Insulin During Illness: What You Need to Know

When you're sick, your body releases stress hormones that raise blood sugar—even if you're not eating. This is why insulin during illness, the adjusted use of insulin when sick to manage rising blood glucose levels becomes critical for people with diabetes. It’s not about skipping doses or guessing. It’s about knowing how to respond when your body is under stress. Many people think if they’re not eating, they don’t need insulin. That’s a dangerous myth. Your liver keeps making glucose, and your muscles aren’t using it like normal. Without enough insulin, your blood sugar can climb fast, leading to ketoacidosis or hyperosmolar states—both medical emergencies.

Blood sugar control, the process of keeping glucose levels within a safe range during illness during sickness requires more than just checking numbers. You need a plan. Most guidelines recommend checking your blood sugar every 2 to 4 hours when you’re ill. If you’re on insulin, you may need to increase your dose—even if you’re vomiting or can’t keep food down. Sick day rules, a set of practical steps for managing diabetes when sick exist for a reason: they prevent hospital visits. These rules include staying hydrated, never stopping long-acting insulin, and knowing when to call your doctor. For example, if your blood sugar stays above 240 mg/dL for two checks in a row, or if you have ketones in your urine, you need help now. These aren’t just suggestions. They’re lifesaving actions.

Insulin dosing, the precise adjustment of insulin amounts based on illness, blood sugar, and food intake isn’t one-size-fits-all. Some people need 10% more insulin with a cold. Others need 50% more with the flu. It depends on your type of diabetes, your usual insulin sensitivity, and how severe the illness is. If you use an insulin pump, you might need to increase your basal rate. If you take multiple daily injections, you may need extra rapid-acting insulin to correct high numbers. The key is to act early. Waiting until you feel worse only makes things harder. Keep a sick day kit ready: test strips, ketone strips, electrolyte drinks, and your doctor’s contact info. Don’t wait for a crisis to prepare.

What you’ll find in the posts below are real, practical guides from people who’ve been there—how to adjust insulin during infections, what to do when you can’t eat, how to tell if you’re heading into danger, and how to avoid common mistakes. No fluff. No theory. Just what works when you’re too sick to think straight. This isn’t about being perfect. It’s about being prepared. And that’s the difference between staying home and ending up in the ER.