Can Stress Increase Blood Sugar? The Science and How to Cope

Have you ever had a day where you ate simple, low-carb meals, took your prescribed medicine on time, yet still saw your blood sugar rise to 190 mg/dL? You look back at your food diary in confusion: 'I didn't eat any sugar — why is my reading high?'

The answer often lies in stress. This isn't a vague, feel-good idea — it's documented physiology. The CDC (opens in a new tab) notes that both physical and mental stress trigger the release of cortisol and adrenaline, which signal the liver to release stored glucose into the bloodstream, and that mental health and psychosocial issues can affect blood sugar just as directly as food or medication do.

The Fight-or-Flight Hormone Reaction

When you experience stress — whether it's workplace pressure, traffic congestion, a family argument, or financial worry — your brain perceives a threat. It activates your sympathetic nervous system and floods your body with stress hormones: cortisol and adrenaline. Adrenaline speeds up your heart rate and makes you more alert, while cortisol signals your liver to release stored glucose into your blood. Adrenaline also makes your cells temporarily less sensitive to insulin, so the glucose that's released has a harder time being absorbed and tends to linger in your bloodstream longer than it would on a calm day.

• Ancient survival mechanism: in primitive times, stress meant physically running from danger. Adrenaline told your liver to dump backup glucose into your blood so your muscles had immediate fuel to fight or flee.
• Modern reality: today, mental stress usually happens while you're sitting at a desk, stuck in traffic, or lying awake worrying. Your body still dumps glucose for a physical response that never comes, so it stays trapped in your bloodstream instead of being burned off.
• The cycle can feed itself: a stressful, unexplained high reading is itself stressful, which can keep cortisol elevated and delay the number coming back down.

Everyday Stress vs. Diabetes Distress

It's worth separating two related but different things. Everyday stress — a deadline, an argument, a hot commute — is temporary and tied to a specific event; it raises glucose for hours, sometimes a day or two, then settles once the trigger passes. Diabetes distress (opens in a new tab) is different: it's the ongoing emotional weight of managing a demanding condition around the clock, and it doesn't resolve when one stressful day ends. The American Diabetes Association describes it as affecting a large share of people with diabetes at some point, and it's distinct from clinical depression, though the two can overlap. If what you're feeling is less "today was hard" and more "I am tired of this in a way that doesn't go away," that's worth naming as diabetes distress rather than just stress, and worth raising with your healthcare team.

Simple Ways to Calmer Glucose Levels

1. 15-minute box breathing: inhale through your nose for 4 seconds, hold for 4, exhale for 4, hold for 4, and repeat for a few minutes. Slow, deliberate breathing signals your nervous system that the threat has passed, which helps cortisol come back down.
2. 2Short outdoor walks: a 10-minute walk in fresh air burns off some of the circulating adrenaline and glucose, and gives your mind something to do besides the stressor.
3. 3Prioritize 7-8 hours of sleep: chronic sleep deprivation keeps cortisol elevated for longer stretches, which is part of why a rough night's sleep so often shows up as a higher fasting number the next morning.
4. 4Name the stress out loud or in writing: simply labeling what's stressing you — in a note, a log entry, or to another person — has been shown to reduce the physiological stress response, not just the feeling of it.
5. 5Build in a daily buffer: even ten quiet minutes with no phone, no tasks, and no decisions gives your nervous system a chance to reset before the next demand arrives.

When a Stress-Related High Needs More Than a Walk

Most stress-driven highs are uncomfortable but not dangerous, and settle with the steps above plus your usual routine. Treat a reading differently if it's sustained at 300 mg/dL or higher, or paired with vomiting, confusion, fruity-smelling breath, or difficulty breathing — those are signs to seek urgent medical care rather than wait it out. And if stress feels less like an occasional spike and more like a constant undercurrent that's affecting your sleep, appetite, or motivation to manage your diabetes at all, that's a conversation worth having with your healthcare team rather than something to push through alone.

“Managing stress is not a luxury — it is a vital part of managing your blood sugar.”

Track your stress alongside glucose

Use Diatic to record emotional stress notes and see how calming routines help stabilize your readings.

Log a reading (opens Diatic on Google Play in a new tab)