Stress and Blood Sugar: Cortisol, Anxiety and Diabetes

Stress and blood sugar are linked, but the lab evidence is small and patchy. In lab studies stress raised glucose in some people with type 2 diabetes, mostly after a meal.^[3][2] This guide covers cortisol, anxiety, depression and what small trials show about coping tools. Where the data are thin we say so. For emotional eating see our stress eating guide.

This guide is general education. If you use insulin or other glucose medicines, follow the plan your diabetes team gave you.

How are stress and blood sugar linked?

Stress hormones make insulin work less well. Diabetes UK says cortisol and adrenaline make it harder for insulin to work properly, known as insulin resistance. It adds that stress which does not go away can keep blood sugar high.^[1] The NHS notes the body releases these hormones when you feel anxious or scared.^[7]

How does cortisol affect blood sugar?

Cortisol and blood sugar are linked in human physiology studies. In a 1982 study six healthy volunteers had cortisol infused for 24 hours. Levels rose about 4-fold to those seen in moderately severe stress. Fasting glucose rose from 97 to 126 mg/dL (5.4 to 7.0 mmol/L).^[8]

Six people took part and cortisol stayed high for a full day. A short bad afternoon will not do the same. Diabetes UK also says stress does not cause diabetes but can affect your blood sugar and how you look after your condition.^[1]

Does stress raise blood sugar?

Sometimes, and only in some people. In a lab study of 22 adults with type 2 diabetes glucose rose by a mean 18.4 mg/dL (1.0 mmol/L) after a threat of electric shock. Nine healthy adults stayed stable. The other stressor produced no clear rise.^[3]

Meal timing seemed to matter. In 30 adults with type 2, a standard social stress test came 75 minutes after a meal. Glucose was 1.5 mmol/L (27 mg/dL) higher than on a control day (95% CI 0.5 to 2.4). Only 10 were tested fasting. Their change was not significant.^[2] In 40 adults with type 1, fasting glucose stayed unchanged. After a meal, stress delayed the fall by 45 minutes.^[9]

All of these studies were small and short, and they ran in a lab. The Goetsch authors say results in daily life remain to be shown.^[3] If you want your own data, our self-monitoring guide explains how to log readings with notes on stress.

What the stress and cortisol studies found

Study.	What the evidence says.	Practical point.
Rizza 1982, 6 healthy volunteers.[8]	A 24-hour cortisol infusion raised fasting glucose from 97 to 126 mg/dL (5.4 to 7.0 mmol/L).[8]	Sustained high cortisol impairs insulin action, unlike a brief stressful afternoon.[1][8]
Goetsch 1993, 22 adults with type 2 and 9 healthy adults.[3]	Glucose rose by a mean 18.4 mg/dL (1.0 mmol/L) in type 2 under one lab stressor, while healthy adults stayed stable.[3]	Lab responses vary by person and stressor.[3]
Faulenbach 2012, 30 adults with type 2 diabetes.[2]	Post-meal stress raised glucose by 1.5 mmol/L (27 mg/dL) against a control day. Fasting stress showed no significant change.[2]	Mealtime stress is more likely to show on your meter than fasting stress.[2]
Wiesli 2005, 40 adults with type 1 diabetes.[9]	Post-meal stress delayed the glucose fall by 45 minutes, while fasting glucose stayed unchanged.[9]	Log stressful meals alongside your readings to spot your own pattern.[9]

Does stress affect blood sugar in people without diabetes?

The evidence is thin. In the nine healthy adults of the lab study, glucose remained stable under stress.^[3] The cortisol infusion did raise fasting glucose in six healthy volunteers, but at a sustained high dose for 24 hours.^[8] We found no larger study of everyday stress in adults without diabetes.

So a stressful week does not turn normal readings into diabetes. Diabetes UK states that stress does not cause diabetes.^[1] If you are worried about your numbers, ask your GP or primary care team about an HbA1c test. Our HbA1c guide explains the result.

Can anxiety cause blood sugar spikes?

Evidence that anxiety raises readings is mixed. A 2002 meta-analysis of 11 studies found no overall link between anxiety and glycemic control. It did find a link with high glucose in studies that used diagnostic interviews.^[10] Anxiety and blood sugar do share symptoms, though. The ADA cites a meta-analysis with a pooled prevalence of anxiety disorders of 28% in people with diabetes. It warns that anxiety symptoms may overlap with diabetes distress or high glucose symptoms.^[11]

The overlap runs to lows as well, particularly if you use insulin or a sulfonylurea such as gliclazide or glimepiride.^[7][12] The NHS lists feeling anxious or irritable, sweating, shaking and heart palpitations as signs of low blood sugar. It says to check your blood sugar if you can.^[7] Low blood sugar usually means below 4 mmol/L (72 mg/dL) in the UK or below 70 mg/dL (3.9 mmol/L) in the US, which means you follow your low blood sugar plan.^[7][12] See our guide to low blood sugar.

The ADA advises screening for anxiety symptoms and for diabetes distress at least once a year.^[11] Diabetes distress is the strain of living with diabetes. The ADA says it is distinct from depression and anxiety.^[11]

Is stress linked with type 2 diabetes?

Research on stress and diabetes risk is mixed, and the firmest evidence is for depression. Two meta-analyses link depression with later type 2 diabetes. One found a relative risk of 1.60 (95% CI 1.37 to 1.88) in 13 studies. The other found an adjusted 1.38 (95% CI 1.23 to 1.55) in 23 studies.^[4][5]

These are associations. Depression is not the same as everyday stress, and the studies were observational. The larger one says the link could not be fully explained by antidepressants or weight.^[5] The first also found a modest risk of depression after diabetes, with a relative risk of 1.15.^[4] We found no meta-analysis of everyday stress and later type 2 diabetes.

What helps with stress and blood sugar in diabetes?

Several tools help how people feel, and their effect on HbA1c is small. A meta-analysis of eight trials with 841 people found mindfulness programmes gave an HbA1c 0.25 percentage points (2.7 mmol/mol) smaller. Stress scores improved by a moderate effect. The authors call the HbA1c change slight.^[6]

Wider reviews agree. In 70 trials with 14,796 adults with type 2, the authors concluded psychological interventions have minimal clinical benefit for glycaemic control.^[13] In 16 studies, short-term diabetes distress improved while the change in HbA1c was not significant.^[14] The ADA says several strategies reduce diabetes distress and, to a lesser degree, improve glycemic outcomes.^[11]

Exercise has firmer HbA1c data in type 2. A review of 47 trials with 8,538 people found that in the 23 structured exercise studies HbA1c was 0.67 percentage points (7.3 mmol/mol) smaller than in controls. More than 150 minutes a week gave 0.89 (9.7 mmol/mol), and 150 minutes or less gave 0.36 (3.9 mmol/mol). Advice alone showed no change.^[15] Results varied a lot between trials, and none tested stress. See our exercise guide.

1. Check your blood glucose when you feel shaky, sweaty or anxious to rule out a reading below 4 mmol/L (72 mg/dL) in the UK or below 70 mg/dL (3.9 mmol/L) in the US, especially if you use insulin or a sulfonylurea such as gliclazide or glimepiride.^[7][12]
2. Note stressful days alongside your mealtime readings so you and your care team can see your own pattern.^[3][2]
3. Build up regular structured exercise each week, which showed a larger HbA1c change in trials than advice alone.^[15]
4. Ask your GP or diabetes team about screening for diabetes distress or anxiety at least once a year.^[11]

When should you get help?

Talk to your care team if stress is hard to cope with. In England you can self-refer to NHS talking therapies if you are 18 or over, with no GP visit needed. If you need urgent mental health help, call NHS 111 or use 111 online. Call 999 or go to A&E if your life or someone else's life is at risk.^[7] In the US, call or text 988 to reach the 988 Suicide and Crisis Lifeline. Call 911 if someone is in immediate danger.^[16] If you are somewhere else, use your national crisis line or your local emergency number. For severe low blood sugar, in the UK the NHS says to call 999 if someone may have very low blood sugar and is not responding normally or is unconscious, and a glucagon injection is not available or you do not know how to use it, or they have not recovered within 10 minutes of a glucagon injection, or they have been drinking alcohol.^[7] In the US, the ADA says to call 911 right away if someone is unconscious and glucagon is not available or no one knows how to use it.^[12]

Questions to ask your diabetes team

• Can you screen me for diabetes distress or anxiety at my next review?^[11]
• How can I tell whether shakiness and a fast heartbeat are anxiety or low blood sugar?^[7][11]
• Should I check my glucose after a stressful meal, and what should I do with a one-off high reading?^[2][1]
• Can you refer me to NHS talking therapies or a mental health professional who works with diabetes?^[7][11]

Frequently asked questions

Does stress raise blood sugar?

Sometimes. In lab studies glucose rose in some people with type 2 diabetes, mostly after a meal, by 1.5 mmol/L (27 mg/dL) in one study. It stayed stable in nine healthy adults and did not change significantly in people tested fasting.^[2][3]

How does cortisol affect blood sugar?

It makes insulin work less well. Diabetes UK says cortisol and adrenaline make it harder for insulin to work properly. In six healthy volunteers a 24 hour cortisol infusion raised fasting glucose from 97 to 126 mg/dL (5.4 to 7.0 mmol/L).^[1][8]

Can anxiety feel like low blood sugar?

Yes. The NHS lists feeling anxious or irritable, sweating, shaking and heart palpitations as symptoms of low blood sugar. If you have diabetes check your glucose first. A reading below 4 mmol/L (72 mg/dL) in the UK or below 70 mg/dL (3.9 mmol/L) in the US means you follow your low blood sugar plan.^[7][12]

Does stress cause diabetes?

No. Diabetes UK says stress does not cause diabetes but can affect your blood sugar and how you look after your condition. Depression, which is not the same as everyday stress, went with a higher risk of later type 2 diabetes in two meta-analyses. That shows association only.^[1][4][5]

Where to go next

Checking your meter when symptoms overlap, building steady activity and asking your care team for support with diabetes distress can help you manage stress and blood sugar together.

• Stress eating and blood sugar, for cravings and how to break the cycle.
• Exercise and glucose levels, for simple daily activity ideas.
• Is Diabec legit?, for what is in our supplement and what it does not do.

Note: If you are pregnant, breastfeeding, or considering giving any supplement or herbal product to a child, consult your healthcare provider before making any changes to your diet, supplement routine, or prescribed medications.