What Happens to Your Body When Cortisol and Stress Build Up?

Each day, you are faced with stressful situations—and some of them may leave you feeling physically as well as emotionally frazzled. This is because when faced head-on with an uncomfortable situation, your body reacts, preparing to protect you from whatever you are facing.

For example, we all know what it's like to feel startled, such as when you hear an unexpected loud noise. You may feel your heart rate increase, but as soon as your mind has confirmed that there's nothing to worry about (it was just someone dropping a water bottle), most of us quickly return to normal.

That quick "jolt" is caused by your adrenal glands—critical parts of your HPA axis—sending out a burst of chemical messengers (including adrenaline and cortisol) so you can react, focus, and stay safe.

But in today's world, stress often doesn't switch off so easily. When pressures pile up day after day, the stress response can stay activated. Instead of brief, helpful spikes, cortisol remains elevated for longer stretches of time.

This ongoing stress can feel like being stuck on high alert or burned out. Understanding how cortisol works—and how to test cortisol levels and support a healthy balance—can help your body recover more effectively after stress.

What is cortisol and why does the body release it?

Cortisol is a glucocorticoid hormone produced by the adrenal glands, and it is essential for survival. While it's commonly called the "stress hormone," its role extends far beyond stress alone. Cortisol helps regulate blood pressure, blood sugar, immune activity, and how your body responds to insulin—all functions that are critical for overall health.

Your body produces cortisol continuously, even at rest. Levels rise when you're faced with a physical or emotional challenge, helping to mobilize energy and sharpen your focus. This process is controlled by the hypothalamic-pituitary-adrenal (HPA) axis, the body's built-in stress response system.

When your brain perceives a stressor, the hypothalamus releases hormones that stimulate the adrenal glands to release epinephrine (adrenaline) and cortisol into the bloodstream. As cortisol levels rise, they signal the brain to dial the adrenaline response down, preventing the system from staying in overdrive.

Cortisol itself isn't harmful. In fact, it's protective. It helps you respond in high-pressure situations, whether navigating daily demands or handling a crisis. Problems arise only when cortisol levels remain chronically too high. Chronic stress like this affects nearly every system in your body—including immune function, metabolism, digestion, mood, and sleep—and can contribute to inflammation and long-term health risks.

Both high cortisol (from prolonged stress or Cushing's syndrome) and low cortisol (as in adrenal insufficiency) can be cause for concern. The key is balance: When cortisol is properly regulated, it supports your health while allowing your body to respond to stress effectively.

"Cortisol itself isn't harmful. In fact, it's protective. It helps you respond in high-pressure situations…Problems arise only when cortisol levels remain chronically too high."

How does stress trigger cortisol in the body?

When you feel stressed, your body activates the HPA axis. This triggers a cascade of hormonal signals that includes cortisol release, helping you respond to the challenge at hand.

• Short-term stress: When you're startled by a close call in traffic, are navigating a tense conversation, or are racing to meet a deadline, you're experiencing short-term stress, which triggers the fight-or-flight response. Adrenaline rises first, increasing your heart rate and blood pressure within seconds. Cortisol comes next, peaking about 30 minutes later to help maintain focus and energy until the situation resolves. Afterward, levels drop, and the body settles back into balance.
  
• Chronic stress: When stress persists—due to ongoing work pressures, caregiving demands, poor sleep, or persistent worry—the HPA axis remains activated, and cortisol stays elevated. This can disrupt the body's natural rhythm, contribute to fatigue and mood changes, weaken immune defenses and make it harder for your body to recover from stress.

How does high cortisol affect the body over time?

While short bursts of cortisol help your body respond appropriately when needed, chronically elevated cortisol can have widespread effects:

• Immune function and inflammation: Chronically high cortisol can weaken your immune system, making it harder to fight infections. It can also promote a state of low-grade, non-resolving inflammation, which can lead to problems like diabetes and heart disease.
• Metabolism: Chronically elevated cortisol can raise your blood sugar and make your body less sensitive to insulin and increase visceral fat. These changes can lead to weight gain, high blood pressure, high cholesterol, and a higher risk for diabetes and heart disease.
• Digestive health: Chronically high cortisol can affect your digestive system, altering the bacterial composition of your gut microbiome, the functioning of your gut barrier and digestive movement. Chronic excess cortisol can increase your gut lining's permeability, allow the overgrowth of harmful bacteria in your gut, and contribute to gastrointestinal symptoms like pain, bloating or altered bowel habits. These changes also contribute to inflammation.
• Cardiovascular health: Long-term high cortisol can damage your heart and blood vessels. It raises your risk for high blood pressure, heart attacks, strokes and arrhythmias.
• Brain and mood: Chronically high cortisol comes with an increased risk of anxiety, depression and cognitive changes.

What are the symptoms of high cortisol?

Elevated cortisol can affect your mind, body and sleep. Common signs include:

• Mood changes: Anxiety, irritability or trouble focusing
• Physical symptoms: Fatigue, headaches, abdominal weight gain, muscle weakness, high blood pressure, easy bruising and sometimes purple stretch marks
• Sleep disturbances: Difficulty falling or staying asleep

What is cortisol testing? How can testing for cortisol help me?

Cortisol testing measures your body's primary stress hormone in blood, urine or saliva to assess whether levels are within a healthy range. Cortisol normally follows a daily rhythm—highest in the morning to help you wake up and lowest at night to support sleep. A blood test provides a useful snapshot of how your stress response system is functioning.

Because cortisol influences energy, sleep, metabolism and blood sugar regulation, imbalances may contribute to symptoms like fatigue, poor sleep or difficulty coping with stress. Testing can help clarify whether cortisol may be part of the picture.

A comprehensive blood test can evaluate cortisol alongside other stress-related markers, offering a broad view of how your body is responding to stress and helping guide strategies for restoring balance. In some cases, salivary cortisol testing may be used as a follow-up. Multi-point saliva tests measure cortisol at several times throughout the day and can help assess whether the natural daily rhythm is intact—particularly if blood cortisol results are abnormal.

If you're wondering whether stress hormones may be affecting how you feel, talk with your doctor about which type of cortisol testing is most appropriate for you.

How can you lower excessive cortisol levels?

Cortisol isn't the enemy—it's essential for survival. The goal is to prevent it from staying elevated longer than necessary. The good news is that there are practical, effective ways to support healthy cortisol balance.

• Move regularly: Physical activity helps discharge stress and bring cortisol back to baseline. Walking, strength training, cycling, dancing, or any consistent movement counts.
• Live a balanced lifestyle: Nourishing meals, consistent routines, and supportive social connections all play a role in stress regulation. Maintaining healthy relationships—and setting boundaries around stressful ones—can significantly reduce ongoing emotional strain.
• Prioritize sleep: Quality sleep helps reset the nervous system and is one of the most reliable ways to support healthy cortisol levels.
• Let go of what you can't control: Don't sweat the small stuff. Instead, focus on what you can change. Focusing on what's within your control can reduce stress and prevent cortisol from staying elevated for too long.
• Use mind–body tools: Practices like yoga, tai chi, meditation, cognitive behavioral therapy (CBT), breathing exercises, and even warm baths activate the parasympathetic nervous system, helping to bring cortisol back into balance.

How long does it take to lower cortisol naturally?

For short-term stress, cortisol usually returns to baseline fairly quickly once the stressor passes. With chronic stress, improvement can take weeks to months of consistent lifestyle and behavioral changes.

Does anxiety increase cortisol levels?

Yes. Ongoing anxiety is a form of chronic stress and can keep cortisol elevated by repeatedly activating the body's stress response.

What's the difference between adrenal fatigue and cortisol imbalance?

"Adrenal fatigue" is not a recognized medical diagnosis. It refers to the idea that chronic stress exhausts the adrenal glands, leading to low cortisol. Actual cortisol imbalances are endocrine conditions—such as high cortisol in Cushing's syndrome or low cortisol in adrenal insufficiency—and require medical evaluation and treatment.

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