources to help avoid danger. Ultimately, the SNS tells the adrenals to release adrenaline and cortisol to allow the heart to beat faster, breathe harder, dilate blood vessels and secrete glucose into the bloodstream.
• The parasympathetic nervous system (PNS) counteracts the SNS and helps return the body back to baseline. However, over-activity of the PNS can also add stress reactions by promoting too much lung constriction or compromising blood circulation.
Frequent autonomic triggering tires the body but the continuous activation of the SNS typically manifests as negative symptoms elsewhere in the body, like the reproductive system.
Reproductive System
Generally speaking, chronic stress downregulates the least important functions of the body. While reproduction is vital in the collective sense, it’s hardly as important as breathing, pumping blood, and providing energy when the body perceives a constant state of danger.
Thus, it's typical for females to stop menstruating when under a large amount of stress. Not only this but stress can:
• Change the length of cycles
• Make cycles more painful
• Increase the risk of developing PCOS or endometriosis
• Worsen symptoms in menopausal women
For all sexes, chronic stress can greatly reduce libido, as the body reduces unnecessary signals and increases signals that will help the human survive first and foremost. In addition, chronic stress can also negatively impact sperm production, maturation, and viability.
Respiratory System
In the short term, severe acute stress has been known to trigger asthma and panic attacks or hyperventilation.
Acute and chronic stress can present with respiratory symptoms like shortness of breath or rapid breathing as lung airways constrict. This effect is greatly exacerbated and more dangerous for those with preexisting respiratory problems like COPD.
In Summary
Short-term stress is an adaptive response intended to help someone survive through the direst situations. This acute response increases heart rate and blood pressure and harnesses extra glucose for the heart, muscles, and other working organs, and then returns to baseline hormonal levels. This causes few if any health problems.
Conversely, the repeated activation of the stress response can lead to long-term stress, which chronically raises cortisol levels and affects most bodily systems negatively over time. Chronic stress triggers a slew of physical, mental, and emotional symptoms that should not be ignored.
While most of the symptoms are troublesome, seek medical assistance immediately if:
• Fertility is affected
• You have trouble maintaining responsibilities
• Panic attacks are frequent
• You start struggling with suicide ideation.
These are signs that the body needs intervention because chronic stress levels are too great to handle alone. No need to suffer as various stress-reducing techniques can help you cope!
References:
Pietrangelo A. The Effects of Stress on Your Body. Healthline. Updated March 29, 2020. https://www.healthline.com/health/stress/effects-on-body#Central-nervous-and-endocrine-systems.
Stress Effects on the Body. American Psychological Association. Published November 1, 2018. https://www.apa.org/topics/stress/body.
Stress: Signs, Symptoms, Management & Prevention. Cleveland Clinic. Reviewed January 28, 2021. https://my.clevelandclinic.org/health/articles/11874-stress.
