Navigating Sick Days: Tips for Managing Blood Sugar When Unwell

Managing blood sugar levels during illness presents unique challenges for people with diabetes. When you’re sick, your body undergoes complex physiological changes that can significantly impact glucose control, making it essential to understand how to navigate these difficult periods safely and effectively. Whether you’re dealing with a common cold, the flu, or another illness, having a comprehensive sick day management plan can help prevent serious complications and keep your diabetes under control.

Understanding Blood Sugar Changes During Illness

When you’re sick with the flu or another illness, your body releases hormones to fight infection, and these hormones raise blood sugar levels. This physiological response occurs even when you’re eating less than usual or have no appetite at all, which can be confusing for many people with diabetes who expect their blood sugar to drop when they’re not eating.

The Role of Stress Hormones in Blood Glucose Regulation

During stressful situations, epinephrine (adrenaline), glucagon, growth hormone and cortisol play a role in blood glucose levels, with stressful situations including infections and serious illness. When stressed, the body prepares itself by ensuring that enough sugar or energy is readily available—insulin levels fall, glucagon and epinephrine levels rise and more glucose is released from the liver, while growth hormone and cortisol levels rise, which causes body tissues to be less sensitive to insulin, resulting in more glucose available in the bloodstream.

Cortisol elevates blood glucose concentrations by enhancing hepatic gluconeogenesis through the activation of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, utilizing free fatty acids from lipolysis and amino acids from proteolysis as substrates. Cortisol reduces glucose uptake and utilization in peripheral tissues such as skeletal muscle and adipose tissue. This dual mechanism—increasing glucose production while decreasing glucose utilization—creates a perfect storm for elevated blood sugar levels during illness.

These hormones also make it hard for insulin or other medicines to lower your blood sugar. This insulin resistance means that people with diabetes may need to adjust their medication doses during illness, even if they’re eating less than usual. The body’s stress response essentially overrides normal glucose regulation mechanisms, prioritizing immediate energy availability over long-term metabolic balance.

Why Diabetes Makes Illness More Complicated

While having diabetes does not make you more likely to get a cold or flu, it does raise your chances of getting seriously sick. High blood sugar can cause ketoacidosis in people with Type 1 diabetes and hyperosmolar hyperglycemic non-ketotic coma in people with Type 2 diabetes, and both of these conditions are very serious and can be life-threatening.

Illness and infections, as well as other forms of stress, can raise your blood glucose levels to dangerously high levels, as part of the body’s defence mechanism for fighting illness and infection, more glucose is released into the blood stream, and this can happen even if you’re off your food or eating less than usual. Meanwhile, feeling or being sick, or having diarrhoea can make your blood sugar levels drop, because you’re not absorbing food as usual. This unpredictability makes illness particularly challenging for diabetes management.

Creating Your Sick Day Action Plan

Before you get sick, decide on an action plan with your health care team. Having a written plan in place before you become ill removes the guesswork and anxiety from sick day management, allowing you to focus on recovery while maintaining safe blood sugar levels.

Essential Components of a Sick Day Plan

Your sick day management plan should be comprehensive and personalized to your specific needs. This plan should include when to call your doctor (in most cases if you are vomiting or have diarrhea more than three times over 24 hours or have had a fever over 101° for 24 hours). Beyond emergency contact information, your plan should address several key areas:

Monitoring Guidelines: How often to check your blood glucose. People with Type 1 diabetes should monitor their blood sugar and ketones every four hours, while people with Type 2 diabetes should check their blood sugar every two to four hours and check for ketones if the blood sugar is over 240mg/dl.

Medication Adjustments: How to adjust your insulin or oral medication, if you need to. This is crucial because illness often requires medication changes, and knowing the protocol in advance prevents dangerous delays in treatment.

Nutrition and Hydration: What foods and fluids to take during your illness. Having specific guidelines about what to eat and drink when you’re feeling unwell takes the guesswork out of sick day nutrition.

Ketone Testing: If and when you need to check for ketones. Ketone monitoring is particularly important for people with Type 1 diabetes but may also be necessary for those with Type 2 diabetes during severe illness.

Over-the-Counter Medications: Discuss what over the counter medications you should use for colds, flu, etc., as some can raise your blood glucose or affect your usual medications.

Work with your doctor to write a sick-day plan for how to help prevent high blood sugar when you’re sick, keep your plan in a handy place, and let your family know where you keep the plan. This ensures that even if you’re too ill to manage your diabetes independently, someone can step in and follow your established protocol.

Assembling Your Sick Day Kit

Preparation is key to successful sick day management. Make sure you have insulin, other diabetes medicines, and easy-to-make foods, enough for several weeks or longer. Your sick day kit should include:

Blood glucose meter with extra test strips and batteries
Ketone testing supplies (urine strips or blood ketone meter)
All current diabetes medications with backup supplies
Fast-acting glucose sources for treating low blood sugar
Thermometer for monitoring fever
Sugar-free beverages and electrolyte drinks
Easy-to-digest foods with known carbohydrate counts
Contact information for your healthcare team
Written sick day plan and medication adjustment guidelines
Anti-nausea medication if prescribed by your doctor

Talk with your doctor about a prescription for anti-nausea/antiemetic medication like ondansetron (Zofran) to have on hand for sick days. Having this medication available can prevent vomiting from escalating into a medical emergency.

Blood Sugar Monitoring During Illness

Your doctor may ask you to test your blood sugar more often when you’re sick, because when your body releases hormones to fight the illness, it can also raise your blood sugar levels. Increased monitoring frequency is one of the most important aspects of sick day management, as it allows you to detect dangerous trends before they become emergencies.

How Often to Check Blood Sugar

Check your blood sugar more often than usual (every 2 to 4 hours). Test your blood sugar every 4 hours and keep track of the results. For more severe illnesses, you may need to check even more frequently. There may be times when you need to check your blood sugar every hour.

Write down or record all your blood sugar levels, the time of each test, and the medicines you have taken. This record becomes invaluable if you need to contact your healthcare provider or seek emergency care, as it provides a clear picture of how your blood sugar has been trending throughout your illness.

Weigh yourself every day, as losing weight without trying is a sign of high blood sugar. Unexplained weight loss during illness can indicate that your body is breaking down fat and muscle for energy because glucose isn’t getting into your cells properly—a dangerous situation that requires immediate medical attention.

Target Blood Sugar Ranges During Illness

Try to keep your blood sugar at less than 200 mg/dL (11.1 mmol/L). While this target may be higher than your usual goals, it represents a balance between preventing dangerously high blood sugar and avoiding hypoglycemia when you’re not eating normally.

If your blood sugar level is higher than the level your doctor recommends (for example, 240 mg/dL), drink extra liquids that don’t contain sugar, such as water or sugar-free cola. Staying hydrated helps your kidneys flush excess glucose from your bloodstream and prevents dehydration, which can worsen hyperglycemia.

Understanding and Testing for Ketones

If you take insulin, being sick may affect how much you need, and if your body doesn’t have enough insulin, it starts breaking down fat as fuel, which produces a byproduct called ketones. Ketones are acids that accumulate in the blood and urine when the body burns fat instead of glucose for energy. While small amounts of ketones are normal during fasting or low-carbohydrate eating, high levels are dangerous.

When to Test for Ketones

Do ketone testing if needed, and if you take insulin, do a test for ketones, especially when you have high blood sugar. If you have type 1 diabetes check your urine for ketones when your blood sugar is 300 or higher. If you have type 1 diabetes it’s important to check ketone levels if your blood sugar levels are above your target range (usually above 14mmmol/l) and as advised by your healthcare team.

If you have type 1 diabetes, check your urine ketones every time you urinate. This frequent monitoring during illness is crucial for people with Type 1 diabetes because ketone levels can rise rapidly, potentially leading to diabetic ketoacidosis (DKA).

Understanding Diabetic Ketoacidosis (DKA)

When your body doesn’t make enough insulin, cells can’t turn glucose into energy, and in response, your body will start to break down fat as fuel, a process that can cause a harmful buildup of acids (ketones) in the blood. Dangerous levels of ketones can cause the blood to become acidic, creating a life-threatening medical emergency known as diabetic ketoacidosis (DKA).

DKA most commonly affects people with type 1 diabetes, but the condition can occur in people with type 2 diabetes who have a severe illness or infection. This is why ketone monitoring during illness is important for all people with diabetes, not just those with Type 1.

Call you doctor, if you have moderate to high ketones in your urine or high blood sugars over 300 on two tests in a row that does not respond to insulin and fluids. Early intervention is critical for preventing DKA from progressing to a life-threatening emergency.

Medication Management During Illness

One of the most common and dangerous mistakes people with diabetes make when sick is stopping their diabetes medications. Take your diabetes medicines as usual, and keep taking your diabetes medicine, even if you vomit and have trouble eating or drinking.

Why You Must Continue Diabetes Medications

When you are sick you still need to take your medicine, and even if you are throwing up, do not stop your medicine unless your provider tells you not to take it. The body makes extra glucose (sugar) when you are sick. This means that even if you’re not eating, your blood sugar can still rise dangerously high without your medications.

Even if you are not eating as much, your blood sugar can still get very high. This counterintuitive fact surprises many people with diabetes, but it’s a critical concept to understand. The stress hormones released during illness cause your liver to release stored glucose and create new glucose, independent of food intake.

When Medication Adjustments Are Needed

If you are vomiting and can’t take your medicine, call your doctor, as you may need to adjust your medicines. If you cannot eat your normal amount of carbohydrates, use your sick day plan or contact your provider, as you may need to make a change in your insulin dose or in the dose of your diabetes pills or other injections, and you may also need to do this if your illness is making your blood sugar higher than normal.

Fevers and infections can mean you may need more insulin, even if you are eating very little. Insulin may need to be increased or decreased when you’re unwell, talk to your diabetes team for further advice on how to manage your insulin doses during illness. This is why having a sick day plan with specific medication adjustment guidelines is so important—it allows you to make safe changes without delay.

Take your usual dose of insulin or diabetes pills, though you may need more insulin, so call your doctor for adjustments. Never attempt to make significant medication changes without guidance from your healthcare team, as both high and low blood sugar can be dangerous during illness.

Over-the-Counter Medication Considerations

Be careful with over-the-counter medicines, don’t take any nonprescription medicines unless you talk to your doctor first, as many nonprescription medicines can affect your blood sugar level. Many medicines can affect your blood sugar level.

Some antibiotics can lower blood sugar levels in people with Type 2 diabetes, while decongestants and products to treat colds can increase your blood sugar level and blood pressure. Cold medications often contain sugar or ingredients that raise blood sugar, making it essential to read labels carefully and consult with your pharmacist or healthcare provider.

Always check the label for sugar before you buy them, tell the pharmacist your medical problems (diabetes, hypertension, etc.) and ask for help to find sugar-free medicine. Pharmacists are valuable resources who can help you select appropriate over-the-counter medications that won’t interfere with your diabetes management.

Nutrition and Hydration Strategies for Sick Days

Maintaining adequate nutrition and hydration during illness is challenging but essential for diabetes management. Your body needs fuel to fight infection, and dehydration can worsen blood sugar control and lead to serious complications.

Staying Hydrated

One thing to keep in mind is to be sure you’re getting enough water—so drink plenty of it, and if you’re having trouble keeping water down, have small sips every 15 minutes or so throughout the day. Drink plenty of water to prevent dehydration.

Drink plenty of sugar-free fluids to keep your body from getting dried out (dehydrated), drinking at least twelve 8-ounce cups (3 liters) of fluid a day. This may seem like a lot, especially when you’re feeling unwell, but adequate hydration is crucial for helping your kidneys clear excess glucose and preventing dehydration-related complications.

Having a temperature or being sick can lead to dehydration, and in some cases, severe dehydration and very high blood sugar levels can mean that you need to go into hospital. Dehydration creates a vicious cycle with high blood sugar—elevated glucose causes increased urination, which leads to dehydration, which in turn makes blood sugar even harder to control.

Prevent dehydration by drinking plenty of fluids, including water and caffeine free, sugar free beverages. Good options include water, sugar-free sports drinks, clear broth, herbal tea, and diet soda. Avoid caffeinated beverages, as caffeine can contribute to dehydration.

What to Eat When You’re Sick

Try to eat your normal types and amounts of food. Try to eat as you normally would. Maintaining your regular eating pattern helps keep blood sugar more stable and provides your body with the nutrients it needs to fight illness.

However, when you can’t eat your usual meals, you need a backup plan. A general guideline is to try to eat or drink 50 grams of carbohydrate every 3 to 4 hours. If you can’t eat meals, you’ll need to eat or drink about 50 grams of carbohydrates every 4 hours, with some examples including 1½ cup of unsweetened applesauce or 1½ cup of fruit juice.

You may also eat food that’s gentle on your stomach, such as bananas, rice, crackers, gelatin, or applesauce. These bland, easily digestible foods are less likely to upset your stomach while still providing the carbohydrates your body needs.

Eat small meals often. When you’re feeling nauseated or have a poor appetite, eating smaller amounts more frequently can be easier to tolerate than three large meals. This approach also helps maintain more stable blood sugar levels throughout the day.

Managing Low Blood Sugar During Illness

Having simple carbs handy like regular soda, Jell-O, or popsicles will help keep your blood glucose up if you are at risk for lows. If your blood sugar is less than 100 mg/dL (5.5 mmol/L) or falling quickly, it is OK to drink fluids that have sugar in them.

While high blood sugar is more common during illness, low blood sugar can also occur, especially if you’re vomiting, have diarrhea, or can’t keep food down. Having quick-acting carbohydrate sources readily available ensures you can treat hypoglycemia promptly, even when you’re feeling too ill to prepare food.

Special Considerations for Vomiting

If you throw up, do not drink or eat anything for 1 hour, rest but do not lie flat, and after 1 hour, take sips of soda, such as ginger ale, every 10 minutes. This gradual reintroduction of fluids gives your stomach time to settle while preventing dehydration.

Nausea and vomiting complicate T1D management, and if you or your loved one can’t keep food down or is vomiting, immediately contact the diabetes care team or seek emergency medical care. Persistent vomiting is particularly dangerous for people with diabetes because it prevents you from taking oral medications and maintaining adequate hydration and nutrition.

Monitoring Other Vital Signs

Blood sugar isn’t the only number that matters during illness. Monitoring other vital signs helps you and your healthcare team assess the severity of your illness and determine whether you need additional medical intervention.

Temperature Monitoring

Check your temperature every morning and evening, as a fever may be a sign of infection. Check your temperature every four hours and continue to monitor until you feel better. Fever indicates that your body is fighting an infection, which typically means your blood sugar will be more difficult to control and you may need medication adjustments.

Recording your temperature along with your blood sugar readings provides valuable information for your healthcare provider. A persistent or high fever, especially one over 101°F lasting more than 24 hours, requires medical attention.

Keeping Detailed Records

Use your sick day record to record your blood sugars, urine ketones, temperature, and your symptoms, and also include what you have had to eat and what medicine you have taken. This comprehensive record serves multiple purposes: it helps you track trends, provides essential information if you need to contact your healthcare provider, and ensures continuity of care if you need emergency treatment.

Your sick day record should include:

Date and time of each entry
Blood glucose readings
Ketone test results (if applicable)
Temperature readings
Medications taken (including doses and times)
Food and fluid intake (with carbohydrate counts)
Symptoms experienced
Any changes in your condition

When to Seek Medical Help

Waiting too long to get medical care when you are sick can lead to getting much sicker, and when you have diabetes, a delay in getting care can be life threatening. Knowing when to contact your healthcare provider versus when to go directly to the emergency room can literally save your life.

When to Call Your Healthcare Provider

Contact your healthcare provider if you experience any of the following:

If you have blood sugar levels under 70 mg/dl for two readings in a row and you have symptoms.
If you have an upset stomach, vomiting, or diarrhea for more than four to six hours.
If you have a temperature of 101 or more for more than 24 hours.
If you have dry mouth, thirst, decreased urination and dry, flushed skin.
If you have pain that does not go away.
If you are sick for more than two days.
If you are not sure about something.

Minor illnesses in people with diabetes (especially children with type 1 diabetes) can lead to very high blood sugar levels and possible emergencies, so when children are sick, watch them closely for signs that they need medical attention right away. Children with diabetes require especially vigilant monitoring during illness, as they can deteriorate more rapidly than adults.

Emergency Warning Signs

Go to the emergency room right away if any of the following occurs: you’re having trouble breathing, you have ketones in your urine, you can’t keep any liquids down for more than 4 hours or can’t keep food down more than 24 hours, you lose 5 pounds or more during the illness, your blood sugar is lower than 60 mg/dl, or you have vomiting and/or severe diarrhea for more than 6 hours.

These symptoms indicate serious complications that require immediate medical intervention. Don’t wait to see if they improve on their own—seek emergency care immediately. Being sick and/or having a low blood sugar level can cause fatigue or difficulty thinking clearly, so if needed, have someone else call your doctor or take you to the emergency room to avoid unsafe driving.

If you go to the emergency room be sure to tell them you have diabetes and take the above information with you. Bringing your sick day records and medication list ensures that emergency room staff have all the information they need to provide appropriate care quickly.

Special Considerations for Different Types of Illness

Different illnesses affect diabetes management in different ways. Understanding these variations helps you anticipate challenges and adjust your management approach accordingly.

Common Colds

You may not see much impact on your blood-glucose levels, though more severe colds could lead to high blood sugar. If you’re lying low on the couch, the decrease in physical activity can also call for a bit more insulin. Even mild illnesses can affect blood sugar through reduced activity levels, so continue monitoring closely even if you don’t feel very sick.

Stomach Viruses and Respiratory Infections

Infections of any kind can lead to high glucose levels. Stomach viruses present particular challenges because nausea and vomiting make it difficult to maintain adequate nutrition and hydration while also preventing you from taking oral medications. Respiratory infections like the flu often cause high fevers, which significantly increase stress hormone levels and blood sugar.

Other Stressful Events

A sick day can be caused by a cold, flu, surgery, infection, injury, stress or dental work. Your sick day plan isn’t just for infectious illnesses—any physical stress on your body can trigger the same hormonal responses and blood sugar changes. This includes surgical procedures, dental work, injuries, and even significant emotional stress.

Prevention Strategies

While you can’t prevent all illnesses, you can take steps to reduce your risk and minimize the impact when you do get sick.

Vaccinations

You’ll also want to be sure to get your annual flu shot to make getting the flu less likely. Be sure to get a flu shot every year, the flu can be dangerous, and ask your provider if you should get a pneumonia shot. Vaccinations are particularly important for people with diabetes because they’re at higher risk for complications from infectious diseases.

In addition to annual flu vaccines, discuss with your healthcare provider whether you should receive pneumonia vaccines, COVID-19 vaccines and boosters, and other recommended immunizations. These preventive measures can significantly reduce your risk of serious illness.

General Health Practices

Maintaining good overall health makes you more resilient when illness does strike. This includes:

Keeping your blood sugar well-controlled when you’re healthy
Getting adequate sleep regularly
Eating a balanced, nutritious diet
Staying physically active
Managing stress effectively
Practicing good hand hygiene
Avoiding close contact with people who are sick
Attending all scheduled medical appointments

Wear a medical alert bracelet or have information with you at all times that you have diabetes. This simple precaution ensures that if you become seriously ill and unable to communicate, emergency responders and healthcare providers will know you have diabetes and can provide appropriate care.

The Importance of Family and Caregiver Involvement

You might want to give this information to a friend or family member, so they can help you if you get sick. When you’re seriously ill, you may not be able to manage your diabetes independently. Having someone who understands your sick day plan and can help implement it is invaluable.

Make sure your family members or caregivers know:

Where you keep your sick day plan and supplies
How to check your blood sugar and ketones
What medications you take and when
Warning signs that require immediate medical attention
Contact information for your healthcare team
Your insurance information and medical history

Make sure your family members also know the warning signs. Family members should be able to recognize symptoms of both high and low blood sugar, as well as signs of diabetic ketoacidosis or other serious complications. This knowledge enables them to seek help on your behalf if you’re too ill to recognize the danger yourself.

Managing Stress and Mental Health During Illness

Being sick is stressful, and that stress can further complicate blood sugar management. The psychological stress of illness adds to the physical stress, creating additional challenges for glucose control.

Don’t panic – contact your diabetes team who will help you if you have any queries or if you are unsure about what to do. Remember that your healthcare team is there to support you. Don’t hesitate to reach out with questions or concerns—it’s always better to ask than to guess when it comes to diabetes management during illness.

Having a plan for sick days ahead of time will help you manage your diabetes and will make additional complications less likely. The confidence that comes from having a solid plan in place can reduce anxiety and help you focus on recovery rather than worrying about your diabetes management.

Long-Term Implications and Recovery

Even after you start feeling better, continue monitoring your blood sugar closely for several days. The stress hormones that elevated your blood sugar during illness don’t immediately return to normal levels once you recover. Your blood sugar may remain elevated or unpredictable for a few days after your symptoms resolve.

Gradually return to your normal eating pattern and activity level as you recover. Sudden changes can cause blood sugar fluctuations, so ease back into your regular routine. Continue checking your blood sugar more frequently than usual until your readings stabilize at your typical levels.

After recovering from illness, schedule a follow-up appointment with your healthcare provider to review how your sick day plan worked. Discuss what went well and what could be improved for next time. This debriefing helps refine your plan and ensures you’re even better prepared for future illnesses.

Additional Resources and Support

Managing diabetes during illness doesn’t have to be overwhelming when you have the right resources and support. Several organizations provide valuable information and assistance for people with diabetes:

The American Diabetes Association (diabetes.org) offers comprehensive resources on sick day management, including downloadable sick day plans and educational materials. Their website provides evidence-based information on all aspects of diabetes care.

The Centers for Disease Control and Prevention (cdc.gov/diabetes) provides public health information about diabetes management, including guidelines for managing sick days and preventing complications.

Diabetes UK (diabetes.org.uk) offers detailed sick day rules and management strategies, particularly useful for understanding international perspectives on diabetes care.

Many hospitals and medical centers also offer diabetes education programs where certified diabetes educators can help you develop personalized sick day plans and teach you the skills you need to manage your diabetes during illness. These programs often include hands-on training in blood sugar monitoring, ketone testing, and medication adjustment.

Online diabetes communities and support groups can also provide valuable peer support and practical tips from others who have navigated sick days with diabetes. While these communities shouldn’t replace professional medical advice, they can offer emotional support and practical insights based on lived experience.

Conclusion

Managing blood sugar during illness requires preparation, vigilance, and a willingness to seek help when needed. The physiological changes that occur during illness—particularly the release of stress hormones that raise blood sugar and reduce insulin effectiveness—create unique challenges for people with diabetes. However, with a comprehensive sick day plan, appropriate supplies, and knowledge of warning signs, you can navigate these challenges safely.

The key principles of sick day management include continuing your diabetes medications even when you can’t eat normally, monitoring blood sugar and ketones more frequently, maintaining adequate hydration, consuming appropriate amounts of carbohydrates, and knowing when to seek medical help. These strategies work together to prevent dangerous complications like diabetic ketoacidosis and hyperosmolar hyperglycemic state while supporting your body’s ability to fight illness.

Remember that preparation is your best defense against sick day complications. Work with your healthcare team before you get sick to develop a personalized sick day plan, assemble a sick day kit with all necessary supplies, and ensure your family members know how to help if needed. This proactive approach transforms sick days from potential emergencies into manageable challenges.

Finally, never hesitate to contact your healthcare provider when you’re unsure about how to manage your diabetes during illness. It’s always better to ask questions and seek guidance than to wait until a minor illness becomes a serious complication. Your healthcare team is your partner in diabetes management, and they want to help you stay safe and healthy, especially during the vulnerable period of illness.

By understanding how illness affects blood sugar, preparing in advance, and following your sick day plan, you can successfully manage your diabetes through colds, flu, and other illnesses while minimizing the risk of complications and supporting your body’s natural healing processes.

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