You’ve likely encountered the physical effects of stress at some point – sweaty palms, a racing heart, and shallow breathing. These sensations often accompany the overwhelming feeling that stress can bring. Stress is a fundamental part of our biology, tied to the “fight or flight” response that has contributed to our species’ survival. However, in the complex landscape of modern life, this innate response can pose challenges to our long-term well-being.
This article delves into the physiological aspects of stress, its impact on various bodily systems, and offers practical strategies for managing it.
Understanding the Physiology of Stress
Stress can be described as a state of imbalance or disrupted homeostasis within an organism. Essentially, we strive to maintain a stable and harmonious internal environment, but stressful events can throw this equilibrium off-kilter. The body’s stress response is regulated by the sympathetic nervous system. When faced with imminent danger, your body activates a series of physical and hormonal changes that prepare you to react. Some of these changes include:
- Increased blood pressure and heart rate.
- A surge in stress hormones like epinephrine, norepinephrine, and cortisol.
- Redirection of blood flow away from internal organs toward the muscles.
- Increased muscle tension.
- Suppression of immunity, digestion, and reproductive functions.
These physiological responses serve a protective function when confronting threats, as they mobilize the body’s resources to meet the demands of a dangerous or stressful situation. Unfortunately, when the source of stress is ongoing daily pressure, these responses can have a detrimental impact on your overall well-being. In such cases, the body’s stress response can end up causing more harm than the stressor itself, affecting various aspects of health.
Chronic Stress and Its Connection to Body Weight
For some individuals, chronic stress can be linked to higher body weight. Several factors contribute to this relationship. While certain stress hormones can reduce appetite, others can heighten it. Cortisol, in particular, tends to spike in the latter stages of the stress response and remains elevated during the recovery phase. This hormone stimulates hunger and a motivation to eat, as a means of replenishing calories lost while responding to a stressor. Chronic stress can also trigger the brain’s reward system, leading to cravings for highly palatable comfort foods, such as fast-digesting carbohydrates and fatty foods, which people may turn to for emotional relief rather than nutritional necessity.
Furthermore, cortisol can prompt increased fat storage, especially around the abdominal area. Visceral fat, the fat cells in the abdomen, is especially responsive to cortisol and tends to store more fat when exposed to it.
Chronic Stress and Digestive Function
Stress significantly inhibits digestion. Blood flow is diverted away from the digestive organs, digestive enzymes responsible for breaking down food decrease, and the muscular contractions of the intestines (peristalsis) are disrupted. This redirection of resources is advantageous when facing an immediate threat, but when stress becomes chronic, it disrupts the digestive system’s efficiency. Additionally, stress can lead to elevated markers of gastrointestinal inflammation and is associated with conditions like irritable bowel syndrome, ulcers, Crohn’s disease, and ulcerative colitis.
Chronic Stress and Mental Health
Prolonged stress can have a negative impact on mood, and high stress levels are linked to increased rates of depression and anxiety. Extended exposure to cortisol and other corticosteroids can contribute to feelings of anxiety and the development of depression. Elevated cortisol levels are often observed in individuals with major depression, and animals with high corticosteroid levels exhibit depressive symptoms such as poor sleep, changes in locomotion, reduced appetite, and low libido. Furthermore, individuals exposed to early-life stress are more likely to experience significant mental health challenges in adulthood.
Chronic Stress and Its Link to Disease
Inflammation is a natural part of the immune response to illness or injury, involving white blood cells, antibodies, and cytokines that defend compromised tissues. Like stress, this is beneficial in the short term. However, persistent inflammation can foster the development of most chronic diseases. Uncontrolled stress can incite or perpetuate systemic inflammation, and research indicates that stress is a common risk factor in 75 to 90% of modern diseases, including cardiovascular disease, diabetes, liver disease, Alzheimer’s disease, and cancer.
The Positive Aspects of Stress
While stress may appear inherently negative, it can also have positive effects. Stress can enhance cognition, motivation, memory, creativity, vigilance, and perseverance. Moreover, how we perceive a stressor significantly influences its impact on us. Viewing a stressor as a “challenge” rather than a “threat” results in better physical and psychological outcomes. Our attitudes and beliefs about stress, known as stress mindsets, can alter our behavioral and psychological responses to stress, ultimately affecting our long-term outcomes. For instance, a study examining perceived stress and depression in college students found that those with a higher perception of stress were more likely to experience depression.
To objectively assess the effect of mindset on the physiological stress response, researchers conducted an experiment involving a mock interview and measured two stress hormones: cortisol and dehydroepiandrosterone (DHEA). As previously mentioned, cortisol is associated with some of the negative effects of chronic stress, while DHEA has positive effects on health. Participants were randomly assigned to watch either a “stress is enhancing” or “stress is debilitating” video before their mock interviews. The “stress is enhancing” group exhibited a significantly greater increase in DHEA levels, which is linked to improved health outcomes in response to stress, compared to the “stress is debilitating” group.
Stress is an inevitable part of life. When left unmanaged, its physiological impact can be detrimental to health. However, your mindset can transform your stress response, allowing it to enhance creativity, motivation, and perseverance, ultimately making you more resilient in the face of future stressors.