If you use a continuous glucose monitoring (CGM) system such as Medtronic Guardian, FreeStyle Libre, or Dexcom, you’ve likely encountered the term Time in Range (TIR). Around 2.4 million Americans now use CGM technology at home, and to benefit fully from these devices, it’s essential to understand the data they provide. TIR has become one of the most modern and valuable methods for evaluating glucose control.
Diabetes is a progressive and complex condition that can impact almost every body system. To maintain steady glucose levels and better manage the disease, it is essential to work with your healthcare team to identify your individual TIR goals. But what exactly does Time in Range measure—and why does it matter?
What Is Time in Range?
Time in Range (TIR) is the percentage of time your blood glucose is within your target range. On a CGM device, this is often shown as a green “target” zone. Your goal is to spend as much time as possible within that zone.
Maintaining glucose within range can help reduce the risk of major diabetes-related complications such as heart disease, kidney damage, nerve problems, vision loss, and sexual dysfunction. It can also support better energy levels, improved mood, and overall well-being.
Why Time in Range Matters
Hypoglycemia—low blood sugar—is one of the biggest concerns for people with diabetes. It can occur for many reasons, including missed meals, taking too much insulin, or exercising more than usual. At the same time, some individuals experience large swings in glucose more frequently than others, which makes diabetes management highly individual.
Tracking TIR helps identify patterns of highs and lows and allows you to make adjustments with your healthcare provider to improve control and quality of life. It is advantageous during times of rapid glucose changes—for example, when:
- You are sick with a cold, flu, or stomach infection
- You are going through hormonal changes, such as during menstruation
- You are pregnant
Using TIR data helps create a more personalized and responsive diabetes management plan.
What Counts as a Good Time in Range?
Target ranges can vary from person to person. However, general recommendations suggest that:
- People with diabetes aim for at least 70% of readings within range, meaning glucose is not too high or too low for roughly 17 out of 24 hours each day.
- For most individuals, the target range is 70 mg/dL to 180 mg/dL.
Those using injected insulin, individuals with gestational diabetes, or people with other health conditions may have different targets. Always consult your healthcare provider to determine the most appropriate TIR goals for your situation.
Is Time in Range Better Than A1C?
TIR is a practical and real-time measure of glucose control for both type 1 and type 2 diabetes. For decades, Hemoglobin A1C has been the gold standard for assessing long-term glucose management, providing an average blood sugar level over the previous 90 to 120 days.
While A1C remains valuable, it has limitations. A1C:
- Shows long-term averages but does not reflect daily highs and lows
- Does not indicate how often glucose may have fallen dangerously low
- Cannot show how lifestyle factors—such as meals, stress, exercise, or illness—affect glucose in real time
TIR fills this gap by tracking day-to-day fluctuations, making it a powerful tool for fine-tuning diabetes management. Ideally, both A1C and TIR should be used together for the most complete picture of glucose control.
How to Improve Your Time in Range
Life can make it challenging to stay within your glucose targets, but a few strategies can help improve TIR:
- Prioritize sleep.
Many adults only get 4–5 hours of sleep, but aiming for at least 7 hours can support better glucose control, insulin function, mood, and overall health. - Stay active.
Even a daily walk can help bring glucose into range. Physical activity boosts circulation and improves insulin sensitivity. If you’re prone to hypoglycemia during exercise, keep glucose tablets or quick carbohydrates on hand. - Consider intermittent fasting.
Fasting protocols may improve blood sugar control and metabolic markers. Many people with metabolic syndrome benefit from improved insulin resistance when using structured fasting plans. - Be aware of external triggers.
Factors such as alcohol, temperature changes, high altitude, or even sunburn can influence glucose levels. Understanding how these affect your body can help you plan and stay more stable.
Time in Range is a practical and insightful tool that empowers people with diabetes to understand their glucose patterns in real time and make more informed decisions about their daily management.