A diabetes sick-day plan helps you respond consistently when a cold, flu, infection, stomach illness, or another problem disrupts eating and routine. This checklist explains what to prepare, what to record, how often to check blood sugar and ketones when advised, and when symptoms require urgent medical help. It does not replace instructions from your diabetes care team or provide individualized medication changes.
Overview
Illness can affect blood sugar even when you are eating less than usual. Stress hormones may raise glucose, while vomiting, diarrhea, fever, dehydration, or reduced food intake can make blood sugar harder to predict. Some people may also develop low blood sugar if they continue medicines that increase insulin availability but cannot eat normally.
Your personal sick-day rules should be written down before you need them. Ask your diabetes clinician which readings to report, how often to test, whether and when to check blood or urine ketones, and what to do with each prescribed medicine during illness. Do not assume that a medication should be stopped, doubled, or replaced simply because you are sick. Some medicines need temporary review during dehydration or poor intake, while insulin may still be needed even when food intake changes.
Keep the plan where you and a caregiver can find it. Include your clinician's phone number, an after-hours contact, your medication list, your usual glucose targets, the type of diabetes you have, and instructions for using your meter, continuous glucose monitor, ketone supplies, glucagon, or other prescribed tools.
What to track
Use a paper log, phone note, or glucose app. Record the time as well as the result so a clinician can see the pattern rather than a single number.
- Blood sugar: Record readings according to your written sick-day plan. If you use a continuous glucose monitor, also note alerts, trend arrows, and whether the reading matches how you feel. Confirm an unexpected result with a meter when appropriate and when you have access to one.
- Ketones: People with type 1 diabetes and others who use insulin may be advised to check ketones during illness or when glucose is elevated. Follow your clinician's instructions for blood or urine testing and record the result, time, and any action you were told to take. Never ignore ketones because a glucose reading is not very high, particularly if you use a medicine in the SGLT2 inhibitor class; ask your prescriber for specific guidance before illness occurs.
- Fluids: Note whether you can keep fluids down, how often you are urinating, and whether your urine is unusually dark. Take small, frequent sips if nausea makes drinking difficult. Your care team can advise which sugar-free or carbohydrate-containing fluids fit your situation and glucose readings.
- Food and carbohydrates: Record what you are able to eat. If you cannot manage regular meals, ask in advance which easy-to-tolerate carbohydrate choices are appropriate for you. Do not force food if you are vomiting, but do not wait until you feel severely unwell to seek advice.
- Medicines: List each dose taken, missed, vomited, or delayed, including insulin and non-diabetes medicines. Record the time and reason. Contact your clinician or pharmacist for instructions rather than making repeated changes on your own.
- Symptoms and temperature: Note fever, vomiting, diarrhea, pain, breathing changes, confusion, unusual sleepiness, infection symptoms, and when they began. A brief timeline can make telephone advice safer and more efficient.
Make sure supplies are available before illness starts: glucose-testing equipment and batteries, sensors and backup supplies, ketone strips if recommended, prescribed medicines, fast-acting treatment for low blood sugar, fluids, a thermometer, and emergency contact information. Check expiration dates and keep a backup method for monitoring if a device fails.
Cadence and checkpoints
Begin your sick-day plan when symptoms start or when your glucose pattern changes unexpectedly. The exact testing schedule depends on your diabetes type, treatment, recent readings, ability to eat and drink, and clinician instructions. During illness, review your log at regular intervals rather than waiting for symptoms to become severe.
- At the first sign of illness: Check your glucose using your usual method, assess whether you can drink, and review your written medicine instructions. Tell a trusted person that you are unwell, especially if you live alone.
- During the day and overnight: Recheck as directed by your care team and respond to device alerts. People at risk for ketones should follow their individualized instructions for ketone checks. Set reminders if fatigue makes it easy to lose track.
- After vomiting, diarrhea, or a major change: Reassess hydration, glucose, symptoms, and medicines. Contact your clinician if you cannot follow the plan, cannot keep fluids down, or are unsure about a dose.
- As you recover: Continue tracking until you are eating, drinking, and taking medicines close to your usual routine and your readings are settling. Ask whether any temporary instructions should now be reversed.
Caregivers can help by checking the log, offering fluids as directed, confirming that prescribed medicines are available, and watching for changes in alertness or breathing. They should not administer an unfamiliar dose or make treatment changes without instructions.
How to interpret changes
Look for direction and context, not one isolated reading. Repeated high readings, rising readings despite following the plan, or ketones should prompt contact with your diabetes team according to the thresholds they provided. Low readings, repeated lows, or symptoms such as shaking, sweating, weakness, dizziness, or confusion also need prompt attention under your prescribed low-blood-sugar plan.
Seek urgent medical help for trouble breathing, severe weakness, new confusion, fainting, inability to stay awake, severe dehydration, persistent vomiting, severe abdominal pain, or suspected diabetic ketoacidosis. Ketones with nausea, vomiting, abdominal pain, or rapid or deep breathing are especially concerning. Call emergency services for a medical emergency rather than driving yourself. If you are unsure whether symptoms are urgent, contact an emergency service or an on-call clinician.
A reading can be misleading when a sensor is changing quickly, you are dehydrated, or the result does not match your symptoms. Follow your device instructions and use a backup meter if advised. Do not exercise to force a high reading down while you are ill or when ketones are present unless your care team specifically tells you to do so.
When to revisit
Review this diabetes sick-day plan at least every few months and whenever your treatment, devices, health conditions, or living situation changes. Revisit it after an illness, even if you managed well. Ask what worked, which supplies ran low, whether any instructions were unclear, and whether your clinician wants a different monitoring or medication plan next time.
Update the document after a new diagnosis, pregnancy, kidney or heart problems, a change in insulin or other diabetes medicines, a new continuous glucose monitor, or a change in who helps with your care. Confirm that contact numbers and prescriptions are current.
Practical next step: Create a one-page sick-day sheet today with your care team's contact details, usual targets, testing instructions, ketone guidance, medication questions, emergency symptoms, and a blank log for time, glucose, ketones, fluids, food, medicines, and symptoms. Keep one copy at home and share it with the person most likely to help you. For related tracking support, see the printable blood sugar log and review your A1C and average blood sugar information during routine follow-up—not as a substitute for sick-day advice.
