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Managing diabetes during illness presents unique challenges that require careful attention and proactive planning. When you become sick with any type of illness—whether it’s a common cold, flu, infection, or other medical condition—your body’s response can significantly impact blood glucose levels and overall diabetes management. Understanding how to navigate these sick days is essential for preventing serious complications and maintaining optimal health.
Understanding How Illness Affects Blood Sugar Levels
When you’re sick with the flu or another illness, your body releases hormones to fight infection, and these hormones raise blood sugar levels. They also make it hard for insulin or other medicines to lower your blood sugar. This physiological response is part of your body’s natural defense mechanism, but for people with diabetes, it creates a challenging situation that requires careful monitoring and management.
When you do get sick, your blood sugar can be hard to manage, and you may not be able to eat or drink as much as usual, which can affect blood sugar levels. Feeling sick often makes you not want to eat or drink, which, surprisingly, can lead to a higher blood sugar. This counterintuitive effect catches many people off guard—even when you’re eating less, your blood sugar can still rise significantly due to the stress hormones your body produces during illness.
When you are sick and you have diabetes your stress hormones increase and your blood sugars may rise even if you are not eating, and during sick days most people with diabetes may require more insulin. Understanding this fundamental principle helps explain why maintaining your diabetes medication regimen during illness is so critical, even when your eating patterns change dramatically.
Creating a Comprehensive Sick Day Plan
Work with your doctor to write a sick-day plan for how to help prevent high blood sugar when you’re sick, and keep your plan in a handy place, and let your family know where you keep the plan. Having a written plan prepared before you become ill eliminates confusion and uncertainty during a time when you may not be thinking clearly or feeling well enough to make complex decisions.
Your sick day plan should be personalized to your specific needs and diabetes management approach. 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). Additionally, your plan should outline how often to check your blood glucose, what foods and fluids to consume during illness, and specific medication adjustments you may need to make.
It is a good idea to make a sick-day plan before you get sick, keep sugar-free liquids and liquids with 15 grams of carbohydrates in your home, and have urine ketone test strips in your home that are not expired. Being prepared with the right supplies means you won’t need to make a trip to the pharmacy when you’re feeling your worst.
Essential Supplies for Your Sick Day Kit
Make sure you have insulin, other diabetes medicines, and easy-to-make foods, enough for several weeks or longer, and consider having medicines and supplies in your home including milk of magnesia, medicine to control diarrhea, antacid, pain reliever, thermometer, and suppositories to treat vomiting. Having these items readily available ensures you can manage common illness symptoms without compromising your diabetes care.
Stock your pantry with appropriate foods that are easy to consume when you’re not feeling well. Some examples of foods you may want on hand include sports drinks, canned soup, fruit juice or regular soda, instant cooked cereals, crackers, instant pudding, and unsweetened applesauce. These items provide necessary carbohydrates and fluids while being gentle on an upset stomach.
Medication Management During Illness
Take your diabetes medicines as usual, and keep taking your diabetes medicine, even if you vomit and have trouble eating or drinking. This is one of the most important rules of sick day management, yet it’s also one that many people struggle with. The instinct when you can’t eat is to skip your medication, but this can be dangerous.
Follow these additional steps when you’re sick even if your blood sugar is within your target range: Continue taking your insulin and diabetes pills as usual. Your body still needs insulin to process the glucose in your bloodstream, and the stress hormones released during illness mean you may actually need more medication than usual, not less.
If you are vomiting and can’t take your medicine, call your doctor, as you may need to adjust your medicines. This is a situation that requires professional medical guidance, as your healthcare provider may need to recommend alternative delivery methods or temporary adjustments to your treatment plan.
Insulin Adjustments and Special Considerations
If you take insulin, being sick may affect how much you need. People on insulin may need extra short-acting or rapid-acting insulin if blood sugar is 300 or higher, and you should contact your doctor to tell you how much insulin to take based on your blood sugars. Never attempt to make major insulin dose adjustments without consulting your healthcare team, as this requires careful calculation based on your individual circumstances.
For those using insulin pumps, vigilance is especially important during illness. If you wear an insulin pump, do not take off your pump unless you will be taking insulin shots while you are off the pump. Additionally, check regularly to ensure that insulin is flowing properly through the tubing and that there are no blockages, kinks, or disconnections that could interrupt insulin delivery.
Be careful with over-the-counter medicines, and don’t take any nonprescription medicines unless you talk to your doctor first, as many nonprescription medicines can affect your blood sugar level. Common cold and flu medications, particularly those containing sugar or decongestants, can have unexpected effects on blood glucose levels. Always read labels carefully and consult with your pharmacist or healthcare provider before taking any new medication.
Blood Glucose Monitoring During Illness
Check your blood sugar more often than usual (every 2 to 4 hours), and try to keep your blood sugar at less than 200 mg/dL (11.1 mmol/L). There may be times when you need to check your blood sugar every hour. Frequent monitoring is essential because illness can cause rapid and unpredictable changes in blood glucose levels.
Test your blood sugar every 4 hours and keep track of the results. Write down or record all your blood sugar levels, the time of each test, and the medicines you have taken. Maintaining detailed records helps you and your healthcare team identify patterns and make informed decisions about treatment adjustments. These records become especially valuable if you need to contact your doctor or seek emergency care.
Check your blood sugar every 4-6 hours, at the first sign of illness, and keep a record of your blood sugar levels and insulin dose, if you take insulin. Don’t wait until you’re feeling very sick to start monitoring more frequently—begin increased testing as soon as you notice any signs of illness, even if they seem minor.
Target Blood Sugar Ranges During Illness
While your healthcare provider will give you personalized target ranges, understanding general guidelines helps you know when to take action. 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. These elevated levels require prompt attention to prevent them from climbing into dangerous territory.
If your blood sugar readings consistently exceed your target range despite following your sick day plan, contact your healthcare provider for guidance. They may recommend temporary adjustments to your medication regimen or additional interventions to bring your levels back under control. For more information on diabetes management, visit the CDC’s diabetes resources.
Ketone Testing: A Critical Safety Measure
If you have type 1 diabetes, check your urine ketones every time you urinate. Ketone testing is a crucial safety measure that can alert you to the development of diabetic ketoacidosis (DKA) before it becomes life-threatening. If you take insulin, do a test for ketones, especially when you have high blood sugar.
If you have diabetes and you’re sick or your blood sugar is 250 mg/dL or above, you’ll need to check your blood sugar every 4 to 6 hours and check your urine for ketones. Ketone test kits are affordable and widely available over the counter to check your ketones at home, and you should also test for ketones if you have any of the symptoms of DKA.
If you have type 1 diabetes check your urine for ketones when your blood sugar is 300 or higher, and call your 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. Ketones indicate that your body is breaking down fat for energy instead of using glucose, which can lead to a dangerous buildup of acids in your bloodstream.
Understanding Ketones and Their Significance
When your cells don’t get the glucose they need for energy, your body begins to burn fat for energy, which produces ketones, which are chemicals that the body creates when it breaks down fat to use for energy, and the body does this when it doesn’t have enough insulin to use glucose, the body’s normal source of energy. When ketones build up in the blood, they make it more acidic, they are a warning sign that your diabetes is out of control or that you are getting sick, and high levels of ketones can poison the body.
Ketone testing may be used in type 1 diabetes to check for early ketoacidosis, and the ketone test is usually done using a urine sample or a blood sample. Some home blood sugar meters can also measure blood ketones. Blood ketone testing is generally more accurate than urine testing and provides real-time information about your current ketone levels, while urine testing reflects ketone levels from several hours earlier.
Recognizing Diabetic Ketoacidosis (DKA)
Diabetic ketoacidosis (DKA) develops when your body doesn’t have enough insulin to allow blood sugar into your cells for use as energy, DKA is most common among people with type 1 diabetes, and DKA is serious and can be life-threatening. People with type 2 diabetes can also develop DKA. Understanding the warning signs of DKA and knowing when to seek emergency care can be lifesaving.
Diabetic ketoacidosis symptoms often come on quickly, sometimes within 24 hours, and for some, these symptoms may be the first sign of diabetes. Diabetes-related ketoacidosis has a severe and sudden onset, it can develop within 24 hours, and if you’re vomiting, it could develop much more quickly. This rapid progression makes it essential to recognize early warning signs and take immediate action.
Early Warning Signs of DKA
Symptoms might include being very thirsty, urinating often, and feeling a need to throw up and throwing up. Symptoms can include feeling very thirsty and drinking a lot, urinating much more than normal, belly pain, and nausea or vomiting. These initial symptoms can be subtle and may be mistaken for general illness, which is why monitoring blood sugar and ketone levels is so important.
Signs of diabetic ketoacidosis include excessive thirst, polyuria, dehydration, shortness of breath and laboured breathing, abdominal pain, leg cramps, nausea and vomiting, and mental confusion and drowsiness. As DKA progresses, symptoms become more severe and unmistakable.
Advanced DKA Symptoms
If untreated, more severe symptoms can appear quickly, such as fast, deep breathing, dry skin and mouth, flushed face, and fruity-smelling breath. Fruity-smelling breath, which comes from the ketones in your blood, trouble breathing, and trouble thinking clearly are particularly concerning signs that indicate DKA has progressed significantly.
Extreme tiredness (fatigue) and lethargy that can lead to coma, and fast heartbeat (especially when standing) and other signs of fluid loss (dehydration) represent advanced stages of DKA that require immediate emergency medical intervention. It’s important to get care right away, as if it’s not treated, diabetic ketoacidosis can lead to death.
Common Triggers for DKA
Very high blood sugar and low insulin levels lead to DKA, and the two most common causes are illness (you may not be able to eat or drink as much as usual, which can make blood sugar hard to manage) and missing insulin shots, a clogged insulin pump, or the wrong insulin dose. Understanding these triggers helps you take preventive measures and recognize high-risk situations.
An infection or other illness can cause the body to make higher levels of certain hormones, such as adrenaline or cortisol, these hormones work against the effects of insulin, and pneumonia and urinary tract infections are common illnesses that can lead to diabetic ketoacidosis. The most common precipitating factors were infections (69.0%) and non-compliance to treatment (53.5%), and among various infections, people commonly presented with pneumonia (38.7%) and urinary tract infection (30.6%).
Nutrition and Hydration During Illness
Drink plenty of water to prevent dehydration. Drink at least twelve 8-ounce (oz) cups (3 liters) of fluid a day, as feeling sick often makes you not want to eat or drink, which, surprisingly, can lead to a higher blood sugar. Maintaining adequate hydration is crucial for helping your body process glucose and flush out ketones.
If you can’t eat meals, you’ll need to eat or drink about 50 grams of carbohydrates every 4 hours, and some examples include 1½ cup of unsweetened applesauce or 1½ cup of fruit juice. Even when you have no appetite, consuming some carbohydrates helps prevent your blood sugar from dropping too low while also providing your body with necessary energy.
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, and try to check their effect on your blood sugar in the same way you check how other foods affect your blood sugar. This guidance helps you balance the need for hydration and carbohydrates with blood sugar management.
Managing Nausea and 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, and if vomiting persists, contact or see your provider. Vomiting presents a particularly challenging situation because it prevents you from taking in fluids and carbohydrates while also potentially preventing you from taking oral medications.
When you have an upset stomach, try to eat small meals, try carbohydrates, and many foods have the right amount of carbohydrates (about 15 grams) for your sick-day diet. Small, frequent meals are often better tolerated than large meals when you’re feeling nauseated. Choose bland, easily digestible foods that are gentle on your stomach.
Carbohydrates are important, and if you can’t eat your usual meals, ensure that you eat or drink 15 carbs every hour. Maintaining some carbohydrate intake helps prevent your body from breaking down fat for energy, which would produce ketones and potentially lead to DKA.
When to Seek Medical Attention
Minor illnesses in people with diabetes (especially children with type 1 diabetes) can lead to very high blood sugar levels and possible emergencies, and when children are sick, watch them closely for signs that they need medical attention right away. Knowing when to call your doctor versus when to go to the emergency room can be confusing, but having clear guidelines helps you make the right decision.
Go to the emergency room right away if any of the following occurs: you’re having trouble breathing, you have ketones in your urine, or you can’t keep any liquids down for more than 4 hours, or can’t keep food down more than 24 hours. These symptoms indicate a serious situation that requires immediate professional medical intervention.
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. Any of these conditions represents a medical emergency that should not be managed at home.
Warning Signs Requiring Immediate Emergency Care
You have multiple signs and symptoms of DKA, high ketones can be an early sign of DKA, which is a medical emergency, and call 911 or go to the emergency room right away. Don’t hesitate or try to manage severe symptoms at home—DKA requires hospital treatment with intravenous fluids, insulin, and careful monitoring.
You have many symptoms of diabetic ketoacidosis including being very thirsty, urinating often, feeling a need to throw up or throwing up, belly pain, weakness or tiredness, shortness of breath, fruity-scented breath, and confusion. The presence of multiple symptoms together is particularly concerning and warrants immediate emergency care.
Additional warning signs that require immediate medical attention include persistent high blood sugar levels that don’t respond to your usual treatment, severe dehydration or dizziness, fever lasting more than a few days, difficulty breathing, chest pain, or any significant change in mental status. Trust your instincts—if something feels seriously wrong, seek medical help immediately.
Additional Monitoring During Illness
Weigh yourself every day, as losing weight without trying is a sign of high blood sugar. Unexpected weight loss during illness can indicate that your body is breaking down muscle and fat for energy because it can’t properly use glucose, which is a warning sign of inadequate diabetes control.
Check your temperature every morning and evening, as a fever may be a sign of infection. Monitoring your temperature helps you track the progression of your illness and provides important information for your healthcare provider. A persistent or high fever may indicate a bacterial infection requiring antibiotic treatment.
Keep a detailed log of all your monitoring activities, including blood sugar readings, ketone test results, temperature measurements, weight, fluid intake, food consumption, and medications taken. This comprehensive record provides valuable information for your healthcare team and helps identify patterns or concerning trends that may require intervention.
Special Considerations for Different Types of Diabetes
Type 1 Diabetes Sick Day Management
People with type 1 diabetes face particular challenges during illness because their bodies produce little to no insulin. Take your usual dose of insulin or diabetes pills, and you may need more insulin, call your doctor for adjustments. Never stop taking insulin, even if you’re not eating, as your body still needs insulin to process the glucose in your bloodstream and prevent ketone formation.
For individuals with type 1 diabetes, ketone testing is especially critical during illness. The risk of developing DKA is significantly higher in type 1 diabetes, making vigilant monitoring essential. Check ketones frequently when blood sugar levels are elevated, and contact your healthcare provider immediately if ketones are moderate or high.
Type 2 Diabetes Sick Day Management
If you don’t take insulin, continue to take your diabetes medications, even if you are sick and have been throwing up. People with type 2 diabetes who manage their condition with oral medications or non-insulin injectables still need to maintain their medication schedule during illness, though the specific adjustments may differ from those required for insulin users.
If a person with T2D takes metformin tablets, it may be necessary to temporarily stop these tablets, this is usually advised if the person has a severe infection or becomes dehydrated, and if it is necessary to stop taking metformin, then an alternative treatment needs to be put in place until the metformin treatment can be resumed. This is an important consideration, as metformin can increase the risk of a serious condition called lactic acidosis when taken during severe illness or dehydration. Always consult your healthcare provider before stopping any medication.
Preventing Complications Through Proactive Management
Discuss with your provider, before you are sick, how best to handle illnesses, and typical sick day plans are below. Proactive planning is the cornerstone of successful sick day management. Don’t wait until you’re ill to have these conversations with your healthcare team—prepare in advance so you know exactly what to do when illness strikes.
Deterrence of DKA relies on early recognition of risk factors, adherence to therapy, and effective management of underlying conditions, and patients benefit from education that emphasizes the importance of consistent blood glucose monitoring, proper insulin administration, and prompt medical evaluation for infections or other acute illnesses. Education and preparation are your best defenses against serious complications.
Clinicians should reinforce the need for individualized sick-day management plans to help patients adjust insulin doses and maintain hydration during periods of stress or illness, and patient education should also address recognition of early warning signs, including polyuria, polydipsia, fatigue, nausea, abdominal pain, or changes in mental status. Understanding these warning signs enables you to take action before a minor problem becomes a major crisis.
Building Your Support Network
If you have any of these warning signs and cannot treat them yourself, contact your health care provider right away, and make sure your family members also know the warning signs. Your family members, roommates, or close friends should be familiar with your sick day plan and know how to recognize when you need help. Provide them with your healthcare provider’s contact information and clear instructions about when to call for medical assistance or emergency services.
Consider wearing a medical alert bracelet or necklace that identifies you as having diabetes. In an emergency situation where you may be unable to communicate, this identification ensures that first responders and medical personnel understand your condition and can provide appropriate care. Keep a list of your medications, allergies, and emergency contacts in your wallet or phone.
Common Illnesses and Their Impact on Diabetes
Any intercurrent illness can cause glucose levels to rise, and the following list of such illnesses is not exhaustive: the common cold, influenza, diarrhoea and vomiting, urinary tract infection, chest infection, pneumonia, abscess, and injury (e.g. fracture). Understanding how different types of illnesses affect blood sugar helps you anticipate challenges and respond appropriately.
A sick day can be caused by a cold, flu, surgery, infection, injury, stress or dental work. Even seemingly minor procedures or stressful events can trigger the hormonal response that affects blood sugar levels. Don’t underestimate the impact of dental procedures, minor surgeries, or significant emotional stress on your diabetes management.
Infections are particularly problematic for people with diabetes because they create a vicious cycle: high blood sugar levels impair immune function, making it harder to fight off infections, while infections trigger hormonal responses that raise blood sugar even higher. This is why prompt treatment of infections and careful monitoring during illness are so important.
Recovery and Returning to Normal Management
As you recover from illness, gradually transition back to your normal diabetes management routine. Continue monitoring your blood sugar more frequently than usual for several days after your symptoms resolve, as blood sugar levels may remain unstable during the recovery period. Don’t immediately return to your pre-illness monitoring schedule—taper back gradually to ensure your levels have truly stabilized.
Resume your normal eating patterns gradually, especially if you experienced nausea, vomiting, or loss of appetite during your illness. Start with small portions of your usual foods and monitor how they affect your blood sugar. If you needed to make temporary adjustments to your medication regimen during illness, work with your healthcare provider to determine when and how to return to your standard doses.
After recovering from a significant illness or episode of poor blood sugar control, schedule a follow-up appointment with your healthcare provider. Review what happened, discuss what worked well and what didn’t in your sick day management, and update your sick day plan if necessary. Each illness provides learning opportunities that can help you manage future episodes more effectively.
Long-Term Strategies for Illness Prevention
While you can’t prevent all illnesses, you can take steps to reduce your risk and minimize their impact on your diabetes. Maintain good overall diabetes control, as people with well-controlled diabetes generally experience fewer complications during illness. Keep your blood sugar levels within your target range as much as possible, take your medications as prescribed, follow a healthy eating plan, engage in regular physical activity, and attend all scheduled medical appointments.
Stay current with recommended vaccinations, including annual flu shots, pneumonia vaccines, and COVID-19 vaccines. People with diabetes are at higher risk for complications from these infections, making vaccination particularly important. Discuss with your healthcare provider which vaccines are recommended for you based on your age, diabetes type, and overall health status.
Practice good hygiene to reduce your risk of infections. Wash your hands frequently, especially before eating and after using the bathroom. Avoid close contact with people who are sick when possible. Take care of your feet daily, as foot infections can be particularly problematic for people with diabetes. Maintain good dental hygiene and see your dentist regularly, as dental infections can also affect blood sugar control.
Resources and Support for Diabetes Management
Numerous resources are available to help you manage diabetes during illness and in everyday life. If you’re concerned about DKA or have questions about how to manage your diabetes, talk to your diabetes care team, ask them for a referral to diabetes self-management education and support (DSMES) for individual guidance, and DSMES services are a vital tool to help you manage and live well with diabetes while protecting your health.
Consider joining a diabetes support group, either in person or online, where you can connect with others who understand the challenges of managing diabetes during illness. Sharing experiences and strategies with peers can provide valuable insights and emotional support. Many hospitals, clinics, and diabetes organizations offer support groups and educational programs.
Take advantage of technology to support your diabetes management. Continuous glucose monitors (CGMs) can provide real-time blood sugar readings and alert you to dangerous highs or lows, which is especially valuable during illness when levels may be more unpredictable. Diabetes management apps can help you track blood sugar readings, medications, food intake, and symptoms, making it easier to identify patterns and share information with your healthcare team.
For comprehensive information about diabetes management and sick day guidelines, visit the American Diabetes Association website, which offers extensive resources for people with diabetes and their families. The Centers for Disease Control and Prevention also provides valuable information about diabetes prevention, management, and complications.
Conclusion: Empowering Yourself Through Preparation
Managing diabetes during illness requires vigilance, preparation, and prompt action, but with the right knowledge and tools, you can navigate sick days successfully and prevent serious complications. The key is to plan ahead—create your sick day plan before you need it, stock your sick day kit with necessary supplies, educate your family members about warning signs, and maintain open communication with your healthcare team.
Remember that illness affects everyone differently, and what works for one person may not work for another. Your sick day plan should be personalized to your specific needs, diabetes type, medication regimen, and overall health status. Don’t hesitate to contact your healthcare provider with questions or concerns—they would rather hear from you early when problems are easier to manage than deal with a crisis that could have been prevented.
By understanding how illness affects blood sugar levels, monitoring carefully, maintaining your medication regimen, staying hydrated, testing for ketones when appropriate, and knowing when to seek medical help, you can protect your health and minimize the impact of illness on your diabetes management. With preparation and knowledge, you can face sick days with confidence, knowing you have the tools and information needed to keep yourself safe.