When you have diabetes, taking care of yourself during an illness has extra importance — even if the condition is as common as the flu or a urinary tract infection.

To avoid complications, it’s a good idea to plan ahead for how you’ll handle sick days, illnesses, and infections.

This article provides some expert guidance on:

  • how to prepare for sick days
  • how to put together a sick-day checklist
  • when to see your doctor if you have illness complications

When you have diabetes, an illness or infection can deliver a powerful one-two punch to your body. Here’s how.

Illness can make it harder to control blood sugar

One reason to plan ahead is because illness or infection can worsen diabetes symptoms.

Your body reacts to them the same way it reacts to stressful events. It produces a surge of hormones, including cortisol. Cortisol is often called the stress hormone.

When your body is flooded with cortisol, your blood sugar can spike for several reasons:

  • Cortisol prompts your body to make glucose, a type of sugar your body uses for fuel.
  • Cortisol sends a message to your pancreas to lower your insulin level.
  • Cortisol causes insulin resistance. As a result, the cells in your muscles and fat do not respond to insulin and do not take up or use as much glucose.

Both of these actions can mean that when your body is dealing with an illness or infection, you may experience a bump in your blood sugar levels.

Diabetes can complicate an illness

If you have diabetes, you may have a higher risk of certain kinds of infection or illness.

Research from 2021 shows that people with diabetes are more likely to develop certain kinds of infections, including pneumonia and cystitis (urinary tract infections).

If you do get sick, you may face a higher risk of hospitalization. For example, 2021 research associated diabetes with longer hospital stays, more complications, and a greater risk of death with COVID-19, the disease caused by the novel coronavirus.

That’s why it’s so important to work with your diabetes care team to plan ahead, so you’ll know how to handle an illness, injury, or infection if it happens. Your plan can give you some peace of mind now, and it may protect your health later on.

Advocates at the American Diabetes Association and the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) recommend that your sick-day plan address the following key questions.

What to consider when planning for sick days

  • How will you keep your blood sugar in a healthy range when you’re not feeling well?
  • How often should you test your blood sugar? What about testing for ketones?
  • Do you need to change your medication dosages?
  • Which medications should you take and which should you avoid?
  • What supplies should you keep on hand?
  • What symptoms should you watch for?
  • When should you get medical help?

Let’s tackle these questions one at a time.

Manage blood glucose when you’re sick

To prepare yourself for the sick days you’re bound to face sooner or later, talk with your diabetes care team about testing, medications, and warning signs.

When you’re sick, your blood sugar may go up for several reasons:

  • Hormones released by your immune system can raise blood sugar.
  • Being sick can change your eating and drinking habits.
  • Other medications may affect your blood glucose levels.

What to eat and drink

To keep your blood sugar in your target range, keep eating and drinking as close to your usual routine as possible. That may be easier said than done, especially if you have symptoms like nausea, vomiting, or diarrhea.

If you’re having trouble eating and drinking, aim for:

  • 4 to 6 ounces of water or sugar-free drinks every 30 minutes
  • 50 grams of carbohydrates every 4 hours, either from food or, if you aren’t able to eat solid food, from a beverage that contains some sugar

If your blood sugar is too low, you may need to follow the 15-15 rule. That means you’ll need to consume 15 grams of carbs, then test your blood sugar 15 minutes afterward.

Talk with your healthcare team about whether hard candies or glucose tablets would work if you’re not able to keep down food or drink.

When and what to test

The Centers for Disease Control and Prevention (CDC) recommends testing your blood glucose levels every 4 hours whenever you’re feeling unwell.

Keep a notepad nearby so you have an accurate record to share with your doctor. You don’t want to rely on your memory of the readings at a time when your recall could be clouded by lack of sleep or worsening symptoms.

You may also need to test your urine for ketones. Ketones are a sign that your insulin levels are low and your body is using fat for fuel.

Testing for ketones in your urine can tell you if you’re developing a condition called diabetic ketoacidosis. This condition is life threatening, so it’s important to know in advance how to detect these chemicals in your body.

The NIDDK recommends that you test ketones every 4 to 6 hours during an illness.

It’s also important to track your weight, body temperature, and blood pressure. These metrics are important clues that may tell you if:

  • You’re becoming dehydrated.
  • Your blood sugar is reaching an unhealthy level.
  • Your condition is getting worse.
  • An infection is developing.

It’s especially important for people with type 1 diabetes to test their blood glucose more often when they’re sick. Insulin levels can drop sharply as the body fights an illness or infection.

What medications to take

An illness can change how much insulin you need. Talk with your diabetes care team about when and how much to adjust your dosage of insulin and any other medications you take.

It’s important to keep taking insulin, especially long-acting insulin, on the schedule your doctor recommends. It’s also important to continue taking long-acting insulin even if you’re not eating.

Some over-the-counter (OTC) medications — especially those that treat cough, cold, and flu symptoms — contain sugar. Other types of medication can affect the way your diabetes medications work.

Your diabetes care team may be able to give you a list of medications to avoid when you’re feeling unwell with a common condition.

Build a sick-day kit

It’s a good idea to stock up on easy-to-prepare foods, sick-day drinks, medications, and diabetes care supplies so you have these items on hand for those days when you’re not feeling well. Here are some items to include in your sick-day kit:

Foods and drinks

Keep a ready supply of:

  • soups and stocks
  • popsicles or sherbet
  • crackers
  • Jell-O
  • milk or yogurt
  • fruit juice

Medical information

Your sick-day kit should also contain:

  • contact information for your doctor
  • insurance information
  • an up-to-date list of your medications

Medications and supplies

Make sure your kit is stocked with:

  • batteries for your monitoring devices
  • supplies for your glucose meter or monitor and insulin pump
  • ketone test strips
  • glucose tablets or gels
  • a 7-day supply of your glucose management medications
  • OTC cold and flu medications that don’t interfere with your blood sugar

If you’re experiencing any of the following symptoms, contact your doctor or someone on your diabetes care team right away:

  • fever over 101°F (38.3°C) for longer than 1 day
  • diarrhea for longer than 6 hours
  • vomiting more than 3 times in 24 hours
  • blood sugar higher than 240mg/dl even after taking extra insulin if recommended in your sick-day plan
  • moderate to large amounts of ketones in your urine

Diabetic ketoacidosis is a medical emergency: It can lead to coma or death. Get medical help immediately if you’re experiencing symptoms such as:

If your employer or insurer offers telehealth services, consider downloading the app or keeping contact information in your phone to make it easier to get advice if you’re not feeling well.

Diabetes can damage your immune system, according to 2020 research. For that reason, it’s important to take good care of your health year-round, not just during cold and flu season.

You can do this by:

  • eating foods that boost your immune system and keep your blood sugar in a healthy range
  • drinking plenty of water, since dehydration can raise your risk of some kinds of infections, per a 2019 study
  • resting, since sleep disorders such as obstructive sleep apnea, which sometimes overlap with diabetes, can raise your risk of health concerns
  • getting the recommended vaccines to protect yourself

The CDC recommends that people with diabetes get flu vaccines every year. It’s especially important for children, who may have more severe flu symptoms for a longer period of time than kids who don’t have diabetes.

Diabetes can make an ordinary illness more challenging — and feeling unwell can make it harder to manage your diabetes.

If you have diabetes, talk with your healthcare team to plan how you’ll respond to an illness or infection. Together, you can decide in advance how to manage your blood sugar when you’re feeling sick.

You can also stock up on food, beverages, testing supplies, and medication you might need.

A good sick-day plan includes information on which medications are safe to take, which to avoid, how best to test your blood sugar, and what steps to follow to keep diabetes or another health condition from sidelining you for longer than necessary.