What does 'Time in Range (TIR)' mean to you who have diabetes? Let's explain it simply!

As a person with diabetes, how much do you think about your blood sugar levels throughout the day? How are they in the morning, how are they after lunch, how are they before bed, and so on. One of the things you hear a lot when talking to your doctor is the term 'A1C'. It's often used to determine whether your diabetes is under control. But is A1C the whole story? Today we're going to talk about a new and much more useful method that will give you a deeper understanding of your diabetes than A1C. We call it 'Time in Range' or 'TIR'.

What is Time in Range (TIR)?

Simply put, Time in Range (TIR) ​​is the amount of time during the day that your blood sugar levels remain within your "target range." This is usually measured as a percentage.

Now you may be wondering what this "target range" is. For most adults with Type 1 or Type 2 diabetes, but not all, this target range is a blood glucose level between 70 mg/dL and 180 mg/dL .

Doctors generally recommend keeping your TIR above 70% . This simply means that your sugar levels should be within that range for at least 17 hours out of 24 hours a day.

How do we measure this TIR?

The best and easiest way to accurately measure your TIR is to use a device called a Continuous Glucose Monitor (CGM) . This is a small device that you wear on your body. It measures and records the glucose levels in the interstitial fluid under your skin 24 hours a day. You can then download that data to an app or software to see exactly what your TIR is.

Actually, the usual method of taking blood from a finger can also give some idea of ​​​​the TIR. But for that you have to check your sugar several times a day. However, the amount of data obtained from a CGM is much more than that. Therefore, the TIR value obtained is also very accurate.

With this CGM technology, many people with diabetes and their doctors now look at this TIR value to assess how well their diabetes management is working. With this data, you and your doctor can set new goals and make necessary changes to your treatment plan.

How do I view a Time in Range report?

If you use a CGM, the TIR report usually shows you a colored vertical bar. This is easy to understand. Green indicates when your blood sugar levels were in-range. Other colors (yellow, orange, red) indicate when your blood sugar levels were out of range (low or high).

Let's look at how a typical CGM report displays information.

Your CGM report may display this information differently. If you have any questions about this, ask your doctor for clarification.

How long should my Time in Range be?

You and your doctor will decide together what goals are best for you. Also, these goals do not stay the same throughout your life and may change over time.

Factors like these come into play when determining your goals:

• How long have you had diabetes?
• Your age and life expectancy.
• Do you have other medical conditions that affect your blood sugar levels? (e.g., kidney dysfunction, gastroparesis)
• Do you have cardiovascular disease?
• Do you have hypoglycemia unawareness, a condition where you don't feel the symptoms of low blood sugar (hypo)?
• Are you pregnant or hoping to become pregnant?

Okay, so let's look at some commonly accepted TIR goals. Again, these are just general recommendations. Your goal may be different than this.

Goals for gestational diabetes and type 2 diabetes during pregnancy may be different, so it's important to discuss with your doctor what goals are most helpful and realistic for you.

What is the relationship between A1C and TIR?

It is very important to understand the difference between these two.

• TIR (Time in Range) is a measurement that provides information about the fluctuations in your sugar levels over a period of hours or days.
• A1C is a blood test that shows your average blood sugar level over the past 2-3 months .

Think of A1C as reading a summary of a chapter in a book. It gives you a little idea. But TIR is like reading the entire chapter, every word, every sentence. You get every detail clearly. An A1C doesn't give you any information about how high or low your sugar is.

Why can an A1C be misleading?

Think about these two people.

1. First person: His blood sugar levels fluctuate throughout the day. Sometimes they are very low (hypo), sometimes they are very high.

2. Second person: His blood sugar level remains fairly stable throughout the day, around 154 mg/dL.

Both of these people may have an A1C of 7%. Because A1C is just average. However, their TIR values ​​are completely different. The first person's TIR is much lower. That means their body is at higher risk of developing the side effects of diabetes.

Also, people with the following conditions may have inaccurate A1C values:

• Anemia
• Hemoglobin variants
• Iron deficiency
• Pregnancy
• Liver disease

For now, TIR won't completely replace the A1C test. Decades of research have shown that A1C levels can predict your risk of developing diabetes complications. That's why doctors use both A1C and TIR together to get a more complete and accurate picture of your diabetes management.

Why is Time in Range (TIR) ​​important?

TIR gives you a much clearer picture of the fluctuations in blood sugar levels that come with diabetes. Things like the food we eat, the exercise we do, the medications we take, and our stress levels all affect blood sugar levels. When you look at your TIR data, you can understand how each of these things directly affects your blood sugar levels.

For example, imagine that you had a fever for a week. When you look at your TIR report that week, you see that your TIR value has dropped significantly. Then, the next time you get sick, you can talk to your doctor about how to prepare for it and manage your diabetes in advance.

TIR and diabetic complications

Research has shown that there is a link between low TIR values ​​and complications caused by diabetes.

Glycemic variability can increase oxidative stress and inflammation in the body, which can damage cells in the body. Research has found that this high variability in blood sugar levels increases the risk of:

• Increased incidence of hypoglycemia.
• Increased risk of cardiovascular disease.
• Impairment of mental and intellectual functioning (cognitive function).
• Declining quality of life.

Furthermore, one study found that Type 2 diabetics with low TIR and high blood sugar variability were more likely to have severe cases of diabetes-related retinopathy. Another study found a strong association between low TIR and cardiovascular autonomic neuropathy.

All of this shows how important it is to keep your TIR value at the maximum level.

How can I improve my Time in Range?

The main way to improve your TIR is to identify exactly what factors are affecting your sugar levels. This can take some time. It can really feel like an endless scientific experiment.

Imagine that you notice that your blood sugar levels only go out of range after breakfast every day. So, pay attention to your habits and activities at that time.

For example, things like these can cause blood sugar to spike after breakfast:

• It's time to take your diabetes medication (like insulin).
• The dose of the medicine.
• The balance of the foods you eat and the nutrients they contain (carbohydrates, fats, proteins).
• Other medications to take in the morning.
• Drinking something that contains caffeine, like coffee, in the morning.

This is just one example. Diabetes is a very complex condition. There are many ways to help improve your TIR. Always remember, before making any changes to your treatment plan, talk to someone who specializes in diabetes, such as an endocrinologist or a certified diabetes care and education specialist (CDCES), or at least your regular doctor.

Time in Range (TIR) ​​is a new and very useful metric for measuring diabetes management. At first, it may seem a little difficult to understand all this TIR information and data. But don’t worry. Your doctor will explain it all and help you use this TIR value to your advantage. Together, you can track how your TIR changes over time and adjust your management plan accordingly.