Stress genuinely raises blood sugar. When you are under stress, your body releases hormones that push glucose into your bloodstream and make it harder for insulin to work, which is helpful in a true emergency but unhelpful when the stress is constant. A single stressful day will not change your A1C, since that number reflects two to three months of glucose. But ongoing, chronic stress can nudge your A1C upward over time, both directly through those hormones and indirectly by disrupting sleep, eating, exercise, and medication routines. The encouraging part is that stress is one of the more manageable influences on blood sugar, and the same steps that lower stress tend to support better glucose control.
How stress raises blood sugar
The link between stress and blood sugar runs through your body’s fight-or-flight response, a survival system that has not changed much since it evolved to help humans escape physical danger.
When your brain perceives a threat, whether a near-miss in traffic or a looming deadline, it triggers the release of stress hormones, chiefly cortisol and adrenaline, along with others like glucagon and growth hormone. These hormones prepare you to act by flooding your bloodstream with fuel. They prompt the liver to release its stored glucose and to manufacture new glucose, and at the same time they create temporary insulin resistance, meaning your cells take up less glucose so that more stays available in the blood for your muscles. In a genuine physical emergency, you would burn that glucose running or fighting. In modern life, the threat is usually psychological, the glucose goes unused, and blood sugar simply rises. This is a normal, built-in response, not a malfunction, but it works against you when stress becomes a daily state.
Acute stress versus chronic stress
The difference between a passing stressor and a persistent one is central to understanding the effect on A1C.
Acute stress causes a temporary rise in glucose. In someone without diabetes, insulin quickly brings it back to normal once the stressor passes. In someone with diabetes, whose insulin response is impaired, that same spike tends to climb higher and linger longer. Either way, a brief episode is just that: brief.
Chronic stress is the bigger concern. When stress hormones stay elevated week after week, blood sugar and insulin resistance stay elevated too, and that sustained pattern is what can raise A1C. Chronic cortisol excess also encourages weight gain, particularly the visceral fat around the abdomen that is closely tied to insulin resistance, which compounds the problem over time. The clearest medical illustration of cortisol’s power is Cushing’s syndrome, a condition of chronic cortisol excess that frequently causes high blood sugar and diabetes.
It is not just emotional stress
A common misconception is that only emotional stress affects blood sugar. In fact, the body mounts the same hormonal response to physical stress, and this catches many people off guard.
Illness is a leading example. An infection such as a cold, the flu, or a urinary tract infection is a physical stressor that can send blood sugar up, which is why glucose often rises when you are sick even if you are eating less. Injury, surgery, significant pain, and serious medical illness can all drive stress hyperglycemia through the same pathway. Poor sleep acts as a physiological stressor as well, raising cortisol and worsening next-day insulin resistance. And steroid medications, sometimes prescribed during illness, are notorious for raising glucose. Recognizing physical stress as a blood sugar trigger helps explain readings that might otherwise seem random.
The indirect route: how stress changes behavior
Beyond hormones, stress affects blood sugar through the choices it nudges you toward, and this behavioral pathway is often the larger real-world driver.
Under stress, people tend to reach for comfort foods that are high in refined carbohydrate and sugar, eat irregularly, exercise less, sleep poorly, and sometimes drink more alcohol. Stress also makes it easier to forget or skip medication and glucose checks. For people with diabetes, there is an additional layer: the relentless daily demands of managing the condition can produce diabetes distress or burnout, a state of feeling overwhelmed that erodes self-care precisely when it matters most. If the weight of management is wearing you down, our guide to coping with diabetes burnout offers practical support. These behavioral effects can influence A1C as much as the hormones do, and sometimes more.
So can stress actually raise your A1C?
Putting it together, the honest answer is nuanced. Because A1C averages roughly three months of glucose, no single stressful event or hard week will show up in the number. What can raise A1C is chronic, sustained stress, working through both the direct hormonal route and the indirect behavioral one.
The research supports a real connection: chronic stress, depression, and anxiety are consistently associated with worse blood sugar control in people with diabetes. Teasing apart how much of that is the direct effect of stress hormones versus the downstream effect on behavior is difficult, and the direct hormonal contribution to A1C in people without diabetes appears modest. But for day-to-day management, the practical conclusion is clear enough: persistent stress tends to make blood sugar harder to control, and it is worth addressing. For a closer look at that specific question, our companion article on whether stress can increase A1C digs into the evidence in more detail.
Managing stress to protect your A1C
The good news is that stress is modifiable, and reducing it tends to help blood sugar through both pathways at once. No single technique works for everyone, so it is worth building a small toolkit.
Regular physical activity is one of the most effective options, because it lowers stress hormones and improves mood while also lowering glucose directly. Mind-body practices such as meditation, slow deep breathing, and gentle movement can calm the stress response, and our overview of yoga and meditation for A1C covers approaches that fit easily into a routine. Protecting sleep matters more than many people realize, since consistent, adequate rest of roughly seven to nine hours lowers cortisol and improves insulin sensitivity. Social connection and, when needed, professional counseling, including cognitive behavioral therapy, can address the sources of stress rather than just the symptoms. It also helps to limit alcohol and excess caffeine, to avoid using food as a primary coping tool, and to keep up with medication and glucose monitoring during stressful stretches so problems are caught early. These stress-reduction habits fit naturally within the broader set of steps that lower A1C naturally, and during high-stress periods, checking your readings and estimating your average with an A1C calculator can help you see whether stress is affecting your control.
Handling sick days and physical stress
Because illness reliably raises blood sugar, it is worth having a plan before you need one. When you are sick, check your glucose more often than usual, since it can climb even when you are eating little. Stay well hydrated, and in general keep taking your diabetes medications unless your clinician has told you otherwise, because stopping them during illness can allow glucose to rise dangerously. People with type 1 diabetes should monitor for ketones when glucose is high during illness. Know the warning signs that call for medical care, such as persistent vomiting, very high glucose that will not come down, or signs of dehydration, and ask your care team in advance for a written sick-day plan tailored to you.
When to seek help
Reach out to your care team if stress feels unmanageable, if you notice signs of depression or anxiety such as persistent low mood, loss of interest, or trouble functioning, or if you are experiencing diabetes burnout that is affecting your self-care. It is also worth a conversation if your blood sugar runs high during an extended stressful period despite your usual routine, or if illness is pushing your glucose up and you are unsure how to respond. Mental health is a genuine part of diabetes care, and effective help is available, from counseling to structured support, so stress and mood are appropriate things to raise with your clinician rather than to shoulder alone.
Frequently asked questions
Does stress raise blood sugar?
Yes. Stress hormones like cortisol and adrenaline prompt the liver to release glucose and create temporary insulin resistance, which raises blood sugar. The effect is larger and longer-lasting in people with diabetes.
Can stress increase my A1C?
A single stressful episode will not change your A1C, but chronic, ongoing stress can raise it over time, both through hormones and by disrupting sleep, eating, exercise, and medication habits. Chronic stress, depression, and anxiety are linked to worse blood sugar control.
Why is my blood sugar high when I am sick?
Illness is a physical stressor that triggers the same hormonal response as emotional stress, raising glucose even if you are eating less. This is normal, and it is why checking more often and following a sick-day plan matter.
Does managing stress lower A1C?
Reducing chronic stress can help blood sugar through both fewer stress hormones and better self-care habits. Combined with activity, sleep, and consistent management, stress reduction is a reasonable part of improving A1C, though it works alongside rather than instead of medical treatment.
What are the best ways to manage stress with diabetes?
Regular exercise, mind-body practices like meditation and deep breathing, adequate sleep, social support or counseling, and limiting alcohol and caffeine all help. Addressing diabetes distress or burnout directly is important, and professional help is worthwhile when stress or mood feels overwhelming.
The bottom line
Stress affects your blood sugar in two ways at once: directly, through hormones that raise glucose and blunt insulin, and indirectly, through the sleep, eating, exercise, and medication habits that stress tends to derail. A rough day will not change your A1C, but chronic stress can, which makes managing it a legitimate part of diabetes care rather than an afterthought. Regular activity, better sleep, mind-body practices, social and professional support, and a plan for sick days all help keep stress from quietly raising your numbers. If stress, mood, or burnout feels like too much to handle alone, that is exactly the kind of thing worth bringing to your care team.