Your Guide to Blood Sugar Monitoring with Type 2 Diabetes
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. Regularly testing levels and tracking numbers 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 for glucose monitoring
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 glucose monitoring, while inconvenient, is typically done to screen for hypoglycemia (low blood glucose). It is common not to feel a low blood sugar level 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 occurred unknowingly overnight.
Other important times for glucose monitoring
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 on your testing levels.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.
How blood sugar determines treatment
The 2018 standards of care in diabetes provide specific guidance:2
Most patients using intensive insulin regimens—such as multiple-dose insulin or insulin pump therapy—should perform self-monitoring of blood glucose (SMBG) at specific intervals. You should perform these checks:2
- Prior to meals and snacks
- At bedtime
- Occasionally after meals (postprandially)
- Prior to exercise
- When you suspect low blood glucose
- After treating low blood glucose, until you are normoglycemic
- Prior to critical tasks, such as driving
When prescribed as part of a broad educational program, SMBG may help to guide treatment decisions and self-management for patients taking less frequent insulin injections or non-insulin therapies.
Discuss your data 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 how to interpret your tracking 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?
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