Pain can raise blood sugar, sometimes substantially. When your body experiences pain, it launches a stress response that floods your bloodstream with hormones designed to mobilize energy, and one of the main forms of energy those hormones unlock is glucose. This connection holds for both sudden, severe pain and the grinding, day-after-day variety. The relationship also runs in both directions and involves some surprising detours through pain medications, sleep quality, and even how your cells respond to insulin over time.
The Stress Response Is the Central Mechanism
When you feel pain, your nervous system treats it as a threat. The hypothalamus signals the adrenal glands to release two categories of stress hormones: catecholamines (adrenaline and noradrenaline) and glucocorticoids (primarily cortisol). Both have a direct, measurable effect on blood sugar. Catecholamines signal the liver to break down stored glycogen into glucose and dump it into the bloodstream. Cortisol does something similar but through a slower pathway: it promotes the creation of new glucose from non-carbohydrate sources and simultaneously makes your muscle and fat cells less responsive to insulin, which means the glucose lingers in the blood longer.
This is not a subtle effect. The release of catecholamines and elevated glucocorticoid levels caused by stress enhance both the requirement for insulin and the degree of insulin resistance, raising blood sugar levels through the combined action of these hormones.1PubMed Central. Stress-Induced Diabetes: A Review The more intense the pain, the bigger the hormonal surge, and the more glucose gets released. For someone whose insulin system is already under strain, this can push blood sugar into genuinely high territory.
Acute Pain and Stress Hyperglycemia
The most dramatic examples show up in hospital settings. After major injuries or surgery, blood sugar often spikes even in people who have never had diabetes. Clinicians call this “stress hyperglycemia,” and it is common enough that trauma teams routinely watch for it. The glucose elevation is not caused by eating hospital food or missing medication; it is driven by the body’s own emergency hormones flooding the system in response to tissue damage and pain.
Stress hyperglycemia is not harmless. A study of patients recovering from orthopedic surgery found that those who developed stress hyperglycemia had roughly four times the risk of adverse events overall, more than ten times the risk of cardiovascular complications, and about six times the risk of other adverse events, even after accounting for other risk factors.2PubMed Central. Stress Hyperglycemia and Complications Following Traumatic Injuries in Individuals With/Without Diabetes: The Case of Orthopedic Surgery These elevated risks applied both to people with pre-existing diabetes and to those who had no prior blood sugar problems. The spike itself seemed to be an independent warning sign that the body was under serious physiological strain.
From an evolutionary standpoint, this reaction makes sense. Researchers have argued that stress hyperglycemia is an ancient survival mechanism: when your body anticipates needing to fight, flee, or heal damaged tissue, flooding the bloodstream with fuel improves the odds of staying alive.3PubMed Central. Stress hyperglycemia: an essential survival response! The problem is that in a modern medical context, where the threat is a surgical wound rather than a predator, that glucose spike can interfere with healing and increase infection risk. The survival mechanism designed for short emergencies becomes a liability during extended recovery.
Chronic Pain and Insulin Resistance
When pain sticks around for months or years, the blood-sugar connection shifts from acute glucose spikes to a more insidious pattern: gradually worsening insulin resistance. Chronic pain keeps stress hormones elevated at a low simmer, and over time the body’s cells become less responsive to insulin. The result is not a dramatic spike you would notice on a glucose meter after a painful episode. It is a slow drift in average blood sugar that shows up on an HbA1c test, the measure of blood sugar control over the previous two to three months.
Fibromyalgia, a chronic pain condition, offers some of the clearest evidence of this link. In one study, patients with fibromyalgia had HbA1c values averaging about 0.54 units higher than one healthy control group and 0.34 units higher than another, even after adjusting for age. Every one of the fibromyalgia patients tested for formal insulin resistance markers showed at least one abnormal value.4PubMed Central. Insulin Resistance is Associated with Central Pain in Patients with Fibromyalgia A separate analysis found very similar numbers: fibromyalgia patients averaged about 0.59 units of HbA1c higher than one control population and 0.39 units higher than another.5PLOS ONE. Is insulin resistance the cause of fibromyalgia? A preliminary report A study of non-diabetic premenopausal women with fibromyalgia confirmed the pattern, finding significantly higher HbA1c and HOMA-IR scores compared to matched controls.6Egyptian Rheumatology and Rehabilitation. Insulin resistance in non-diabetic premenopausal female patients with fibromyalgia: relation to disease characteristics
To put those numbers in perspective, a half-unit shift in HbA1c is enough to move someone from solidly normal into the prediabetic range, or from well-controlled diabetes into poorly controlled territory. These patients did not have diabetes, yet their metabolic profiles looked like they were on the road there. Some researchers have gone so far as to ask whether insulin resistance might be a driver of fibromyalgia pain rather than just a consequence, though that remains an open question.
When High Blood Sugar Makes Pain Worse
The relationship between pain and blood sugar runs in both directions, and the reverse direction is equally real. Elevated blood glucose appears to lower the threshold at which you perceive pain, meaning the same stimulus hurts more when your blood sugar is high. In a study that gave healthy volunteers a glucose infusion, researchers found a significant decrease in both the threshold at which pain was first felt and the maximum level of pain they could tolerate. Patients with diabetes were even more pain-sensitive than the non-diabetic volunteers.7PubMed. Mechanism of pain in diabetic peripheral neuropathy. Effect of glucose on pain perception in humans
This creates a vicious cycle. Pain triggers stress hormones, which push blood sugar up. Higher blood sugar then increases pain sensitivity, which generates more stress hormones, which push blood sugar up further. For someone living with chronic pain and any degree of insulin resistance, this feedback loop can become self-reinforcing in ways that are hard to break without addressing both the pain and the metabolic side at the same time.
Population-level data supports the connection from the other direction as well. A cross-sectional survey found that people with diabetes or prediabetes had roughly twice the odds of experiencing chronic pain compared to those with normal blood sugar, after adjusting for age, sex, education, cholesterol, and smoking.8PubMed Central. Association between Chronic Pain and Diabetes/Prediabetes: A Population-Based Cross-Sectional Survey in Saudi Arabia Diabetic subjects reported more lower-limb pain, back pain, abdominal pain, and neck pain than their non-diabetic counterparts. Cross-sectional data cannot tell you which came first, but it is consistent with the idea that poor glucose regulation and chronic pain amplify each other.
How Pain Medications Themselves Change Blood Sugar
When pain pushes blood sugar up and you take medication to manage the pain, you might assume the problem is solved. But many common pain treatments have their own independent effects on glucose, and those effects do not always go in the direction you would expect.
Opioid Painkillers
The picture with opioids is surprisingly complex. Most studies show that opioid stimulation raises blood glucose under normal conditions. However, in people who already have high blood sugar, such as those with type 2 diabetes, opioids can actually lower glucose levels. The body’s own endogenous opioids also respond to blood sugar: levels of beta-endorphin rise when blood glucose drops, suggesting the opioid system is woven into glucose regulation in ways that go beyond just pain relief.9PubMed Central. The Clash of Two Epidemics: the Relationship Between Opioids and Glucose Metabolism For someone without diabetes, short-term opioid use may nudge blood sugar upward. For someone with diabetes, the effects become harder to predict, especially given that obesity also alters opioid receptor sensitivity and expression.
Corticosteroid Injections
Steroid injections for joint pain, back pain, or tendon issues are one of the most reliable blood-sugar disruptors in pain medicine. A study of patients with diabetes who received steroid injections for musculoskeletal pain found that blood glucose rose significantly on the first day after injection. The spike was larger and lasted longer in patients whose HbA1c was above 7% compared to those with tighter control.10PubMed Central. Changes in Blood Glucose Level After Steroid Injection for Musculoskeletal Pain in Patients With Diabetes Another prospective study of diabetic patients receiving hand injections found that 80% experienced blood glucose elevation from baseline, with no patient still showing elevated levels beyond five days. Patients with HbA1c at 7% or higher had both higher peaks and more frequent hyperglycemic episodes during those first few days.11PubMed. Elevated Hemoglobin A1C Levels Correlate with Blood Glucose Elevation in Diabetic Patients following Local Corticosteroid Injection in the Hand: A Prospective Study
If you have diabetes and your doctor recommends a steroid injection for pain, this does not necessarily mean you should refuse it. But it does mean you should plan for more frequent glucose monitoring in the days afterward and potentially adjust your medication. Most doctors will warn you about this, but some forget, and the ones who forget tend to be the specialists treating the pain rather than the physician managing your diabetes. It is worth raising the topic yourself.
Common Anti-Inflammatory Drugs
Over-the-counter anti-inflammatory drugs like aspirin and certain prescription NSAIDs can actually push blood sugar in the other direction: down. Research has shown that some NSAIDs increase insulin release from the pancreas by blocking potassium channels in beta cells, the same cells that sulfonylurea diabetes drugs target. This effect is strong enough that NSAIDs have occasionally been reported to cause hypoglycemia, particularly in people already taking diabetes medications.12PubMed Central. Non-steroidal anti-inflammatory drugs increase insulin release from beta cells by inhibiting ATP-sensitive potassium channels For most people, the effect is small and clinically irrelevant. But if you are on a sulfonylurea or insulin and you start taking high doses of an NSAID, the combination could cause unexpectedly low blood sugar.
The Indirect Routes Through Sleep and Inactivity
Pain does not only affect blood sugar through stress hormones and medications. It also disrupts the daily habits that keep glucose levels stable, and the most important of these is sleep. Anyone who has tried to sleep through a back spasm or a throbbing joint knows that pain is one of the most effective sleep destroyers. The metabolic consequences of that lost sleep are substantial.
A systematic review of the research on sleep and insulin resistance found consistent evidence that even one night of partial sleep deprivation can measurably increase insulin resistance. Studies also showed that extending sleep duration in people who were chronically sleep-deprived improved their glucose tolerance, and that regularly sleeping fewer than six hours a night significantly elevated the risk of developing diabetes.13PubMed Central. Does Insufficient Sleep Increase the Risk of Developing Insulin Resistance: A Systematic Review When chronic pain is the reason for that short sleep, the metabolic damage compounds whatever the pain’s stress hormones are already doing.
Physical inactivity is the other major indirect pathway. Exercise is one of the strongest tools for improving insulin sensitivity, and chronic pain often makes exercise difficult or impossible. Someone with severe knee pain may stop walking for exercise. Someone with chronic back pain may avoid the gym entirely. Over months and years, the resulting deconditioning and weight gain worsen insulin resistance in ways that have nothing to do with stress hormones and everything to do with the lost protective effect of movement. The pain itself did not change the cells’ insulin sensitivity through any hormonal pathway; it simply prevented the person from doing the one thing that would have kept those cells responsive.
Can Reducing Stress and Pain Improve Blood Sugar Control?
If stress hormones are a major driver of pain-related blood sugar elevation, then reducing the stress response should help. The evidence supports this, at least modestly. An overview of systematic reviews and meta-analyses found that mindfulness-based interventions lowered HbA1c by roughly 0.3% in people with diabetes, while also reducing stress, depression, and anxiety. Four out of five pooled analyses reached statistical significance for the HbA1c reduction.14PubMed Central. The Effects of Mindfulness on Glycemic Control in People with Diabetes: An Overview of Systematic Reviews and Meta-Analyses A 12-week trial in women with type 2 diabetes found that mindfulness-based stress reduction improved both mental health measures and glycemic control indices.15PubMed Central. Evaluation of the Effects of 12 Weeks Mindfulness-Based Stress Reduction on Glycemic Control and Mental Health Indices in Women with Diabetes Mellitus Type 2
A 0.3% drop in HbA1c will not transform someone’s metabolic health on its own, but in context it is clinically meaningful. Many diabetes medications achieve reductions in the 0.5-1.0% range. Getting roughly a third of a medication-level benefit from stress reduction, with no side effects, is a genuine win, especially when the alternative is unmanaged psychological stress piling additional glucose on top of whatever the underlying disease is already doing. These interventions are not a substitute for medical treatment, but they suggest that addressing the emotional and stress-related dimensions of pain has metabolic payoffs, not just psychological ones.
Practical Monitoring for People Living With Pain
If you have diabetes or prediabetes and also live with chronic pain, the interaction between the two conditions is worth paying active attention to. A few concrete things are worth knowing:
- Pain flares can look like diet failures: If your blood sugar is unusually high and you have not changed what you ate, consider whether a pain flare might be the cause. Stress-hormone-driven glucose spikes can be confusing if you are tracking food intake carefully and expecting the numbers to match.
- Steroid injections need a plan: If you receive a corticosteroid injection for any musculoskeletal problem, monitor your blood sugar more frequently for the next three to five days. The spike is temporary but can be significant, especially if your HbA1c is already above 7%.
- Sleep matters metabolically: If pain is wrecking your sleep, treating the sleep disruption is not just about comfort; it has real implications for your glucose control. Talk to your doctor about sleep-specific interventions rather than just accepting poor sleep as an inevitable part of living with pain.
- NSAIDs can drop blood sugar: If you take a sulfonylurea or insulin and start using an NSAID regularly for pain, watch for signs of low blood sugar. The interaction is uncommon at typical doses but can be meaningful at higher ones.
People without diabetes generally do not need to worry about pain-induced blood sugar changes in their daily lives. The body’s insulin system handles the stress-hormone surges and returns glucose to normal without intervention. The exceptions are major trauma or surgery, where stress hyperglycemia can develop in anyone, and prolonged severe pain, where the chronic hormonal load may start to erode insulin sensitivity over time. For people already managing diabetes or prediabetes, pain is an underappreciated factor in glycemic control that is worth discussing with both the physician managing your blood sugar and the one managing your pain.