Managing Blood Sugar on Sick Days With Diabetes

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Managing Blood Sugar on Sick Days With Diabetes

By Your Health Magazine Health Information Team

You wake up with a fever, an upset stomach, or a bad cough—and your blood sugar is suddenly much higher than usual even though you have barely eaten. Or perhaps it is falling because you cannot keep food down. These changes can be confusing, but they are common when sickness and diabetes occur together. Having a clear sick-day plan can help you respond safely and recognize when you need medical care.

Why Illness Can Change Blood Sugar

When your body fights an infection or another illness, it releases stress hormones. These hormones help provide energy for the immune response, but they can also make insulin less effective and cause blood sugar to rise. Fever, pain, inflammation, dehydration, and reduced physical activity may contribute to higher readings.

At the same time, nausea, vomiting, diarrhea, or loss of appetite can lead to low blood sugar, especially if you take insulin or a medication that can cause hypoglycemia. This means illness may push glucose either up or down, sometimes quickly.

High blood sugar can increase thirst and urination, worsening dehydration. If the body does not have enough insulin, it may begin breaking down fat and producing ketones. A dangerous buildup of ketones can lead to diabetic ketoacidosis, or DKA, which is most common in type 1 diabetes but can also occur in some people with type 2 diabetes.

Follow a Personal Sick-Day Plan

The best time to prepare for an illness is before one begins. Ask your diabetes care team for written instructions covering glucose checks, ketone testing, medications, food, fluids, and when to call for help. Recommendations differ based on diabetes type, medications, pregnancy, kidney or heart conditions, and previous episodes of severe high or low blood sugar.

Keep the plan where family members or caregivers can find it. Helpful supplies may include:

• A glucose meter, test strips, lancets, and backup batteries
• Continuous glucose monitor supplies, if used
• Blood or urine ketone testing supplies, if recommended
• Diabetes medications and insulin supplies
• Fast-acting carbohydrates for low blood sugar
• Easy-to-digest foods and sugar-free fluids
• A thermometer and a list of emergency contacts

Check expiration dates periodically. If you use insulin, discuss whether you should have glucagon available and make sure someone close to you knows how and when it is used.

Monitor More Often Than Usual

Illness can make glucose less predictable, so your care team may advise checking it more frequently than you do on an ordinary day. The Centers for Disease Control and Prevention generally recommends checking every four hours during illness, but your personal plan may call for a different schedule. Continue monitoring even if you are not eating or your glucose initially appears normal.

Write down your readings, temperature, symptoms, food and fluid intake, ketone results, and medication times. This record can help your healthcare professional understand what is happening and provide appropriate guidance.

People at risk for DKA may need to test for ketones when they are sick, when glucose is substantially above their target, or when symptoms such as nausea, vomiting, abdominal pain, unusual fatigue, or rapid breathing develop. Follow the testing thresholds and response steps provided by your diabetes team. Elevated or rising ketones require prompt professional advice.

Do Not Make Medication Changes on Your Own

A common misconception is that diabetes medicine should automatically be stopped when a person is not eating. In reality, illness often raises the body’s insulin needs. People who depend on insulin, particularly those with type 1 diabetes, generally still need basal insulin even when they cannot eat normally. Stopping insulin without guidance can increase the risk of DKA.

However, reduced food intake, vomiting, diarrhea, dehydration, and kidney problems may affect the safety of certain diabetes medicines. Some medications may need to be temporarily adjusted or held during a significant illness, while others should continue. Contact your prescribing clinician or pharmacist rather than making the decision yourself.

Before taking an over-the-counter cold, cough, pain, or stomach remedy, check with a pharmacist. Some products contain sugar or may interact with prescription medicines, affect blood pressure, or influence glucose levels.

Keep Fluids and Carbohydrates Coming In

Take frequent small sips of water or another sugar-free beverage unless a healthcare professional has placed you on a fluid restriction. Broth and other easily tolerated liquids may also help replace fluid. If vomiting makes drinking difficult, try small, frequent sips rather than a full glass at once.

If you cannot eat your usual meals, use foods that are easier on the stomach, such as soup, crackers, applesauce, toast, or cooked cereal. When glucose is low or trending downward, a beverage or food containing carbohydrates may be appropriate according to your sick-day plan. People who must limit sodium, potassium, carbohydrates, or fluids because of another medical condition should ask their care team for suitable choices.

Nausea can be caused by an infection, dehydration, medication effects, very high or low glucose, or ketones. Learn more about why diabetes may be associated with nausea and feeling sick.

Make Everyday Recovery Safer

Rest is important, but avoid strenuous exercise when you have ketones, significant dehydration, fever, or uncontrolled glucose. Exercise in the presence of ketones may make high blood sugar worse. Resume normal activity gradually as you recover and as your healthcare professional recommends.

If possible, tell a family member, friend, or coworker that you are ill. Severe high or low blood sugar can cause confusion and make it difficult to recognize danger or communicate clearly. Avoid driving if you feel weak, dizzy, drowsy, confused, or unable to concentrate.

When to Seek Care

Contact your primary care clinician, endocrinologist, or diabetes care and education specialist promptly if glucose remains outside the range specified in your plan, ketones are present, medication instructions are unclear, symptoms are worsening, or you cannot maintain normal food and fluid intake. Seek urgent or emergency care for trouble breathing, confusion, fainting, severe weakness, fruity-smelling breath, persistent vomiting or diarrhea, inability to keep liquids down, significant dehydration, severe abdominal pain, high or rising ketones, or glucose that remains dangerously high or low despite following your established plan.

Reliable general information about diabetes, testing, treatment, and complications is also available through the MedlinePlus diabetes health resource. A written plan, adequate supplies, frequent monitoring, and early communication with your healthcare team can make sickness and diabetes much safer to manage.