When to Test Your Blood Sugar Levels Every Day If You Have Diabetes

Checking your blood sugar can feel like a major inconvenience—not to mention, if you’re using a finger-stick test, it can hurt, too. Yet, monitoring your glucose level is key for good diabetes management.

Testing your blood sugar levels, whether by finger-stick or continuous glucose monitor (CGM), is the best way to get immediate feedback on how your behaviors are impacting you, says Erin Davis, M.S., RDN, a certified diabetes care and education specialist “You’ll know exactly how your body responds to food, sleep (or lack thereof), stress and physical activity. Blood sugar data is useful for achieving your personalized goals,” she explains.

But when should you check your CGM app or take a finger-stick test? We spoke to diabetes experts to find out exactly when they recommend testing your blood sugar if you have type 2 diabetes. Being in-the-know means you can take action to better manage your glucose levels to stay in a healthy range. Blood sugar management can vary person-to-person, so it’s important to make a plan with your medical team but there are a few factors that can influence your testing needs. 

Factors That Influence How Often You Should Test Your Blood Sugar

Current Diabetes Management

How long have you had type 2 diabetes? Have your labs, such as your A1C levels, been trending in the right direction? How well your diabetes is currently being managed will affect how often your doctor recommends you monitor your blood sugar.

Oral Diabetes Medications and Insulin

If you are on medication for diabetes, it is important to check your blood sugar regularly, though how often depends on what medications you’re taking. The guidance can vary based on the type of medication you’re taking, so be sure to check in with your medical provider.

Your Lifestyle

Lifestyle factors like diet and exercise significantly impact blood sugar control and how often you should check your sugar. “Many factors can cause changes to your blood sugar, including food choices, physical activity, dehydration, medication use, stress, sickness and hormonal changes,” says Samantha Turner, M.P.H., RDN, owner of OakStone Health and Nutrition. If you’re exercising a lot or are feeling under the weather, you may be advised to check your blood sugar levels more often.

When to Test Your Blood Sugar Every Day 

If You’re Taking Oral Diabetes Medication

If you take oral medications to manage your blood sugar, check your glucose levels at least once per day, says Vandana Sheth, RDN, CDCES, a registered dietitian nutritionist and diabetes care and education specialist. The ideal time depends on when you take your medication and how well your diabetes is managed, she says, so talk to your doctor for specific guidance.

Taking your fasting blood sugar (when you wake up and on an empty stomach), before or two hours after a meal, and at bedtime are all commonly recommended testing times if you’re on oral meds. But mix these times up: “I often suggest my clients rotate the times they test their blood sugar so we can get a better idea over a week of how they are doing,” Sheth says.

If You’re on Insulin

You’ll want to test your blood glucose more frequently—as much as four or more times per day—if you’re taking insulin, Sheth says. That may include first thing in the morning, anytime you take your insulin, if you have symptoms of high or low blood sugar, in the evening before bed and even during the night. “Testing before meals will help determine how much insulin dosage is required and the pre-bedtime and nighttime tests are to ensure that the blood sugar remains stable,” she says.

In addition to creating a more structured routine for blood sugar checks if you take insulin, it’s also important to understand your body’s signs of both high and low blood sugar and be prepared to check your glucose any time you experience symptoms. 

If You Have Symptoms of High or Low Blood Sugar

So many factors can cause your blood glucose to dip too low (called hypoglycemia) or rise too high (hyperglycemia), including the protein, fat and carbs in your food, if you’re drinking alcohol, exercise and how much insulin you’re taking, says the Centers for Disease Control and Prevention. If you recognize one of these symptoms, that’s another time you want to test to see where you’re at, so you can take action, if needed. For example, if you have low blood sugar, you may eat a snack or drink orange juice to bring your levels back up. If your blood sugar is spiking after a meal, you may consider using more insulin or taking a walk to bring your levels back down.

Symptoms of low blood sugar include, per the CDC: 

• Dizziness
• Fast heartbeat
• Hunger
• Irritability or confusion
• Nervousness or anxiety
• Shaking
• Sweating

Symptoms of high blood sugar include, per the CDC: 

• Blurred vision
• Fatigue
• Increased thirst
• Increased urination

Blood Sugar Targets with Diabetes

According to the American Diabetes Association, blood sugar targets for folks with type 2 diabetes include:

• Before a meal: 80 to 130 mg/dL 
• One to two hours after the start of a meal: Less than 180 mg/dL

When to Switch Up Your Testing Schedule

Your Medication Changes

If your doctor recommends changing your medication or increasing your insulin dose, they likely will also recommend that you monitor your blood sugar more frequently to assess how well it’s working to manage your diabetes.

Stress and Sickness

Being sick causes your body to churn out hormones that raise your blood sugar, per the CDC. If you’re ill, recovering from surgery or especially stressed, you may notice elevated glucose when you test. Plus, both illness and stress can influence your eating habits—you might skip meals if you’re not hungry when ill, or reach for sugary foods when stressed—and that also affects your blood sugar.  

You Are Pregnant

If you have type 2 diabetes and become pregnant, you’ll want to keep a closer eye on your blood sugar levels. Hormonal changes during pregnancy can affect how well you can manage your diabetes, and so you’ll need to change up how often you test, according to the National Institute for Diabetes and Digestive and Kidney Diseases. Test before meals, one and two hours after eating, at bedtime and overnight.

You’re Exercising More Often

Increasing physical activity is a great way to help keep blood sugar levels in check. However, you may notice that your blood glucose levels respond differently depending on the activity and duration, the ADA also points out. For instance, your levels may decrease after a walk but temporarily increase during a high-intensity activity. That’s why it’s important to understand how your body responds, which will allow you to properly fuel before, during or after exercise, as well as adjust the timing of your medication. Testing before and after exercise can help you learn how your body responds to activity.

Tips for Effective Blood Sugar Testing

Know Your Options

Your two choices for testing your blood sugar are a blood glucose meter (which requires a finger-stick test) or a CGM. The one that’s best for you takes into account your lifestyle, preferences and insurance coverage and access. Chat with your medical provider to find out your options and learn what’s best for you. Regardless of how you test, what’s important is that you test consistently as directed by your doctor.

Clean Before Testing

If you’re using finger-stick testing, you need clean hands for accurate readings. “The most accurate results come after washing hands with soap and water—not using hand sanitizer,”  says Amanda Lane, M.S., RDN, CDCES, founder of Healthful Lane Nutrition. “Alcohol-based hand sanitizers actually disrupt the red blood cells and can give inaccurate results,” she says. Make sure you also clean your fingertip with alcohol and use a new lancet each time. Residue on your fingers can also skew results.

Watch for Patterns

Most blood sugar meters will store your blood sugar tests for you, but also consider keeping a journal or spreadsheet of your results. Seeing it on paper can help you pinpoint patterns in how factors like food, exercise, stress and sleep affect how well you can manage your blood glucose levels.

When keeping a journal or spreadsheet, Amy Brownstein, M.S., RDN, recommends recording the day and time of testing and any other information that may explain the number. “For example, if your fasting blood sugar level is high one morning, it may be helpful to note what and when you ate dinner and how you slept that night, as those factors can influence blood sugar,” she says.

Bottom Line

Checking your blood sugar regularly can help you better manage your diabetes and learn about how your lifestyle habits impact your glucose levels. Experts recommend testing at certain times, such as before meals, one to two hours after meals, before bed and during the night. How often you test depends on the medication you’re taking, if you’re on insulin and your lifestyle habits. Consult with your doctor about what’s right for you.