How Often Should I Check My Blood Sugar?

Have you ever wondered how often to check your blood sugar and the best times of day to do it? As a diabetes educator (CDE), people often ask me both of those questions.

The frequency of blood glucose monitoring can range from a few times a week to 10 times each day. The times of day you check will depend on your current treatment plan. Checking at home allows you and your doctor to see how your treatment plan is working.^1,2

When should I check my blood sugar?

The frequency and timing of checks should depend on:

• Your current diabetes medications
• Your current sugar level
• Your risk for low blood sugar
• Your personal goals
• Insurance coverage of test strips

Key times to check your blood sugar

Your doctor may ask you to check your sugar at these times.

Fasting or before breakfast

This number helps with adjusting long-acting insulin. It also helps with some oral diabetes drugs. The American Diabetes Association (ADA) recommends a fasting level of 80-130 mg/dL.¹

1-2 hours after a meal

Knowing your number after a meal shows how food impacts your blood sugar. For those who take mealtime insulin, this shows if your dose matched your food. The ADA recommends a sugar level less than 180 mg/dL 1-2 hours after a meal.¹

Before meals

Checking at this time is helpful for those who take fast-acting insulin at meals. It shows how well your last dose matched your last meal. The ADA recommends a pre-meal level of 80-130 mg/dL.¹

Before bedtime

Knowing your number before bed helps find low blood sugar. This is vital if you take insulin or drugs that cause lows. Your doctor may ask you to eat carbs at bedtime if your sugar is low.¹

If you have a snack after dinner, check before bed. This shows how that snack changed your sugar. If it has been 1-2 hours since your snack, your sugar should be less than 180 mg/dL.¹

At 2 AM or late at night

Overnight blood glucose checks, while inconvenient, are typically done to screen for hypoglycemia (low blood glucose) as it is more common to not feel a low blood sugar overnight and to sleep through a hypoglycemia event. If you wake up with a headache or a stomach ache, it may be due to low blood sugar levels that unknowingly occur overnight.

Additional times to check blood sugar

Before, during and after exercise

Exercise often causes blood sugar to go down. If you take insulin, exercise may increase your risk for lows. Checking before, during, and after exercise helps you see the impact.¹

Before driving

Checking at this time allows you to better ensure your blood glucose is at a safe number before getting behind the wheel.

After consuming alcohol

Alcohol may increase your risk of having low blood sugar.

During illness or stress

Illness and/or stress may cause your blood glucose to be higher than average.

Blood sugar can determine treatment options

The 2018 standards of care in diabetes have recommended the following:²

• "Most patients using intensive insulin regimens (multiple-dose insulin or insulin pump therapy) should perform self-monitoring of blood glucose (SMBG) prior to meals and snacks, at bedtime, occasionally postprandially, prior to exercise, when they suspect low blood glucose, after treating low blood glucose until they are normoglycemic, and prior to critical tasks such as driving."
• "When prescribed as part of a broad educational program, SMBG may help to guide treatment decisions and/or self-management for patients taking less frequent insulin injections or noninsulin therapies."

Discuss blood sugar levels with a doctor

Speak with your doctor about how often you should check your sugar. Ask them what times of day or week to do it.

Don’t forget to ask: "What should I do with this information?" Your health will likely not improve unless you know what to do with the numbers.

If you are not sure how to use your meter, meet with a diabetes educator for training.

How often do you check your blood sugar?