Learning to measure and understand your blood sugar numbers and ranges is a key part of managing diabetes. If you’ve been living with diabetes for a while, you’re probably familiar with monitoring your blood sugar. But are you familiar with your time in range (TIR) and how to measure it?

DiabetesTeam members see the value of using TIR as a way of seeing how well they’re managing their diabetes as opposed to individual blood glucose measurements. “TIR gives me the ‘big picture’ — a single blood sugar scan at 8 a.m. means almost nothing in comparison,” noted one member.

What Does Time in Range Mean?

TIR is a measurement that tells you how much of the day your blood sugar stays within a targeted range. For most people with diabetes, the targeted range is between 70 and 180 milligrams per deciliter (mg/dL).

How To Measure Time in Range

You can measure your TIR using your continuous glucose monitor (CGM). A CGM tracks changes in your blood sugar levels around the clock. A small sensor sits just under your skin and measures glucose in the fluid between your cells (interstitial fluid).

Because CGMs collect frequent readings throughout the day and night, they give a more complete picture of your TIR than finger-stick tests alone.

You can also estimate your TIR with information from regular finger-stick blood sugar checks. However, since finger-stick tests only capture single moments in time, they don’t reflect the full ups and downs of your blood sugar levels the way a CGM does.

Why Your Time in Range Matters

Your TIR matters because it provides an overall picture of how well your diabetes is managed. Your doctor can use your TIR to help you set goals and guide treatment. By knowing your TIR data, you can stabilize your blood sugar more effectively.

Why Is Time in Range Better Than A1c?

Glycated hemoglobin, or A1c, has been the main test for measuring how well diabetes treatment works over time, but some doctors say TIR may be more reliable.

A1c is the average amount of glucose in your blood over a period of three months. Like TIR, A1c is a percentage. With A1c, a higher percentage means your average blood glucose levels have been higher.

Both TIR and A1c can tell you about your average blood sugar and help guide treatment. TIR has a few advantages compared to A1c:

• TIR is calculated by the CGM based on the blood sugar readings collected by the device. A1c must use blood tests because the test measures glucose attached to hemoglobin, a protein in red blood cells.
• Unlike A1c, TIR isn’t influenced by hemoglobin variants or anemia, which can affect A1c results.
• A1c tests don’t account for significant fluctuations (changes that go up and down) over weeks or months.
• TIR can reduce the chance of missing highs and lows because CGMs collect readings all day and night.

Target Ranges for People with Diabetes

A lower TIR is associated with a higher risk of diabetes complications, like kidney disease and diabetic neuropathy.

For most people with diabetes, doctors recommend a TIR goal of 70 percent or higher. That’s a minimum of 16 hours and 48 minutes per day in your targeted glucose range (70 to 180 mg/dL). Other recommended TIR goals for most people with diabetes are less than:

• 5 percent of the time with blood sugar over 250 mg/dL
• 25 percent of the time with blood sugar between 181 and 250 mg/dL
• 4 percent of the time with blood sugar between 54 and 69 mg/dL
• 1 percent of the time with blood sugar below 54 mg/dL

Keep in mind that not everyone will have the same TIR targets. Talk to your doctor about your TIR goals based on your health and health risks.

Factors That Influence Time in Range

Your TIR goals might be slightly different from average targets based on:

• Age
• Duration of diabetes
• Pregnancy or planning a pregnancy
• Other health conditions, such as heart or kidney disease

Your TIR goals may change at different points in your life.

How To Improve Your Time in Range

Improving your TIR starts with identifying why your glucose levels may be going above or below your target range. By increasing your TIR, you can lower your risk of diabetes complications that come from glucose fluctuations and the resulting inflammation.

Work with your doctor to find out why your glucose is fluctuating and how you can increase your TIR. Your healthcare provider might suggest:

• Adjusting your medications — Changing the dose or timing of diabetes medications like insulin might help stabilize your blood sugar and improve your TIR.
• Balancing your diet — Talk to your doctor about how much protein, carbs, and fats you include in your meals. Your doctor might also suggest changes in your eating pattern.
• Exercising — Walking and other light exercise after eating can help bring high glucose back into range.

Talk With Your Doctor

Always check with your doctor before making any changes to your diabetes management plan. Use your CGM and TIR to spot patterns and set simple goals. Bring your TIR reports to each visit so you and your doctor can adjust medicines, meals, and activity. Small changes over time can help you spend more hours in range and lower your risk of complications.

Join the Conversation

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What’s your average time in range? Let others know in the comments below.