How Stress Affects the Body: Physiological Affects Explained

For thousands of years, people have meditated to discover the stillness and silence that rests within, as a way to move beyond the daily stressors of life and experience greater clarity, regulate mood and emotions, improve judgement and confidence, and live lives of deeper fulfillment. Meditation is the solution, the antidote to stress.

How Stress Affects the Body Stress is defined as how one responds when needs or expectations are not met. Human beings experience this phenomena 8 to 15 times a day. Assuming our typical 8 hours of sleep, that’s an unmet need every one to two hours. But it’s what we do with it, how we respond to our unmet needs - what we think, the words we speak, and how we react to each other and our unmet needs - that determine the fabric of our life.

Stress is universal. Yet the individual ways each of us responds to having our needs met, and how we respond when they aren't met, become this unique mosaic we call our reality.

The most recent scientific data now points to the fact that not all stress is necessarily bad for us, that it may even add to our lives. Stress has now been proven to enhance performance by focusing us and pushing us forward in the direction of our goals, and with this stress-driven motivation comes increased productivity and greater satisfaction. Severe stress - such as in the aftermath of trauma - has been been credited with birthing Aha! moments, reinforcing our relationships and elevating journeys of personal development. It’s even been confirmed that stress has restorative properties that can increase health and rejuvenate cells after the initial ordeal. But the long-term implications of stress are all based on our perception of it. As the familiar phrase reminds us, “stress is in the eye of the beholder.”

An eight-year study heralded by Dr. Richard J. Davidson at the University of Wisconsin-Madison studied perception of stress and its impact on mortality. In year one, more than 25,000 adults were asked to rate their stress levels over the past year and rank how much they believed this stress influenced their health. Over the next eight years, public records were used to record the death of any subject. The subjects who (1) self-reported high levels of stress and (2) believed stress had a large impact on their health, had a 43 percent increased risk of death. However, the test subjects who self-reported a lot of stress but did not interpret its effects as negative, had the fewest deaths over the time span.

Over the past two millennia, humans have evolved with a deeply ingrained survival instinct known as the fight-or-flight response. This is our most primal reaction to perceived danger—a biological safeguard that activates when our sense of physical safety is threatened. In moments of perceived danger, our brains instinctively push us to make a snap decision: confront the threat or flee from it.

Mature woman thoughtfully working through brain fog due to chronic stress.

This ancient survival mechanism is driven by the limbic system, the part of the brain responsible for emotion, memory, behavior, and even smell. The limbic system signals the autonomic nervous system, which quietly orchestrates essential bodily functions behind the scenes—like blinking, swallowing, or maintaining internal balance. It operates like a built-in autopilot for survival, regulating our hormones and metabolism without conscious input.

In modern life, however, the threats we face are rarely life-or-death. Still, we encounter daily challenges—disappointments, unmet expectations, and emotional friction. When our needs go unmet, our nervous system may still interpret the moment as a threat, especially if we respond automatically rather than consciously. Acting on reflex rather than with reflection, puts us in “survival mode,” activating those primitive systems and chemical responses we inherited from our ancestors.The stress hormone cortisol is secreted by the adrenal glands to maintain the body’s equilibrium, peaking each morning and ebbing in the evening. It’s primary functions are to increase blood sugar; reduce blood pressure; suppress the immune system; decrease bone formation; and aid the metabolism of fat, protein and carbohydrates. Cortisol is called “the stress hormone” because it’s secreted in its highest levels during the body’s fight-or-flight biological response to stress. It functions to: lessen sensitivity to pain, deliver in-the-moment surges of energy, amplify memory function, and support homeostasis in the body.

CT scan of the brain as reviewed by a neurologist.

Yet these tremendous benefits also come with a hitch. There’s no cortisol “off” switch, so we may hold on to those surges for hours after a fight-or-flight moment. Prolonged levels of cortisol in the bloodstream caused by emotional stressors have been shown to have negative effects:

• Decreased bone density

• Higher blood pressure

• Lack of clarity

• Suppressed thyroid function

• Blood sugar imbalances such as hyperglycemia and diabetes

• Suppressed immunity and inflammatory responses

• Increased abdominal fat

Middle-aged woman experiences signs of chronic fatigue syndrome felt as exhaustion.

Increased levels of cortisol shrink the hippocampus, impacting memory formation, new brain development, and our ability to learn. Simultaneously, cortisol increases the size of our amygdala, keeping us in fear based learning mode. Stressful life events impact the brains of even healthy individuals, making them less capable of enduring subsequent stressful events by hindering their emotions and self-control.

A 2012 study commissioned by Emily Ansell of Yale University School of Medicine, interviewed 103 healthy subjects about traumatic stress and adverse life events. She observed across-the-board marked shrinkage in the medial prefrontal cortex, the anterior cingulate, and the insular — the parts of the brain responsible for personality expression, emotions, decision making, self-control, and goal achievement. And these parts of the brain shrank with every additional stressful life event a test subject had experienced. Ansell concluded that the accumulation of stressful life events may make it more challenging for these individuals to deal with future stress, particularly if the next demanding event requires effortful control, emotion regulation, or integrated social processing to overcome it. As we now know, the next “demanding” event, will indeed require those skills. 

One of the most potent benefits to destressifying is the suppression of cortisol so that the body’s functions can quickly return to normal following a stressful event. Our brains are dynamic and plastic and things can improve but only if stress is dealt with in a healthy manner. And right in your hands, you hold the key to dealing with stress in healthy ways.

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