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Adrenal Tumors, Cushing Syndrome, Cortisol, and Your Sleep

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Adrenal Tumors, Cushing Syndrome, Cortisol, and Your Sleep

Adrenal tumors are more common than you think, and their impact on cortisol levels can wreak havoc on your sleep. If you've been struggling with poor sleep, fatigue, or unexplained health issues, understanding the connection between adrenal health, cortisol, and rest could be a game-changer. In this article, we'll dive into a recent study on sleep disturbances in patients with Cushing syndrome and mild adrenal hypercortisolism (Subclinical Cushing syndrome, or mild autonomous cortisol secretion; MACS). Don't worry if these terms sound complex—I'll break them down step by step. By the end, you'll have a clearer picture of how these conditions affect sleep and what you can do about them.

1) Understanding Cushing syndrome and mild adrenal hypercortisolism

When hypercortisolism becomes severe and causes obvious symptoms, it's called Cushing syndrome (CS). This can stem from various causes: a pituitary tumor overstimulating the adrenals (Cushing's disease), an adrenal tumor itself, or even rare ectopic tumors elsewhere in the body. Classic signs include weight gain (especially around the abdomen and face, creating a "moon face"), purple stretch marks, high blood pressure, diabetes, muscle weakness, and bone loss. These symptoms are hard to miss and can significantly impact daily life.

But not all hypercortisolism is so overt; in fact, those patients are a minority. Enter mild adrenal hypercortisolism, also known as mild autonomous cortisol secretion (MACS) or subclinical Cushing syndrome. This occurs when an adrenal tumor produces slightly too much cortisol, often without dramatic, rapid physical changes. It's diagnosed through tests like the 1-mg dexamethasone suppression test, where cortisol levels stay above 1.8 μg/dL after taking a suppression pill, indicating the adrenal tumor(s) aren't responding normally to signals to shut down production, i.e., they produce too much cortisol.

Patients with mild adrenal hypercortisolism might not have the full-blown symptoms of Cushing syndrome, but subtle effects build up over time, including risks for heart disease, diabetes, and, as we'll focus on here, sleep disturbances. The key difference? Cushing syndrome is like a cortisol flood; mild adrenal hypercortisolism is a slow leak that still soaks everything.

2) The link between hypercortisolism and sleep problems

Cortisol and sleep have a two-way relationship. Your hypothalamic-pituitary-adrenal (HPA) axis—the system involving your brain and adrenals—regulates both stress responses and sleep cycles. Normally, cortisol dips at night, allowing deep, restorative sleep. But in hypercortisolism, that dip is blunted, leading to fragmented sleep, longer time to fall asleep, and daytime fatigue.

Past studies showed that high cortisol disrupts sleep efficiency (how well you stay asleep), increases awakenings, and alters REM sleep (the dream stage). For overt Cushing syndrome patients, sleep complaints are common; up to 65% report issues. But what about milder cases? Earlier research was limited: small groups, focused on severe Cushing syndrome, and often without validated tools. That's where this new study fills the gap.

3) Key findings from the Mayo Clinic study

A 2025 cross-sectional study from Mayo Clinic researchers, published in The Journal of Clinical Endocrinology & Metabolism, examined sleep in 348 patients with active hypercortisolism (154 with Cushing syndrome, 194 with mild adrenal hypercortisolism; MACS) and 89 healthy referents. They used the Pittsburgh Sleep Quality Index (PSQI), a validated questionnaire scoring sleep quality from 0-21 (higher scores mean worse sleep; ≥5 indicates poor sleep).

The results? Both groups had significantly impaired sleep compared to healthy people. Average PSQI scores were 12 for CS and 11 for mild adrenal hypercortisolism, versus just 5 for referents. Specific issues included:

  • Shorter sleep duration: 24% of CS and 15% of mild patients slept <5 hours nightly (vs. 0% in referents).
  • Longer sleep latency: Over half took longer to fall asleep.
  • Lower sleep efficiency: Many had <65% efficiency (time asleep vs. time in bed).
  • Daytime dysfunction: 70% in CS and 56% in mild reported severe grogginess.
  • Poor overall quality: 75% in CS and 58% in mild-rated sleep as fairly or very bad.
  • Medication use: Over half relied on sleep aids weekly.

After adjusting for age, sex, and body mass index (BMI), sleep problems were similar between CS and mild adrenal hypercortisolism—with no significant differences in PSQI components. But compared to normal people, MACS (subclinical Cushing) patients were far worse off (e.g., nearly 5 times more likely to have severe daytime dysfunction).

Quality of life was also hit hard, measured by the Short Form-36 (SF-36) and CushingQoL questionnaires. Both groups scored below norms, with physical and mental health domains affected. Worse sleep correlated strongly with poorer quality of life.

This study stands out for its large sample, use of validated tools, and inclusion of mild cases, showing that even subtle cortisol excess disrupts sleep as much as severe Cushing syndrome.

4) Factors that make sleep worse in these conditions

The study identified key predictors of poor sleep:

  • Age and sex: Younger patients and women had worse PSQI scores in both groups. Women with mild adrenal hypercortisolism were especially affected, perhaps due to hormonal sensitivities.
  • Clinical severity: In mild cases, higher scores for symptoms like hypertension, diabetes, or obesity are linked to worse sleep. Biochemical severity (lab measures of cortisol) didn't correlate.
  • Obstructive sleep apnea (OSA): Common in these patients (44-45%), but treatment didn't directly tie to PSQI, though addressing it could help overall.
  • Quality of life: Lower SF-36 and CushingQoL scores strongly predicted poor sleep, creating a cycle where bad rest worsens daily function.

In multivariable analysis, for Cushing syndrome, only younger age mattered. For mild adrenal hypercortisolism, younger age, female sex, and higher clinical severity were key. In normal controls? Only higher BMI affected sleep.

These findings highlight that mild adrenal hypercortisolism isn't "mild" when it comes to sleep; younger women with more symptoms are at the highest risk.

5) Improving sleep and quality of life—practical advice

If you suspect an adrenal tumor or hypercortisolism (e.g., unexplained weight gain, fatigue, high blood pressure), see an endocrinologist for testing. Early diagnosis is crucial; adrenal surgery, like the Mini-Back Scope Adrenalectomy (MBSA), can remove problematic tumors with minimal invasion, often curing excess cortisol production.

For sleep specifically:

  • Address the root cause: If mild adrenal hypercortisolism is confirmed, discuss options like surgery with Mini-Back Scope Adrenalectomy (MBSA).
  • Lifestyle tweaks: Stick to a consistent sleep schedule, avoid caffeine late, and create a cool, dark bedroom. Exercise regularly, but not close to bedtime.
  • Manage comorbidities: Treat OSA with CPAP, control blood pressure and blood sugar; these improve sleep indirectly.
  • Medications and therapy: Short-term sleep aids might help, but cognitive behavioral therapy for insomnia (CBT-I) is the gold standard for long-term fixes.
  • Monitor cortisol rhythms: Some use stress-reduction techniques to support natural cortisol dips.
  • Follow-up care: Post-surgery, work with your doctor on hormone replacement if needed (e.g., hydrocortisone) to avoid glucocorticoid withdrawal syndrome.

Remember, poor sleep from hypercortisolism isn't just annoying, it's linked to higher risks for heart issues and mood disorders. But with proper treatment and surgical cure, many patients see dramatic improvements. If this resonates, don't hesitate to seek expert care. We've helped countless patients regain restful nights and better health.

Reference

Dr. Tobias Carling, of the Carling Adrenal Center, is one of the world's leading experts in adrenal gland surgery. Dr. Carling performs more adrenal operations than any other surgeon in America. Dr. Carling left Yale University in 2020 to open the Carling Adrenal Center in Tampa, Florida.

To discuss the details of your case with Dr. Carling and become his patient, fill out the new patient form and he will be in touch with you shortly.

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Author

Dr. Tobias Carling MD, PhD, FACS

Dr. Carling is the most experienced adrenal surgeon in the United States, and by far the world's most knowledgeable surgeon-scientist when it comes to adrenal gland function and disease, adrenal tumors and cancer, and all forms of adrenal gland surgery. Dr. Carling has more experience with advanced minimally invasive adrenal and endocrine operations than any surgeon in the United States. A fellow of the American College of Surgeons, Dr. Carling is a significant member of both the American Association of Endocrine Surgeons (AAES) and the International Association of Endocrine Surgeons (IAES).