Skip to Main Content

Living with Diabetes: How to Monitor Your Blood Sugar Levels

September 8, 2022

More than 34 million Americans have diabetes, meaning their bodies either do not produce insulin or can’t use it properly. (Insulin is a hormone that helps the cells in our bodies absorb the glucose [sugar] in our blood, which we use for energy.) 

Over time uncontrolled diabetes can lead to a host of serious health issues, so it’s important for those with diabetes to keep their blood sugar levels in a healthy range—meaning it’s neither too low nor too high. There are a number of ways to monitor blood sugar. 

One method measures fasting blood sugar, which means testing your blood a half-hour before eating. This can be done with a glucometer, a small machine that comes with small needles (to poke your finger to get a droplet of blood) and test strips. Within a few seconds, the glucometer reveals your blood sugar level, which ideally should be between 80 and 130 milligrams per deciliter.

If your blood sugar level is low—that is, less than 70, that means you are hypoglycemic, and Carolyn Gonzalez, MD, a Yale New Haven Hospital resident, recommends what’s called the “15-15 rule.” This means taking in approximately 15 grams of carbohydrates, which could be a half-cup of juice, a couple of hard candies, or even a tablespoon of sugar, corn syrup, or honey. Then, wait 15 minutes and test your blood sugar again. If it’s still low, repeat the drill. 

“If you consistently have low blood sugar, it's probably time to go to the hospital. If you have uncontrolled diabetes, there can be a lot of complications that can accompany it,” Dr. Gonzalez says. 

Another method for measuring blood sugar is what’s called the hemoglobin A1C test, which measures your average blood sugar levels over the course of about three months. These tests are typically done in a doctor’s office two to four times a year. 

“For most people, your hemoglobin A1C goal is less than 7%, but sometimes if you're an older person or have other illnesses, an appropriate goal might be less than 8%,” Dr. Gonzalez says. 

In this video, Dr. Gonzalez and a colleague discuss additional points about monitoring your diabetes.