The two small glands sitting on top of your kidneys are among the body’s main sugar-raising organs, working against insulin, which lowers blood sugar. Their job is to keep enough fuel in the blood when you haven’t eaten or when you’re under stress. But the same hormones that protect you in an emergency can push blood sugar toward diabetes when they run too high for too long, and let it drop when they run too low.
The Two Adrenal Hormones That Raise Blood Sugar
Each adrenal gland has two parts that make different hormones. The outer layer makes cortisol, a steroid hormone. The inner core makes adrenaline (also called epinephrine) and noradrenaline.1Endocrinology & Diabetes Research. Adrenal Gland’s Role in Metabolism and Energy Regulation: Insights and Implications That gives the gland two separate sugar-raising systems, one slow and one fast.
Cortisol is the slow, steady supply. It tells the liver to make new glucose from protein building blocks and fat.2Endocrinology & Diabetes Research. Adrenal Gland’s Role in Metabolism and Energy Regulation: Insights and Implications It also switches on the liver genes that build this sugar-making machinery, an effect that takes hours rather than seconds.3Fabad Eczacılık Bilimler Dergisi. The Role of Glucocorticoids in Hepatic Gluconeogenesis, Associated Pathologies, and Novel Therapeutic Approaches Cortisol breaks down stored fat into fatty acids that can be burned for energy, and it makes muscle and fat take up less glucose, saving it for the brain.4Endocrinology & Diabetes Research. Adrenal Gland’s Role in Metabolism and Energy Regulation: Insights and Implications The result is a mild insulin resistance, meaning cells respond less to insulin’s signal to absorb sugar.5PubMed Central. Effects of glucocorticoid excess on the sensitivity of glucose transport and metabolism to insulin in rat skeletal muscle
Adrenaline is the emergency supply. It quickly breaks down glycogen, the sugar stored in the liver and muscles, into glucose.6Endocrinology & Diabetes Research. Adrenal Gland’s Role in Metabolism and Energy Regulation: Insights and Implications At the same time it holds back the release of insulin from the pancreas.7PubMed. A Receptor Mechanism for the Inhibition Of Insulin Release by Epinephrine in Man So sugar rises within minutes, and insulin is kept from bringing it back down.
Insulin is the only major hormone that lowers blood sugar. Glucagon from the pancreas, cortisol and adrenaline all push it up, which is why too much adrenal hormone raises sugar and too little can let it fall.
Why Stress Raises Your Blood Sugar
During stress, the brain signals the adrenal glands to release more cortisol.8PubMed Central. Stress-Induced Hyperglycemia: Consequences and Management Cortisol, the adrenaline system and inflammation signals then work together to raise blood sugar during illness or injury.9PubMed Central. Stress hyperglycemia: an essential survival response! The brain, immune cells and blood cells use glucose without needing insulin, so extra sugar in the blood feeds them during stress, injury and infection.10PubMed Central. Stress-Induced Diabetes: A Review A temporary rise during a bad infection or after surgery is partly the body protecting itself.
Illness can raise sugar even on days you eat very little, because the liver releases extra glucose under the influence of stress hormones. The rise usually eases as the illness resolves, so a high reading that lingers after recovery is worth noticing. Checking sugar more often while ill helps catch rises early.
Long-term stress is different. Prolonged stress can leave cortisol chronically high, or sometimes blunted, which contributes to insulin resistance, belly fat and type 2 diabetes.11Endocrines. The Stress Axis in Obesity and Diabetes Mellitus: An Update In a large study of Black adults, higher morning cortisol went with higher fasting sugar and higher HbA1c, a blood test that reflects average sugar over about three months, most strongly in people with type 2 diabetes.12PubMed Central. The Association of Morning Serum Cortisol with Glucose Metabolism and Diabetes: The Jackson Heart Study
Sleep and shift work shift the cortisol clock. Cortisol normally peaks in the morning and falls through the evening. Night-shift workers and people with sleep disorders often show a weak morning rise and high evening cortisol.13PubMed Central. Modified Cortisol Circadian Rhythm: The Hidden Toll of Night-Shift Work That pattern can lead to higher fasting sugar and poorer glucose handling.14PubMed Central. Modified Cortisol Circadian Rhythm: The Hidden Toll of Night-Shift Work The normal morning cortisol surge in healthy people, though, doesn’t appear to be what sets waking blood sugar.15PubMed. The awakening cortisol response and blood glucose levels
Many diabetes teams give written sick day rules for exactly this reason. They cover how often to check sugar, how to keep drinking fluids, and when to call for help. Don’t simply stop diabetes medicine because you aren’t eating; ask your care team in advance which medicines to continue, change, or hold. Insulin users often still need insulin when ill, because stress hormones keep driving sugar up even without meals. Persistent vomiting, severe thirst, or readings that stay very high are reasons to call promptly rather than wait it out.
When stress is ongoing rather than one-off, a few habits help most. Keep sleep times as regular as you can, even on shift rotations. Regular physical activity helps muscles take up sugar despite cortisol. And if readings stay high after an illness has passed, tell your doctor.
Steroid Medicines and High Blood Sugar
Medicines such as prednisone, dexamethasone and methylprednisolone work like cortisol. They can cause new high blood sugar in people without diabetes and severely uncontrolled sugar in people who have it.16PubMed Central. Glucocorticoid-Induced Diabetes Mellitus: An Important but Overlooked Problem Steroid-caused diabetes is common across nearly every medical specialty, yet often goes unnoticed.17PubMed Central. Glucocorticoid-Induced Diabetes Mellitus: An Important but Overlooked Problem
The type of steroid matters. In hospital patients, dexamethasone and methylprednisolone raised fingerstick sugar more than prednisolone and hydrocortisone.18PubMed. The effect of different types of oral or intravenous corticosteroids on capillary blood glucose levels in hospitalized inpatients with and without diabetes People on the stronger types may need closer sugar checks.19PubMed. The effect of different types of oral or intravenous corticosteroids on capillary blood glucose levels in hospitalized inpatients with and without diabetes With one morning dose, the rise often shows up in the afternoon and evening rather than before breakfast. A fasting-only check can therefore look normal while the problem goes unseen. If you check once a day, ask whether a reading a few hours after your dose, or before dinner, would be more informative.
The symptoms are easy to blame on the illness being treated: rising thirst, frequent urination, blurry vision and tiredness. Higher doses and longer courses raise the chance of high sugar, and the effect generally follows the dose. People with diabetes, prediabetes, older age, or a family history of diabetes are more likely to have troublesome highs.
If you’re prescribed steroids, ask whether your sugar should be checked during the course. If you have diabetes, ask in advance how to adjust your medicine. Never stop a long steroid course suddenly; taper as directed, because your body’s own cortisol may be suppressed.
For many people, sugar returns toward normal as the dose is lowered or stopped. People with prediabetes or other risk factors may be left with lasting diabetes. A follow-up sugar or A1c test after the course confirms where you stand.
Adrenal Diseases That Cause High Blood Sugar
Cushing’s syndrome is a condition of long-term excess cortisol, from a tumor or long steroid use. It attacks sugar control from several sides. The liver overproduces glucose, and both liver and muscle respond less to insulin.20S. Karger AG. Pathophysiology of diabetes mellitus in Cushing’s syndrome Muscles normally use 70 to 80% of the body’s glucose, and Cushing’s breaks down muscle, which further cuts sugar uptake.21PubMed Central. Diabetes Mellitus Secondary to Cushing’s Disease Fat collects around the belly and organs, worsening the insulin resistance.22S. Karger AG. Pathophysiology of diabetes mellitus in Cushing’s syndrome Excess cortisol also impairs insulin release from the pancreas, which is likely what tips some people from borderline sugar into diabetes.23S. Karger AG. Pathophysiology of diabetes mellitus in Cushing’s syndrome
Signs that point toward Cushing’s rather than ordinary type 2 diabetes include a rounded face and fat buildup at the upper back and belly with thin arms and legs, wide purple stretch marks, easy bruising, and muscle weakness, especially climbing stairs. New high blood pressure alongside new diabetes is another. It’s easy to miss, because type 2 diabetes, high blood pressure and weight gain are extremely common on their own. The clue is often a cluster of features that don’t fit the usual story or that appeared quickly. Most people with type 2 diabetes don’t have Cushing’s, and testing is usually reserved for those with several suggestive features.
A pheochromocytoma is a usually benign adrenal tumor that releases excess adrenaline and noradrenaline. It reduces insulin release and makes body tissues resist insulin.24PubMed Central. Glucose Intolerance on Phaeochromocytoma and Paraganglioma—The Current Understanding and Clinical Perspectives About half of people with these tumors have abnormal blood sugar,25PubMed Central. Glucose Intolerance on Phaeochromocytoma and Paraganglioma—The Current Understanding and Clinical Perspectives and diabetes itself appears in roughly a quarter to half of cases.26PubMed Central. Secondary diabetes mellitus in pheochromocytomas and paragangliomas Diabetes in a young, lean person with high blood pressure can be a clue,27PubMed Central. Glycemic Disturbances in Pheochromocytoma and Paraganglioma as can blood sugar that resists standard diabetes treatment.28PubMed Central. Glycemic Disturbances in Pheochromocytoma and Paraganglioma
The warning pattern is spells of pounding heartbeat, headache and sweating, along with blood pressure that surges or is hard to control. Those spells together with new high sugar warrant asking about urine or blood tests for adrenaline breakdown products. After the tumor is removed, sugar can drop too low, so it’s watched closely after surgery.29PubMed Central. Glucose Intolerance on Phaeochromocytoma and Paraganglioma—The Current Understanding and Clinical Perspectives
Treating the cause often helps. Removing the excess hormone often improves or resolves the diabetes, though some people still need diabetes medicine afterward. Sugar medicines may need lowering quickly after treatment to avoid lows.
When the Adrenals Make Too Little and Sugar Drops
Adrenal insufficiency means the glands, or the pituitary signal driving them, don’t produce enough cortisol. The body then makes less of its own glucose.30PubMed Central. Hypoglycaemia in adrenal insufficiency Tissues also become more sensitive to insulin and pull more sugar from the blood.31PubMed Central. Hypoglycaemia in adrenal insufficiency The risk of a low-sugar episode rises, especially during fasting or illness.32PubMed Central. Hypoglycaemia in adrenal insufficiency
It’s a hidden cause worth testing for. In one emergency department, about 6% of people with low blood sugar turned out to have adrenal insufficiency.33Journal of the Endocrine Society. Frequency of Adrenal Insufficiency in Patients With Hypoglycemia in an Emergency Department: A Cross-sectional Study Most of those cases came from the pituitary gland rather than the adrenals themselves.34Journal of the Endocrine Society. Frequency of Adrenal Insufficiency in Patients With Hypoglycemia in an Emergency Department: A Cross-sectional Study Unexplained lows in someone not on diabetes medicine are worth discussing with a doctor, and cortisol testing is often part of the workup.
Lows tend to appear after a long gap without eating, such as overnight or during a day of poor appetite. Illness, vomiting or diarrhea can set one off, and may also bring on a dangerous adrenal crisis in someone who lacks cortisol. Children are especially prone to fasting lows, so unexplained low sugar in a child warrants medical attention.
Other symptoms include lasting fatigue, weight loss and poor appetite, and dizziness on standing from low blood pressure. In the adrenal form, salt cravings and darker skin appear. Low-sugar symptoms such as shakiness, sweating and confusion can join them.
An early-morning blood cortisol level is often the first test. A stimulation test gives a hormone shot and measures how much cortisol rises. Treatment replaces cortisol with daily tablets, which usually stops the lows.
Adrenaline as a Backup When Diabetes Causes Lows
When sugar drops after too much insulin, rising glucagon is what’s essential for recovery, while cortisol rises play little part in the first hours.35PubMed. Hormonal mechanisms in acute glucose counterregulation: The relative roles of glucagon, epinephrine, norepinephrine, growth hormone, and cortisol When the glucagon response is impaired, adrenaline becomes critical.36PubMed. Hormonal mechanisms in acute glucose counterregulation: The relative roles of glucagon, epinephrine, norepinephrine, growth hormone, and cortisol Many people with long-standing type 1 diabetes lose their glucagon response to lows.37PubMed. Important role of adrenergic mechanisms in acute glucose counterregulation following insulin-induced hypoglycemia in type I diabetes. Evidence for an effect mediated by beta-adrenoreceptors. For them, adrenaline is the main defense, and it also causes the warning shakes and sweating.
Those symptoms are an alarm: shakiness, sweating, pounding heart and anxiety come largely from adrenaline surging as sugar falls, and they prompt you to eat or drink something sugary before your brain runs short of fuel. Confusion, slurred speech and drowsiness come from the brain itself lacking sugar, and tend to appear later.
Repeated lows are dangerous because they can blunt the adrenaline response and its warning symptoms. After many lows, the body can lower the sugar level at which adrenaline is released, so the alarm sounds late or not at all. Doctors call this hypoglycemia unawareness, a term you may hear from your care team. Someone in this state may go straight from feeling fine to confused, and may need others to notice. Avoiding lows for a few weeks often helps warning signs return. Beta-blocker heart drugs can also mask adrenaline’s warning signs, which is worth asking your doctor about. If you notice you no longer feel lows coming, mention it; care teams often ask about it directly.
What About DHEA and Aldosterone
Aldosterone is an adrenal hormone that controls salt and potassium. Excess aldosterone lowers potassium, which was first thought to impair insulin release.38PubMed Central. Effects of aldosterone on insulin sensitivity and secretion Correcting the low potassium only partly restored insulin release, though.39PubMed Central. Effects of aldosterone on insulin sensitivity and secretion In mice, aldosterone directly reduced insulin release.40PubMed Central. Aldosterone decreases glucose-stimulated insulin secretion in vivo in mice and in murine islets
Hard-to-control high blood pressure with low potassium suggests excess aldosterone. A blood test comparing aldosterone with renin can check for it, and treating it can help both blood pressure and sugar handling.
DHEA is another adrenal hormone. In older adults, a year of DHEA replacement lowered insulin resistance by about 22%.41PubMed Central. Dehydroepiandrosterone (DHEA) replacement decreases insulin resistance and lowers inflammatory cytokines in aging humans But the sugar benefit appeared only in those who already had abnormal glucose tolerance.42PubMed Central. Dehydroepiandrosterone (DHEA) replacement decreases insulin resistance and lowers inflammatory cytokines in aging humans DHEA isn’t a proven diabetes treatment, and supplements should be discussed with a doctor.
Caution is reasonable. DHEA is sold over the counter, but a supplement’s strength and purity can vary and its long-term effects aren’t well established. The body converts it into sex hormones, so it can have effects beyond blood sugar, and anyone with a hormone-sensitive condition should be especially careful.