Time in range standard is not set in stone

Continuing the discussion from Need feedback:

I read @Helmut’s comment last night and woke up this morning thinking about it. I’ve observed that the medical consensus regarding time in range has decided to use the 70-180 mg/dL (3.9-10.0 mmol/L) as a standard. I realize that they likely just want to create a landmark that they can use for comparison within the population of people with diabetes.

A dark side of that choice is that many patients will view that range as “normal and successful” for someone with diabetes. I, for one, have decided that while they can utilize that range for their academic, clinical, and research purposes, but I created and live by my own comparison range for metabolic success.

To begin with, I don’t start to observe physical symptoms of hypoglycemia until I hit 65 mg/dL (3.6 mmol/L). I spend a fair amount of time in the 65-69 mg/dL bracket and question, why should I concede this metabolically normal for me statistical turf? My performance as measured by my Dexcom CGM provides important feedback to me and helps sustain my motivation.

The higher limit that they set at 180 mg/dL or 10.0 mmol/L is unambitious, uninspiring, and tepid for me. I currently use 140 mg/dL or 7.8 mmol/L. I’ve also used 120 mg/dL for a time but decided that even gluco-normals do spend some time in the 120-140 mg/dL (6.7-7.8 mmol/L) range.

The important point, I realized, is that they don’t spend much time in that range. Their healthy pancreas pulls down their post-meal sugars back below 120 in relatively short order. I use my average glucose level to help monitor this reality. I shoot for under 100 mg/dL (5.6). If I can keep it at that level, then I know that I don’t have much of the 120-140 component in play.

Neither mine, nor your blood sugar metrics, @Helmut, represent well the diabetic cohort, unfortunately. So, I think that the 70-180 standard, while uninspiring to us, does help a considerable portion of our brethren. I know because I lived with A1c’s up into the low 8’s for a time. An A1c of 8.0% represents an average blood glucsose of 183 mg/dL (10.2).

For someone who uses the 70-180 range to motivate them to pull down excessive hyperglycemia into a better range, then I think that is useful. I think that reaching for better, in every human endeavor, is a helpful guide.

For those who find it easy to to fit their glucose statistics into the 70-180 range, I encourage them to lower the upper level down to 160 and then 140 to challenge them to reach healthier glucose metabolism.

I’ve read recently that only 12% of the American population can be considered metabolically healthy. That amazes me. But I see the level of obesity and the poor nutritional choices people make and tend to believe that alarming statistic. The demonization of dietary fat, especially saturated fat, has not served us well. Processed foods, especially grains, have contributed to our ill health. The low fat craze that started around 1980 also show the start of obesity and type 2 diabetes in this wildly unsuccessful population level experiment.

Our species can trace its roots back to about two million years ago. Evolution is a relatively slow process, especially when measured by our short lifetimes. Humans began cultivating grains about 10,000 years ago, only 1/2 of 1% of our two million year evolutionary track.

I think it’s one of the reasons we modern humans have suffered metabolically. It has made even worse impacts on our health when we figured out how to mass produce highly processed and highly palatable foods to consume. That combined with the public health decision to try to separate us from fats (meats), a nutrient that coincided with the rapid (evolutionarily rapid, that is) increase in brain size was a poor choice from my perspective.

In summary, I think that the 70-180 time in range (TIR) standard adopted by academics, clinicians, and researchers will help most of our group but individuals should be encouraged to tighten those limits to a healthier range when possible. Reaching for better is always better!


I concentrate on trying to achieve an average blood sugar of <110 and standard deviation of less <20. If I come close to those number my time in range (70-180) will be close to 100%. I view time in range as a by product of these two metrics. For well controlled diabetics 70-180 is uninspiring but for individuals that are trying to improve poor control it may be a decent metric but I would simply try to lower both average blood glucose and standard deviation.


@rcarli — Have you considered lowering your upper range limit number to get a more illuminating TIR statistic? Your standard deviation goal suggests great control.

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I’ve found TIR to be a great tool for me, not just while I was working my way down but also when the situation calls for something different. For instance, I just took my first overnight business trip since starting insulin so I adjusted my target range up a little - not because I knew I’d run higher, but because I WANTED to run a little higher. The temporary range helped me enforce my own guardrails.


@Jules — My TIR influences my thinking, too. Good for you for recognizing how our glucose goals need to flex with our dynamic lives!


I use a split range, which I do not hear much about in this forum. My split range was actually a recommendation from Dexcom. 6 AM to 10 PM range is 55 to 150 and 10 PM to 6 AM is 55 to 130. I can maintain 100% TIR and 17-18 std deviation for 30 days at a time when I work at it (Basically have no life beyond diabetes) Or when I travel, eat with friends, entertain, go out etc. can then only maintain 97% TIR and std dev can go up to 23. Q4 is loaded with holidays, birthdays etc. so I am willing to take the trade off and enjoy life with friends and family around the world. Other times of the year keep strict control.

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Yes, my person time in range is 70-140. Almost every article and many people quote the “standard” TIR so I keep Clarity at standard for comparison. Now that I know I haven’t gone lower than 98% in any month for the past year I could lower it but as I said I concentrate on the other two metrics.


@CJ114 — I am aware of the split range option but I don’t find it personally necessary. I think the more typical use of that option is to relax or raise the lower and/or upper limits during the sleep time.

Your time in range is great. With your low standard deviation, that likely enables setting your low limit at 55. I’m thinking that makes your doctor nervous, however. They don’t seem to fully appreciate that a low SD means your blood sugar level changes gradually and you are not often surprised by a significant hypo.

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Made my doctor go off the rails until she downloaded my Clarity reports that are a lot more granular in the Dexcom professional (doctors) application than in what we get as patients. When she was seeing regularly 30 days TIR with not one hypo or one hyper out of range, her only comments were she can’t figure out how I flatline so consistently and wished that she had other patients that can come close to my numbers. So now she just says I should keep doing what I am doing as she knows I am not about to change anyways and then asks what I need prescribed and how much.


I agree that 70-180 is probably reasonable for many people considering how many diabetics are told by their doctors (and are struggling) to get their A1c below 7. My gut feel is the clinical recommendations for the 70-180 range goes along with the blanket recommendation of shooting for an a1c below 7 that many of us heard when first diagnosed.

I’ve found that my TIR is episodic. For example, I just took a long trip, drove 4300 miles, lots of unpredictable meals eaten behind the wheel and generally poor sleep quality, little exercise. Experience tells me that a long day driving is terrible for my BG control. I was happy whenever I was in a range of 70-180 for those weeks.

I monitor a rolling two-week TIR for that reason. When I am home and in my routine, no anomalies pop up etc. I use 70-150 as my range and often hit 80%. There is usually at least one anomaly during those two weeks, like a restaurant meal, an unpredictable pint of micro brew, a day spent mostly driving, or a day spent sitting in a meeting, etc. Breaking that TIR tracking down to two weeks helps me isolate those anomalies and figure out how to approach them next time.


Good post @Terry4. This is what I was driving at when I suggested @mohe0001 focus on TiR and then tighten it up.

FWIW, I think that while I’m not one to promote participation awards, it IS helpful to set small achievable goals and work from there.

Put another way, the journey of a thousand miles begins with the first step.


These of course can all be micro managed with a CGM, however, when these life happens events are thrown at us we often ignore them with good reason as it is more important to be in full presence of the anomaly and totally enjoy that meal, pint of brew, drive, meeting, family, friends etc. and put diabetes management on hold for a moment. We all need a break from time to time and just have to make sure these breaks are the rare exception rather than becoming habit.


I definitely regret my not so nice comment that sparked this thread. Thanks @Terry4 for turning it into something positive.


@Helmut, your comment did not bother me at all! Don’t worry about it. I think we all have some strong notions about our health and diabetes. Your comment was thought provoking to me and I’m sure for others. And I certainly agree that for those of us who can do it, we should keep our blood glucose as close to normal as possible.

I always enjoy reading your comments. Keep them coming!

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I was wondering why TIR stirred up my emotions and causes me to lash out. I am angry at the many doctors that told me that my control was excellent and I should keep doing what I was doing. I met today’s standards and still ended up with complications after only 25 years. During these years my happiness was closely linked to the color of urine test strips. My insurance paid for 100 strips per month but since they were so cheap I bought enough to test 100% of the time. I also started consuming a lot of fluid and peeing frequently so that the test results were less outdated. My assumption was that I had stayed below 180 if the urine test strip didn’t change color. Fast forward to today. ADA recommends to stay below 180 at least 70% of the time. 30% is 7 hours per day. Releasing sugar into my urine for 7 hours per day, every day, sounds so wrong.


I get panicked around 80 and 150. Not because there there is a big deal beyond that, but because I know if I get there I am certainly going below, 70 or higher than 180.

The difference being when I am thinking of exercising then 150 and above is fine. After 45 years my BS is so brittle that it can race up and down at nearly the speed of a kernel of popcorn in a pan of hot oil.

For those of us who use a CGM, time in range is a great statistic to follow. Whether the standard 70-180 range or something tighter is what motivates us, I think we should also pay close attention to standard deviation.

Standard Deviation (SD) is a measure of how close our data resides to the average or mean glucose for any period. The smaller the number, the closer the data is to the average. It is denominated in mg/dL or mmol/L.

If your data set does not diverge too far from the average then it greatly reduces the risk that a blood glucose level level near one of your boundaries will dive or skyrocket well beyond your limits. A low standard deviation increases your confidence to stand pat when you see a 71 mg/dL and your limit is 70.

For several years I aimed to keep my SD at 30 mg/dL (1.7 mmol/L) or less. That target helped me a lot. I now shoot for lower.

For me, I could not experience a SD at this level without my carb-limited way of eating. Prior to limiting carbs my SD was more typically at 45-60 mg/dL or more. That meant I had to aggressively “defend” any trend headed toward my lower limit. That meant adding emergency carbs and often lead to the glucose roller-coaster.

I realize that some here can eat more carbs and still manage well-behaved CGM traces but I’ve not been able to do that. Diabetes is often metabolic mayhem and we can often do the same thing day after day and see different results. Eating is probably the single biggest factor (I know there are many more!) that we actually control, so I choose to employ a way of eating that enhances my chance of enjoying good post-meal lines.

No food tastes better than a great blood sugar feels! The great blood sugar sensation lasts much longer and it’s emotionally satisfying, too.


The value of Time in range (TiR) is directly proportional to the understanding of the metric and the importance an individual places on their metabolic well being.

Those of us with T1D who have used CGM’s for a number of years are far more comfortable with the data than those who’ve only used CGM’s a short time or those people who’ve never worn one. My endocrinologist is a perfect example of someone who doesn’t know Bupkis about TiR, which is pathetic in this day and age. He becomes hyper when he see’s my non-diabetic A1C’s, and despite the data believes I must being having dangerous hypos.

As someone who’s lived with T1D for nearly 6 decades, excellent BG control is mission critical for me. I’m dealing with some diabetic complications that never crossed my mind 20 years ago, a time when I still felt I was impervious to complications.

I’d always had “good” BG control, even 25-30 years ago (A1C’s in the 6-7 range). I realize now those numbers - which were applauded by my doctors of the day - were nowhere near low enough to stave off complications.

For my own well-being, running numbers anywhere > 5.0 mmol/L (90 mg/dl) makes me uncomfortable. I aim to keep my average BG < 5.0 mmol/L (90 mg/dl) with an A1C somewhere between 4.6-5.0.

I typically run ranges far lower than most people here, primarily because being in ketosis, I suffer no loss of cognitive function until I reach 2.5-2.7 mmol/L (45-49mg/dl). My brain is fuelled by ketones.

On the high side, I cringe whenever my BG goes > 7.0mmol/L (126mg/dl), and I have high alert set at 8.0 mmol/L.

I generally run 97-98% TiR with these thresholds, because like all of us life sometimes gets in the way. I reset my G5 this morning, and as so often happens I saw false lows within an hour. Those of you who still use the G5 can relate to this phenomenon.

Typically I’ll have 3 or 4 100% TiR days a week, the others will have lows that I’m not uncomfortable with however the software doesn’t allow me to set lower thresholds that are in line with my comfort zones.

Using 3.1 & 7.9 mmol/L (56-142 mg/dl), my TiR=96%, SD=1.1 (20 mg/dl), Avg BG=4.9 (88) and est A1C=4.7


@Jimi63, the rationale you cite for maintaining tight management of your BGs makes perfect sense to me. I share your values but am not able to get my average BG quite as low as yours. My SD is close to what you report.

Like you, I’m able to achieve these kind of numbers due to maintaining my metabolism in nutritional ketosis. I also fast like you but not often beyond 24 hours. I did, however, fast for 42 hours recently and enjoyed some outstanding glucose levels.

My day after the fast ended results reminded me that fasting’s effect on BGs persists after the fast. On that day I experienced 100% TIR (65-140) with an average BG of 97 mg/dL and a standard deviation of 13 mg/dL. That was three days ago and the number of times I needed to correct a high glucose level has gone down from 3-4/day to almost zero.

For anyone who wants to settle down BG chaos, fasting is a potent technique.


I just started intermittent fasting at the beginning of October (up to 18-20 hours per day) - my blood sugars have been AWESOME, in range almost every day. I’ve had a tricky time this week, likely due to other hormonal fluctuations (ugh) but otherwise it’s been great. I have lost weight and had lots of energy. The last couple of days I have done OMAD (one meal a day), which I’m hoping makes the weight loss continue, and keeps my BGs in a great range.