Effects of Chronic Stress on Cortisol Levels

Chronic stress can profoundly alter how your body produces and regulates cortisol, the hormone responsible for managing your stress response. Over time, prolonged psychological, emotional, or physical stress may lead to a blunted cortisol response, leaving you with fatigue, difficulty concentrating, and a weakened ability to handle daily challenges. Dr. Jeff Matz at Via Nova Health helps patients understand these effects and supports strategies to restore healthy cortisol function. For more information, contact us or request an appointment online.

Most people know cortisol as “the stress hormone,”  the chemical your body releases when you’re under pressure. It’s supposed to spike when you need it, then settle back down. But what happens when your body has been under stress for so long that this system starts to break down?

The result can be something that surprises many people: chronically low cortisol levels, not because of a rare disease, but because the stress response itself has become exhausted.

It’s Not Cushing’s. It’s Not Addison’s. So What Is It?

When doctors see abnormal cortisol levels, they typically think of two well-known conditions. Cushing’s syndrome involves too much cortisol, often from a tumor or long-term steroid use. Addison’s disease involves too little cortisol because the adrenal glands themselves are damaged, usually by autoimmune attack.

But there’s a third scenario that doesn’t fit neatly into either box, and it’s far more common than most people realize. It’s sometimes referred to as HPA axis dysregulation, stress-related hypocortisolism, or what researchers call a “blunted cortisol response.”

How Your Stress System Is Supposed to Work

Your body manages stress through a communication chain called the hypothalamic-pituitary-adrenal (HPA) axis. Here’s the simplified version:

1. Your brain detects a threat or stressor.
2. The hypothalamus sends a signal, coritsol releasing hormone (CRH) to the pituitary gland.
3. The pituitary releases Adrenocorticotropic hormone (ACTH), which tells your adrenal glands to produce cortisol.
4. Cortisol helps you respond to the stressor, raising blood sugar, sharpening focus, and dampening inflammation.
5. Once the threat passes, cortisol levels drop back to normal through a feedback loop.

This system works beautifully for short-term stress. The problem begins when stress never lets up.

What Happens When Stress Becomes Chronic

When you’re under prolonged psychological, emotional, or physical stress, think years of caregiving, chronic work burnout, unresolved trauma, or ongoing illness, your HPA axis doesn’t just stay “turned on.” Over time, it can actually start to dial itself down.

Research has shown that while acute and short-term stress raises cortisol, prolonged chronic stress can paradoxically lead to lower-than-normal cortisol output. NCCN[1] This isn’t a sudden failure of the adrenal glands (as in Addison’s disease). Instead, it’s a gradual shift in how the entire stress-signaling system operates.

Scientists believe this happens through several mechanisms:

• Receptor sensitivity changes. After being flooded with cortisol for months or years, the brain’s cortisol receptors can become more sensitive, causing the feedback loop to shut down cortisol production more aggressively than it should. JAMA[2]
• Central downregulation. The hypothalamus and pituitary may reduce their signaling output, essentially “turning down the volume” on the stress response. NEJM[3]
• Adrenal adaptation. The adrenal glands themselves may produce less cortisol in response to the same level of ACTH stimulation. NCCN[1]

The result is a person who is clearly under significant stress but whose cortisol levels are flat or low, the opposite of what you might expect.

Who Does This Affect?

This pattern of low cortisol tied to chronic stress has been documented across a wide range of populations:

• People with burnout and chronic fatigue. Studies have found that individuals with burnout syndrome and chronic fatigue often show flattened diurnal cortisol curves and reduced cortisol awakening responses. JAMA + 1[2-3]
• Trauma survivors. People with post-traumatic stress disorder (PTSD) frequently show lower baseline cortisol levels than healthy controls, which may seem counterintuitive given how “stressed” they feel. NEJM + 1[3-4]
• Chronic pain patients. Conditions like fibromyalgia have been associated with reduced HPA axis activity and lower cortisol output. JAMA[2]
• Caregivers and those under sustained life stress. Long-term caregivers, people experiencing prolonged grief, and those facing ongoing socioeconomic hardship can all develop blunted cortisol responses over time. NCCN[1]

What Does Low Cortisol Feel Like?

Because cortisol plays a role in energy, immune function, mood, and inflammation, people with stress-related low cortisol often experience a cluster of symptoms that can be hard to pin down:

• Persistent fatigue that doesn’t improve with rest
• Increased susceptibility to infections and slow recovery from illness
• Difficulty handling even minor stressors (“feeling overwhelmed by everything”)
• Brain fog and difficulty concentrating
• Muscle and joint aches
• Low mood or emotional flatness
• Worsening of inflammatory conditions

These symptoms overlap with many other conditions, which is one reason this pattern often goes unrecognized.

The Science Behind the Shift

A landmark review of 107 studies examining cortisol and chronic stress found a clear pattern: while cortisol rises in the early phases of stress exposure, it progressively declines as stress becomes more chronic, more uncontrollable, or more traumatic in nature. NCCN[1] The researchers described this as a time-dependent shift; the longer and more severe the stress, the more likely cortisol levels are to fall below normal.

More recent research has reinforced this understanding. Studies on HPA axis function show that chronic psychological stress can fundamentally alter the set point of the cortisol feedback system, leading to a state where the body produces insufficient cortisol relative to its needs. NCCN + 2[1-2][5] This is distinct from adrenal insufficiency; the adrenal glands are capable of producing cortisol, but the signaling system that drives them has been recalibrated.

Why This Matters

Low cortisol from chronic stress isn’t just about feeling tired. Cortisol plays a critical role in regulating inflammation. When cortisol is too low, the body’s inflammatory responses can become poorly controlled, potentially contributing to: JAMA + 1[2][5]

• Autoimmune flare-ups
• Increased pain sensitivity
• Mood disorders
• Metabolic changes

Understanding that chronic stress can suppress, not just elevate, cortisol is important because it changes how we think about treatment. Simply “reducing stress” may not be enough if the HPA axis has already shifted to a new baseline.

What Can Be Done?

Addressing stress-related cortisol suppression typically involves a multi-pronged approach:

• Stress reduction and nervous system regulation. Mindfulness, meditation, yoga, and other mind-body practices have been shown to help restore healthier cortisol patterns over time.
• Sleep optimization. Cortisol follows a circadian rhythm, and poor sleep is both a cause and consequence of HPA axis disruption. Prioritizing consistent, quality sleep is foundational.
• Graduated physical activity. While intense exercise can further stress a depleted system, moderate and consistent movement supports HPA axis recovery.
• Nutritional support. Adequate nutrition, particularly balanced blood sugar, sufficient protein, and key micronutrients like magnesium, vitamin C, and B vitamins, supports adrenal function.
• Professional support. For those with trauma histories or burnout, working with a mental health professional can address the root drivers of chronic HPA activation.

The Bottom Line

Your body’s stress response is powerful, but it isn’t inexhaustible. When stress is relentless, the very system designed to protect you can start to wind down, leaving you with low cortisol, persistent fatigue, and a body that feels like it’s running on empty.

This isn’t Cushing’s. It isn’t Addison’s. It’s your stress response telling you it’s been pushed too far for too long. And the good news is that with the right support, the HPA axis can recover, but it takes time, patience, and a commitment to addressing the root causes of chronic stress.

If any of this resonates with you, there is a reason. Understanding what’s happening in your body is the first step toward feeling like yourself again.