Question 1

Why is my blood sugar high when I’m sick but not eating?

Accepted Answer

Illness increases stress hormones that stimulate liver glucose release and can increase insulin resistance. Blood sugar may therefore rise even without food.

Question 2

How often should I check blood sugar when sick?

Accepted Answer

Many sick-day plans recommend checking about every four hours, but your personal plan may require more frequent monitoring.((Centers for Disease Control and Prevention. Managing Sick Days. Updated May 15, 2024.))

Question 3

When should I check ketones while sick?

Accepted Answer

People at risk for DKA should check ketones during illness, particularly when glucose is elevated. The ADA recommends ketone monitoring during illness and especially when glucose exceeds about 200 mg/dL.((American Diabetes Association Professional Practice Committee. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1).))

Question 4

Should I stop insulin if I cannot eat?

Accepted Answer

Usually no. People who depend on insulin generally still need basal insulin even when they are not eating. Follow your individualized sick-day plan.((American Diabetes Association Professional Practice Committee. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1).))

Question 5

Can sickness cause low blood sugar too?

Accepted Answer

Yes. Eating less, vomiting, diarrhea, and some diabetes medications can cause glucose to fall. Illness can therefore cause either high or low blood sugar.((American Diabetes Association Professional Practice Committee. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1).))

Question 6

Can a cold or flu raise blood sugar?

Accepted Answer

Yes. Even common infections can trigger stress hormones that raise glucose and temporarily increase insulin needs.

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