Understanding the Link Between Cortisol and Blood Sugar in Diabetes

Explore how cortisol, the primary stress hormone, can significantly impact blood sugar levels and diabetes management.

By Medha deb

Created on Sep 25, 2025

Explore how cortisol, the primary stress hormone, can significantly impact blood sugar levels and diabetes management.

Cortisol and Blood Sugar: The Science Behind Stress and Diabetes

Cortisol, often called the body’s primary stress hormone, plays a key role in your metabolism, immune response, and—crucially—your blood sugar levels. For people living with diabetes or at risk for this condition, understanding how cortisol affects blood glucose is vital to support better health and disease management. This article explains how cortisol works, its connection to stress, and practical strategies for minimizing its impact on blood sugar control.

What Is Cortisol?

Cortisol is a hormone produced in your adrenal glands, which sit just above your kidneys. It’s essential for maintaining various bodily functions, including:

Regulating blood sugar
Supporting metabolism
Reducing inflammation
Helping control blood pressure
Managing the body’s stress response (“fight or flight”)

Normally, cortisol follows a daily rhythm. Levels peak in the early morning to help you wake up and gradually decline throughout the day, reaching their lowest point at night.

How Does Cortisol Affect Blood Sugar?

During periods of stress, your body undergoes a cascade of changes. One key adaptation is the release of cortisol, which prompts the liver to release more glucose (sugar) into the bloodstream. This surge in glucose is meant to provide your body with enough energy to respond to immediate threats—a useful adaptation in short bursts, but potentially harmful when it becomes chronic.

Cortisol increases glucose production: The liver releases stored glycogen as glucose, rapidly raising blood sugar.
Cortisol decreases insulin sensitivity: Cells become less responsive to insulin, making it harder for glucose to move from the bloodstream into cells.
This response ensures quick energy is available, but when it persists (as with chronic stress), it can lead to consistently elevated blood sugar levels.

In people with type 2 diabetes, who may already have insulin resistance, cortisol’s effects are even more pronounced, worsening glycemic control and complicating diabetes management.

The Connection Between Stress, Cortisol, and Diabetes

Stress triggers the adrenal glands to release cortisol, setting off a domino effect with direct implications for blood sugar. Research indicates:

People with diabetes are more likely to experience a flatter daily cortisol curve, where levels do not fall significantly at night as they should.
Chronic stress and depression are associated with these flatter cortisol profiles, making blood sugar harder to control.
Persistent high cortisol increases glucose production and decreases insulin secretion, both of which raise blood sugar.
Cortisol can also trigger cravings for high-sugar and high-carb foods, further contributing to dysregulated blood glucose.

What Do ‘Flatter’ Cortisol Levels Mean?

Normally, cortisol fluctuates: high in the morning, low at night. In people experiencing ongoing stress or depression, cortisol levels may remain more constant throughout the day and night. This “flattened” pattern is linked to consistently higher blood sugar and increased risk for diabetes-related complications.

Physiological Mechanisms: Why Does Cortisol Disrupt Blood Sugar?

The body’s response to stress is rooted in survival. When the brain perceives a threat, it signals the adrenal glands to release cortisol and adrenaline. Together, these hormones:

Mobilize stored glucose, providing quick energy.
Reduce insulin production temporarily so sugar stays in the bloodstream (where muscles and vital organs can reach it quickly).
Encourage fat breakdown for added energy.

Frequent, repeated stress leads to:

Continual glucose release from the liver
Chronic insulin resistance
Greater accumulation of visceral fat (fat around abdominal organs)
Increased risk for metabolic syndrome and type 2 diabetes

Evidence from Research: Cortisol and Diabetes Outcomes

Several key studies highlight the connections between cortisol, chronic stress, and diabetes:

Ohio State University Study: Researchers found that people with type 2 diabetes and “flatter” cortisol profiles had higher glucose levels. Flatter curves are usually driven by chronic stress or depression.
MESA Stress Exam II: Data from over 800 participants revealed that overall flatter cortisol throughout the day, as well as higher bedtime cortisol, were associated with higher hemoglobin A1c (average blood sugar over three months) in people with diabetes.
Bidirectional links: Diabetes itself can disrupt the body’s cortisol rhythm, creating a cycle: high blood sugar alters cortisol patterns, which then worsen blood sugar control.

**Table: Effects of Cortisol on Blood Sugar and Insulin**
Effect	Explanation
Increased Blood Sugar	Liver releases stored glucose into the bloodstream during stress
Insulin Resistance	Cells become less responsive to insulin, causing higher glucose levels
Decreased Insulin Production	Pancreas may produce less insulin while stress hormones are high
Increased Food Cravings	Cortisol can make you want high-sugar, high-carb foods
Increased Risk for Complications	Higher, poorly controlled blood sugar can worsen heart, kidney, and eye health

Symptoms of High Cortisol and Chronic Stress

Chronic stress and high cortisol can cause nonspecific symptoms. For people with diabetes, these can overlap with symptoms of poor blood sugar control. Watch for:

Feeling overwhelmed, anxious, or irritable
Unexplained weight gain, especially around the abdomen
Difficulty sleeping
Persistent high blood sugar levels despite usual management
Unusual food cravings, particularly for sweets and carbohydrates
Muscle weakness and high blood pressure

It is important to note that many of these symptoms can be linked to other medical conditions. Always discuss persistent or severe changes with your healthcare provider.

Risks of Chronically Elevated Cortisol and Poor Glycemic Control

Without stress management and glucose control, high cortisol and blood sugar levels increase the risk of severe diabetes complications, including:

Heart disease (cardiovascular disease, heart attacks, stroke)
Kidney disease (nephropathy)
Vision problems (retinopathy, macular edema)
Neuropathy (nerve damage)
Impaired wound healing

Early intervention and lifestyle changes can reduce the risks of these long-term complications.

Stress Management Strategies to Lower Cortisol and Improve Blood Sugar

Effectively managing stress plays a crucial role in diabetes control. Evidence-based strategies to support balanced cortisol and better glucose levels include:

Regular physical activity: Exercise helps burn off excess glucose and lowers stress hormone levels.
Consistent sleep schedule: Aim for 7-9 hours each night to support hormone balance.
Mindfulness and relaxation techniques: Practices like meditation, yoga, breathing exercises, and progressive muscle relaxation noticeably lower stress.
Balanced diet: Eat foods rich in fiber and nutrients; reduce ultra-processed foods high in sugar and refined carbs.
Limit caffeine and alcohol: These can disrupt sleep and increase cortisol in some individuals.
Social support: Healthy relationships and support networks reduce perceived stress and promote resilience.
Cognitive behavioral therapy (CBT): Psychotherapy tailored to stress or depression can improve both mood and physical health.
Regular medical checkups: Work with your healthcare provider to optimize medication, monitor A1c, and adjust diabetes treatment plans as needed.

Not every strategy will work for everyone. It may take time and experimentation to find what reduces your stress most effectively.

When to Talk to Your Doctor

If you notice ongoing signs of stress, anxiety, depression, or persistently high blood sugar, consult your healthcare provider. Professional support is especially important if you experience:

Difficulty managing diabetes despite lifestyle changes and medication
Symptoms of depression (loss of interest, sadness, hopelessness)
Severe fatigue or sleep disturbances
Sudden, unexplained changes in weight or blood pressure

Diagnosis and treatment may involve blood tests (including cortisol measurement), medication adjustment, therapy, and referrals to specialists such as endocrinologists or mental health professionals.

Frequently Asked Questions (FAQs)

Q: Can stress cause high blood sugar even without diabetes?

A: Yes. Chronic or intense stress can raise cortisol levels, which in turn increases blood glucose even in individuals without diabetes. Typically, healthy bodies return glucose to normal once the stress passes, but persistent elevation may increase diabetes risk over time.

Q: What foods can help manage both stress and blood sugar?

A: Foods rich in complex carbohydrates (whole grains, beans, vegetables), fiber, healthy fats (nuts, seeds, avocados), and lean protein can promote more stable blood sugar. Certain foods such as leafy greens, fatty fish, and berries have anti-inflammatory properties that may benefit both mood and metabolism.

Q: Are there medications that affect cortisol and blood sugar?

A: Steroid medications (like prednisone or cortisone) raise cortisol, and can significantly increase blood sugar levels. If you are prescribed steroids, your blood sugar may need close monitoring and your diabetes treatment may require temporary adjustment.

Q: How can I tell if my cortisol levels are too high?

A: Signs of high cortisol overlap with symptoms of chronic stress: central weight gain, high blood pressure, fatigue, sleeplessness, muscle weakness, and difficulty focusing. Laboratory tests can confirm abnormal cortisol levels if clinically indicated.

Q: What is a ‘flattened cortisol curve’?

A: This refers to a loss of the normal daily pattern in which cortisol peaks in the morning and falls at night. Instead, levels remain steadier and higher throughout the day and night. This is commonly seen in people with chronic stress, depression, or poorly controlled diabetes, and is linked to worse blood sugar outcomes.

Summary

Cortisol is an essential hormone for health, but chronic elevations—caused by ongoing stress or medical conditions—can raise blood sugar and complicate diabetes management. Recognizing the link between stress, cortisol, and glucose control empowers you to adopt strategies for better health. Regular physical activity, balanced diet, mental health care, and medical monitoring are crucial for maintaining healthy cortisol rhythms and blood sugar levels.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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