Does Stress Raise Blood Sugar? Causes and Tips

Stress raises blood sugar by triggering the release of hormones that flood the bloodstream with glucose, a response that can be particularly significant for people with diabetes or prediabetes. When the body perceives a threat, adrenaline and cortisol work together to mobilise energy rapidly. In healthy individuals, insulin usually restores balance quickly. However, for those with impaired insulin function, stress-related glucose spikes can persist and accumulate over time. This article explains the mechanisms involved, who is most at risk, practical strategies for managing stress-related blood sugar changes, and when to seek medical advice.

Does stress raise blood sugar levels?

Yes, stress raises blood sugar in both people with and without diabetes by triggering hormonal release of glucose into the bloodstream. Chronic stress is more clinically significant than acute stress, as it can cause persistently elevated glucose levels.

Yes, stress can raise blood sugar levels, both in people with diabetes and in those without a diagnosed condition. When the body perceives a threat, whether physical or psychological, it triggers a hormonal response that causes glucose to be released into the bloodstream. This is a normal survival mechanism, but when stress is frequent or prolonged, the resulting blood sugar fluctuations can become clinically significant.

For most healthy individuals, the body compensates by releasing insulin to bring glucose back to a normal range. However, for people with type 1 or type 2 diabetes, or those with insulin resistance, this compensatory mechanism is impaired, meaning blood sugar can remain elevated for longer than it should.

It is worth noting that not all stress has the same effect. Acute stress, such as a sudden fright, tends to cause a sharp but short-lived spike. Chronic stress, such as ongoing work pressure, financial worry or relationship difficulties, can lead to persistently raised glucose levels over time. Both emotional and physical stress, including illness or injury, activate similar hormonal pathways, though the precise glycaemic response can vary between individuals and between type 1 and type 2 diabetes. People with type 1 diabetes in particular may experience more variable responses to psychological stress.^[2][17]

How does the body's stress response affect glucose?

Adrenaline rapidly releases stored glucose from the liver, while cortisol sustains elevated blood sugar by reducing insulin effectiveness and stimulating new glucose production via gluconeogenesis. Behavioural changes under stress, such as poor sleep and irregular eating, compound these effects.

The body's stress response raises blood sugar primarily through the release of two hormones: adrenaline (also called epinephrine) and cortisol. When the brain detects a stressor, the adrenal glands secrete these hormones as part of the well-known 'fight or flight' response. Adrenaline acts rapidly, prompting the liver to release stored glucose (glycogen) into the bloodstream within minutes.^[3] Cortisol acts more slowly but sustains elevated glucose levels over a longer period by reducing the effectiveness of insulin and stimulating the liver to produce new glucose through a process called gluconeogenesis.

Cortisol also interferes with insulin signalling in muscle and fat cells, making it harder for those tissues to absorb glucose from the blood. This combination of increased glucose production and reduced glucose uptake is what drives stress-related hyperglycaemia.

Beyond these direct hormonal effects, stress can indirectly affect blood sugar through behavioural changes. People under stress are more likely to eat irregularly, choose high-sugar or high-fat foods, reduce physical activity, and sleep poorly. Each of these behaviours independently affects glucose regulation, and together they can compound the physiological effects of cortisol and adrenaline. Alcohol can also disrupt sleep quality and contribute to glycaemic variability, though its effects on glucose depend on the amount consumed and the timing relative to meals and medication. Sleep deprivation in particular is associated with raised cortisol levels the following day, creating a cycle that can be difficult to break without deliberate intervention.^[5]

Who is most at risk from stress-related blood sugar spikes?

People with type 1 or type 2 diabetes are most at risk, as their impaired insulin response means stress-induced hyperglycaemia lasts longer. Those with prediabetes, obesity, or a family history of type 2 diabetes are also particularly vulnerable.

People with type 1 or type 2 diabetes are most at risk from stress-related blood sugar spikes, because their ability to produce or respond to insulin is already compromised. In this group, stress-induced hyperglycaemia can be more pronounced and last considerably longer than in people without diabetes, increasing the risk of both short-term symptoms and longer-term complications if it occurs repeatedly.

People with prediabetes, sometimes referred to in UK clinical settings as non-diabetic hyperglycaemia or impaired fasting glucose, are also vulnerable. Their insulin response is already less efficient, and chronic stress may accelerate the progression towards a type 2 diabetes diagnosis. Research suggests that psychological stress is associated with an increased risk of developing type 2 diabetes, though the evidence is largely observational and the precise magnitude of risk varies between studies.^[6]

Certain groups face compounding risks. Older adults may have altered cortisol rhythms and reduced insulin sensitivity, which can make them more susceptible to stress-related glucose dysregulation, though the relationship between age and cortisol is complex. People who are overweight or living with obesity may already have a degree of insulin resistance, which stress hormones can worsen. Those with a family history of type 2 diabetes, or from ethnic backgrounds with a higher genetic predisposition, may also be disproportionately affected.

People managing other long-term conditions, such as cardiovascular disease or polycystic ovary syndrome (PCOS), should be aware that stress can interact with their existing metabolic vulnerabilities. If you are in any of these higher-risk groups, monitoring your blood sugar during periods of significant stress, in discussion with your GP or diabetes care team, is a reasonable precaution.

How can you manage stress to keep your blood sugar stable?

Regular physical activity, mindfulness-based approaches and prioritising 7 to 9 hours of sleep are evidence-based strategies for reducing stress-related blood sugar rises. NHS Talking Therapies offers CBT and other support without a GP referral in most parts of England.

Managing stress effectively is a recognised component of blood sugar control. NICE guidance on type 2 diabetes management (NG28) acknowledges the role of psychological wellbeing alongside diet, physical activity and medication.^[7] Several evidence-based strategies can help reduce the physiological impact of stress on glucose levels.

Regular physical activity is one of the most effective tools available. Exercise lowers cortisol over time, improves insulin sensitivity, and helps the muscles use glucose more efficiently. Even a 20 to 30 minute brisk walk on most days of the week can make a meaningful difference. The UK Chief Medical Officers' guidelines, reflected in NHS advice, recommend at least 150 minutes of moderate-intensity activity per week for adults.^[8][9]

Mindfulness-based approaches, including mindfulness-based stress reduction (MBSR) and cognitive behavioural therapy (CBT), may help reduce stress and support glycaemic outcomes in people with diabetes, though the evidence varies in quality and effect size across studies.^[2][7] Referral to talking therapies is available through NHS Talking Therapies (formerly IAPT) without a GP referral in most areas of England.^[10] Equivalent services are available in Scotland (NHS Inform), Wales (NHS Wales) and Northern Ireland (your GP can advise on local provision).

Other practical steps include:

• Prioritising sleep: aiming for 7 to 9 hours per night helps regulate cortisol rhythms

• Eating regularly: skipping meals can compound stress-related glucose instability

• Limiting caffeine and alcohol: both can disrupt sleep and contribute to glycaemic variability

• Social connection: maintaining supportive relationships is associated with lower chronic stress

If you have type 1 diabetes or are taking an SGLT2 inhibitor (such as dapagliflozin, empagliflozin or canagliflozin), illness and physical stress increase the risk of diabetic ketoacidosis. During any period of illness or significant physical stress, follow your sick-day rules as agreed with your diabetes care team, check your blood ketone levels as advised, and seek prompt medical advice if ketones are raised or you are unable to eat or drink. Do not adjust your insulin or other diabetes medicines without first speaking to a clinician.

For those managing diabetes, keeping a blood glucose diary during stressful periods can help identify patterns and inform conversations with a healthcare professional. Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations, with prescriber review and pharmacist support, for those exploring structured approaches to metabolic health.

When should you speak to your GP about stress and blood sugar?

Speak to your GP if blood glucose readings remain consistently above your target range during stressful periods, or if you experience symptoms of hyperglycaemia such as increased thirst, fatigue or blurred vision. Call 999 immediately if you suspect diabetic ketoacidosis or hyperosmolar hyperglycaemic state.

You should speak to your GP if you notice persistently raised blood sugar readings during or after stressful periods, particularly if you have diabetes or prediabetes and your levels are not returning to your usual range within a few hours. A single stress-related spike is unlikely to cause lasting harm, but a pattern of elevated readings warrants clinical review, as it may indicate that your current management plan needs adjustment.

Contact your GP if you experience any of the following:

• Blood glucose readings consistently above your agreed target range during stressful periods, despite following your usual diet and medication routine

• Symptoms of hyperglycaemia, such as increased thirst, frequent urination, fatigue or blurred vision, that are new or worsening

• Significant low mood, anxiety or burnout that is affecting your ability to manage your diabetes or general health

• Unexplained changes in HbA1c at your routine diabetes review that coincide with a period of prolonged stress

If you do not have a diabetes diagnosis but are concerned that stress is affecting your blood sugar, your GP can arrange a fasting glucose test or HbA1c measurement to provide a clearer picture. This is particularly advisable if you have risk factors such as a family history of type 2 diabetes, a BMI above the threshold relevant to your ethnic background, or a history of gestational diabetes.

For urgent concerns, seek emergency help immediately in the following situations:

• Suspected diabetic ketoacidosis (DKA): symptoms include vomiting, rapid or deep breathing, confusion, and a fruity smell on the breath.^[14] Call 999 or go to A&E immediately.

• Suspected hyperosmolar hyperglycaemic state (HHS): this can occur in people with type 2 diabetes and may present with very high blood glucose, severe dehydration, confusion or drowsiness without significant ketones.^[15][16] Call 999 or go to A&E immediately.

For non-emergency advice outside GP hours, contact NHS 111. Suspected adverse effects from any medication can be reported via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk.

Scientific References

1. High blood sugar (hyperglycaemia).
2. Impact of chronic emotions and psychosocial stress on glycaemic control in type 1 diabetes.
3. Regulation of net hepatic glycogenolysis and gluconeogenesis (epinephrine and glucose production).
4. Role of cortisol in the metabolic response to stress hormone infusion in the conscious dog.
5. Sleep loss results in an elevation of cortisol levels the next evening.
6. Job strain and effort-reward imbalance as risk factors for type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies.
7. Type 2 diabetes in adults: management (NG28).
8. UK Chief Medical Officers' physical activity guidelines.
9. Physical activity guidelines for adults aged 19 to 64.
10. Find NHS talking therapies for anxiety and depression.
11. SGLT2 inhibitors: updated advice on the risk of diabetic ketoacidosis.
12. EMA confirms recommendations to minimise ketoacidosis risk with SGLT2 inhibitors in diabetes.
13. Diabetes, surgery and medical illness.
14. Diabetic ketoacidosis.
15. A narrative review of the diabetic ketoacidosis and hyperosmolar hyperglycemic state overlap syndrome.
16. Prevention and management of hyperglycaemic crisis. Nursing Standard.
17. Body Mass Index Effect on Differing Responses to Psychological Stress in Blood Glucose Dynamics in Patients With Type 1 Diabetes. Journal of Diabetes Science and Technology.
18. Sleep problems - Every Mind Matters.

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