Better Me

Is Your Blood Sugar Stable? Why Glycemic Variability Matters

Eat a bagel? Your blood sugar level goes up, then down. Go for a walk? Your blood sugar level drops. Fight with your son about homework (again)? You guessed it—your blood sugar level climbs.

These fluctuations are called “glycemic variability” and are sometimes referred to as “time in range.” They happen to all of us. Mark Bridenstine, MD, an endocrinologist at Banner Health Clinic in Loveland, CO, says there are many factors that can send your blood sugar levels higher or lower:

  • The amount and type of food you eat
  • How often and how intensely you exercise
  • Your sleep patterns
  • Your stress levels
  • Any illnesses or underlying health conditions
  • Some medications

The job of regulating your blood sugar falls mostly to your liver. When you are eating or full, your liver stores sugar so your body can use it for energy later. When you are fasting, your liver releases sugar to fuel your body. So, it’s normal for your blood sugar level to fluctuate throughout the day.

When it comes to blood sugar, stable is better

Wide swings in your blood sugar levels and extreme highs and lows can cause symptoms or be harmful. “People don’t usually feel their best when blood sugars are high,” Dr. Bridenstine said. “You may notice fatigue or headaches.”

“And a low blood sugar can stop you in your tracks and force you to address it,” he said. You may feel dizzy, weak, confused, irritable, nervous, sweaty, shaky, or have a ravenous hunger sensation.

Blood sugar fluctuations are especially dangerous for people with diabetes, who need to monitor their levels. “That way, they can modify their behavior and medications in a safe and effective manner,” Dr. Bridenstine said.

How to keep your glycemic variability under control

The more you can keep your blood sugar levels within a healthy range, the better. Dr. Bridenstine recommends that you stick to a routine with your exercise, diet, and sleep. And monitor your blood sugar levels often—that way you get real-time feedback about the factors that affect your blood sugar. “Keeping a written log of the blood sugar and the factors that influence it can also go a long way to help find patterns,” he said.

With new advances in technology, you have more options and convenient ways to monitor your blood sugar levels. Wearable continuous glucose monitors, for example, can replace or reduce the number of fingerstick blood sugar checks you need to take.

Short-term and long-term measurements are both important

If you have diabetes, it’s important to measure both your glycemic variability and your A1c levels. That’s because both measurements give you important information.

Your A1c tells you your average blood sugar level over the last three months. It’s a big-picture view of how well your blood sugar is controlled. Glycemic variability shows you the highs and lows of your blood sugar in a certain timeframe. You could have good A1c levels but still have blood sugars that swing from extreme highs to extreme lows. And that’s not what you want. “It is best to not only have good overall blood sugar control, but to have reasonably low glycemic variability,” Dr. Bridenstine said.

The bottom line

For people with diabetes, it’s important to monitor your blood sugar levels, identify factors that cause highs and lows, and take steps to keep your levels more stable. Dr. Bridenstine said, “Glycemic variability is becoming recognized as an important predicator of better diabetes control and better overall health outcomes.”

Whether you’re at risk for developing diabetes or you’ve been diagnosed, monitoring your glycemic variability might be smart. Talk to your doctor about it. To find a doctor, visit

To access your risk for developing diabetes take our free risk assessment

If you’d like to learn more ways to best manage pre-diabetes and diabetes, you may want to read:

Diabetes Endocrinology Nutrition