Diabetes Sick Day Rules: What to Do When You're Ill and Blood Sugar Spikes

When you have diabetes, a chronic condition where the body struggles to manage blood sugar. Also known as hyperglycemia, it means even a simple cold can turn dangerous if you don’t follow clear sick day rules, a set of proven actions to protect your health when you’re ill. These rules aren’t optional—they’re the difference between resting at home and ending up in the ER.

When you’re sick, your body releases stress hormones like cortisol and adrenaline. These hormones fight infection but also push your liver to dump extra glucose into your bloodstream. That’s why your blood sugar, the amount of glucose in your blood can spike even if you’re not eating. You might feel worse than usual, but it’s not just the flu—it’s your body’s reaction to uncontrolled sugar. If you’re on insulin, you may need more, not less. Skipping doses because you’re not eating is a common mistake that leads to ketoacidosis, especially in type 1 diabetes. Even if you’re vomiting or can’t keep food down, you still need insulin to stop your body from breaking down fat for energy, which creates dangerous ketones.

Monitoring is everything. Check your blood sugar every 2 to 4 hours, even at night. Test for ketones if your sugar stays above 240 mg/dL or if you’re nauseous. Keep electrolyte drinks, broth, and sugar-free fluids on hand. If you can’t eat solid food, drink juice or regular soda to avoid low sugar while still fighting high sugar. Don’t stop your meds unless your doctor tells you to. Many people with type 2 diabetes on metformin or SGLT2 inhibitors need to pause those during illness because of dehydration risks. Know your personal thresholds: when to call your provider, when to go to urgent care, and what your emergency plan is. These aren’t generic tips—they’re tailored actions based on your type of diabetes, meds, and history.

There’s no one-size-fits-all fix, but the core rules are simple: stay hydrated, test often, adjust insulin if needed, and never ignore ketones. The posts below give you real-life examples—from what to pack in your sick day kit, to how to talk to your doctor about insulin tweaks, to why some diabetes meds need to be paused during infection. You’ll find clear, no-fluff advice from people who’ve been there. No theory. No guesswork. Just what works when you’re too sick to think straight.