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 regulate blood sugar. Also known as hyperglycemia, it requires careful daily management — but illness changes everything. Fever, infection, or even a bad cold can send your blood sugar soaring, even if you’re not eating much. That’s because stress hormones like cortisol and adrenaline kick in, telling your liver to dump more glucose into your bloodstream. This isn’t just inconvenient — it’s dangerous. Without clear diabetes sick day rules, a set of practical steps to follow when you’re unwell, you risk diabetic ketoacidosis (DKA) or severe dehydration.

These rules aren’t optional. They’re your safety net. If you’re on insulin, you might need to take more — not less — when you’re sick. Skipping doses because you’re not eating can backfire badly. You still need insulin to stop your body from breaking down fat for energy, which creates dangerous ketones. Checking your blood sugar every 2 to 4 hours isn’t overkill — it’s essential. And don’t forget to test for ketones if your glucose stays above 240 mg/dL. If you’re on oral meds like metformin, your doctor may tell you to pause them if you’re vomiting or dehydrated. insulin adjustment sick day, the process of changing your insulin dose during illness based on glucose and ketone levels is a skill you need to practice before you’re sick, not during a crisis.

You don’t need fancy foods on sick days. Clear liquids like broth, sugar-free electrolyte drinks, and water keep you hydrated. If you can’t eat solid food, try applesauce, gelatin, or a small banana to avoid low blood sugar. Never assume you’re safe just because you’re not hungry. Your body is working harder, and it needs fuel — even if it’s just 15 grams of carbs every hour. Keep a log: glucose numbers, ketone results, what you ate, and your meds. This isn’t busywork — it’s data your doctor needs if things get worse. diabetic illness management, the strategy of balancing medication, hydration, and nutrition during sickness is about staying ahead, not reacting.

Know when to call for help. If your glucose stays above 300 mg/dL for more than a day, if you’re vomiting and can’t keep fluids down, or if your ketones are moderate to high, don’t wait. Head to urgent care. These rules exist because diabetes doesn’t take days off — and neither should you. Below, you’ll find real-world advice from people who’ve been there, and clear guides on how to handle every stage of illness without panic or guesswork.