Checking your blood sugar, also known as blood glucose, regularly is an important part of diabetes management. Blood glucose monitoring in addition to eating healthy, getting regular physical activity, and taking your diabetes medicine and or insulin is part of the recommended treatment.
Your diabetes care team will help you decide how often and when to check your blood sugar levels.
- Those with type 1 diabetes (T1D) will often check their levels multiple times per day or wear a continuous glucose monitor.
- Recommendations for people with type 2 (T2D) vary more depending on the treatment plan.
General guidelines advise people to check their blood sugar via a finger stick before each meal and at bedtime unless they wear a continuous glucose monitor (CGM). In addition, patients on insulin are advised to check if they feel low or high before exercise or driving, or more often when they are sick or are experiencing unusual circumstances that may affect blood sugar, such as surgery.
Factors that raise blood sugar
The following factors can raise blood sugar levels.
- Too much food or eating more carbohydrates than usual, and for T1D, this can mean eating food with higher carb content without injecting extra insulin.
- Missing or skipping an insulin dose
- Not taking enough insulin or medication
- Less exercise than normal
- Illness or injury
- Menstrual periods
- Other hormones
- Other medications, such as steroids
- Injecting insulin at a site on the body where the absorption rate is slower or at a site that is overused
- A clog in the insulin pump tubing
Factors that lower blood sugar
The following factors can lower blood sugar.
- Too much insulin or medication
- More physical activity or exercise than usual; exercise makes your body more sensitive to insulin.
- Not enough food or fewer carbohydrates than planned.
- Side effects of other medications
- Alcohol, especially on an empty stomach
A glucometer or blood glucose meter (BGM) is a tool that can be used to check blood sugar levels. This meter involves pricking the fingertip with a lancet, a small needle, and placing a small drop of blood on the test strip in the blood glucose monitor.
The standard guideline for a target blood sugar range is between 70 - 140 mg/dL, but each person is different and will work with their healthcare provider on their individualized target range.
When checking your blood sugar, remember to:
- Have clean fingers. The accuracy of your results will be affected if you have food on your fingers.
- Have dry fingers if you do clean your finger first.
- Avoid leaving your blood glucose monitor in your car in direct sunlight or anywhere that gets extremely hot or cold.
- Bring your blood glucose monitor when you leave the house in case you are not feeling well and need to monitor your blood sugar levels.
Continuous Glucose Monitors (CGMs)
The technology for checking blood sugar has rapidly advanced in the past 10 years. Instead of having glucose monitors that give you periodic readings and require you to poke your finger with a needle, CGMs work by wearing a sensor just under the skin that measures the interstitial fluid (also known as tissue fluid) glucose level in real-time. These levels are relayed to a receiver, smartphone, or insulin pump that displays the readings.
There are several options when it comes to CGM products. Some of them can predict future high and low sensor glucose events anywhere from 10 minutes to up to 60 minutes in advance. If you are interested in a CGM, you should discuss it with your healthcare provider and get more information.
Good to Know: Factors Affecting Blood Glucose. (2018). Clinical diabetes : a publication of the American Diabetes Association.
Standardizing Clinically Meaningful Outcome Measures Beyond HbA1c for Type 1 Diabetes: A Consensus Report of the American Association of Clinical Endocrinologists, the American Association of Diabetes Educators, the American Diabetes Association, the Endocrine Society, JDRF International, The Leona M. and Harry B. Helmsley Charitable Trust, the Pediatric Endocrine Society, and the T1D Exchange. Diabetes Care 201.