What is Time in Range and Why is it Important?
Dec. 15 2020
If you’ve been diagnosed with type 2 diabetes, you’re probably familiar with the A1C test. It is a blood test that measures your average blood sugar level over the past two or three months.
The A1C test has been considered the gold standard by health care providers to measure blood sugar management.
But with more people with diabetes using continuous glucose monitoring (or CGM), Time in Range is becoming a more meaningful measurement. It helps you focus on the variations of your glucose levels to try and flatten out the highs and lows. If you can achieve more time in range, you’ll likely also notice an improvement in energy levels, mood, and overall quality of life.
What does Time in Range mean?
To help you manage your diabetes, your doctor has probably talked to you about keeping your glucose levels within a certain range. This range can vary from person to person. For many people with type 2 diabetes, the range may be between 70 mg/dl to 180 mg/dl, according to the American Diabetes Association. (Always consult with your health care provider about your specific range).
Time in Range (also abbreviated to TIR) is the percentage of how long your glucose value was within your target range over a 24-hour period.
For example, if you kept your glucose levels within the range set by your doctor for 12 hours in the day, your TIR is 50%. For many people with type 2 diabetes, the recommended TIR is 70% a day, or about 17 hours a day.
Why is Time in Range Important?
One challenge with the A1C test is that it is an average of your glucose levels over the past 2 to 3 months. It doesn’t provide enough information about day-to-day diabetes management.
For example, if your glucose levels swing frequently from high and low blood sugar, you may achieve an average A1C that meets your target. In other words, your A1C looks like you’ve achieved optimal blood sugar management, but the reality is your day-to-day numbers show something different.
So what does that mean for you? More time in range isn’t just another number for your doctor. It’s about feeling better and have more energy in the day. With better TIR, you might notice a difference in your mood and stress levels. You may even feel better, too – maybe it’s less stomach aches or headaches. In fact, just a 5 percent improvement in Time in Range is equal to 1 hour of feeling better on a given day. Best of all, hitting TIR targets has a big impact on your overall health outcomes, significantly reducing the chance for diabetes complications down the road.
How can you make Time in Range work for you?
It starts with having a clear understanding from your health care provider about what your specific goals are for Time in Range.
For many people with type 2 diabetes (but not all), these levels are typically set between 70-180 mg/dL. You will also want to know your health care provider’s recommendation for how long each day you should strive to be in range.
It’s recommended that for some people with type 2 diabetes, glucose levels should be within target 70% of the time.
For example, using 70% as the target TIR during a 24-hour day, you’d want your glucose levels to be between 70-180 mg/dL about 16 hours a day.
Tips for using TIR for managing type 2 diabetes
If you’re just starting off with Time in Range, start small. Armed with your CGM, watch what happens to your glucose levels after you eat snacks or meals. Do your numbers spike out of range? Make one change, either to what you eat or the order you eat it in, to see whether you can keep your numbers in range after the meal. You could even try a short walk after a meal to see whether that helps keep your numbers in range.
Another helpful tip is to focus on overnight glucose levels. If you can keep your glucose levels in range while you sleep, that’s about 8 hours in a row where you’ve achieved TIR – or 30%. Consider eliminating snacks after dinner or taking a walk after dinner to help get your numbers in range before bedtime.
Your health care provider will likely have other tips that can help you get started.