140 is an important number to be under?

I was reading a post that stated that if you spend even a few hours over 140 that damage is being done. I had not heard this before. Is this generally thought to be true? My son is Type 1. Does that make a difference?

Many of us use that number because studies have shown that significant time spent above 140 is when damage can start to accumulate. But, especially for a Type 1, it's inevitable that we go high at times. The key is to do what you can to stay under 140 (though some people aim for under 120) as much of the time as possible, and to promptly correct when you are high to reduce the amount of time you spend there.

Thank you so much!

I've seen this in blog posts, but I went to a Type 1 conference a few years ago where a researcher stated that 180 is the cut-off number for when noticeable damage to cells occurs. This is also about the number at which your body will try to eliminate glucose through the urine, so this makes sense to me. If 140 caused "instant" damage, then non-diabetics would never go over 140, but they often do, at least briefly. Non-diabetics never (to my understanding) go over 180.

So I'm not sure what to think, but ultimately aiming for a target that you struggle to meet isn't going to do any good. So I'd pick a target that's achievable and aim for that, and then lower it if necessary. As a Type 1, no matter which target is picked there will be times when it's not met.

From Wikipedia: The kidney filters the blood by collecting a filtrate. This filtrate contains waste products. In the first part of the renal tubule, the proximal tubule, glucose is reabsorbed from the filtrate. The proximal tubule can only reabsorb a limited amount of glucose. When the blood glucose level exceeds about 160 – 180 mg/dl, the proximal tubule becomes overwhelmed and begins to excrete glucose in the urine.

In healthy people the excretion process will never happen because their glucose level will always stay below the threshold of the proximal tubule. The kidney tissue responsible for filtering is stressed in any case by too much excessive glucose whether above or below 160mg/dl. Normally the tissue will just filter some glucose back to prevent the loss of valuable energy. If time is spent significantly above 160mg/dl then the kidney has to work much harder to achieve this.

I didn't mean to suggest it causes "instant" damage to go over 140, Jen, but just that studies have shown that is the level at which damage starts to accumulate. I believe the DCCT was one of the studies that stated this, though I'm sure someone else can come up with better references than me.

I agree with you that whatever target you pick, aiming to reach it more often than not, rather than "always' is a way to not set yourself up. Some people can maintain "between 85 and 100 all the time" but many (most) of us can't, or can't do so without dramatic efforts that impact quality of life.

I do actually disagree with you Jen about setting goals you may not meet. I think it's important to set good goals, not to settle for (and expect) high numbers. But yes, of course, to not beat up on yourself if those goals are not always met. I'm over 140 on a regular basis, but I correct promptly and go on. Or if it's a pattern I look to tweak things. I also think it's important to remember that "goal" and "target" for pump corrections are two different things. My "goal" is to be under 140 all the time. My pump target is 110. John Walsh explains the difference in more clear terms.

Sorry, the instant damage thing I was referring to some blog posts I've read (not on this site), not to your comment!

By goals I was referring to goals as you state them, not to pump targets (I don't even really consider pump targets to be goals, just settings that control what the pump does). But I guess when I was referring to not setting goals you can't meet, I meant more in the sense of don't set a goal just because *someone else* can meet that goal, and then beat yourself up if you can't do it. This is, of course, assuming someone is putting in full effort. It doesn't even make sense to call 140 or 180 a goal if someone is not even trying.

Part of the reason I mention the goal thing is that for the average person (not the majority on this site), even 140 can be a tough goal to meet. My *average* blood sugar is above 140 (indicated by both my meter average and A1c), and so if I set this as a "goal" it makes me feel like I'm failing all the time. So, instead my "goal" is to stay out of the double digits (below 180) as much as possible, because that is usually (not always) achievable. I still correct anything that is above my target range (which is 65-140), but to me target range is also different from a goal. To me a goal is attached to effort and achievement, while target ranges and pump targets are just numbers that we (or the pump) use to decide what actions to take. Looking at the OP's information, her son's A1c is 8.8. So suddenly trying to achieve "below 140" as much as possible may not be a realistic short-term goal.

So I think in this instance we are thinking of "goal" in different ways, you as a blood sugar target and I as some long-term thing to work towards.

Interesting points and thoughts Jen.

Obviously we all would like to have our numbers down low and under a1c 6.0;
yet as you point out may not be achievable nor desirable for safety based on what one's unique situation is.

My direct experience as a 30 year type 2 who had ended up with numbers in the stratosphere; once I got my numbers down to a1c of 6.9 - 155 and lower as an average; the hemorages on my retina's cleaned up and hve been clear for last 4 years and my health and kidneys have improved dramatically.

This tells me that it is very desirable to get my numbers down to 140 or lower if I can. a1c = 6.4

Interestingly from my doctor and other comments I have seen is that in hospitals, the reading I get is they get less deaths and folks heal better at 140 or a little higher and that more deaths and problems occur trying to hold a sick or older person to the numbers seen on a healthy non diabetic young person.

I do actually disagree with you Jen about setting goals you may not meet. I think it's important to set good goals, not to settle for (and expect) high numbers.
What works for a lot of people is to set routine goals, and "stretch" goals. That's my approach.

My routine goal is to exceedingly rarely go over 200, and be "most of the time" below 110.

Stretch goals are 140 and 90.

I meet my routine goals almost all the time. I'm getting better and better on the stretch goals, probably meeting them about 70% of the time.

I'm really excited about the day I can declare my stretch goals my new routine, and set some new ones (or maye, probably not!)

Interesting discussion, guys; I can see all sides!

My impression is that we just don't know, and CDC/ADA really should be studying the lower carb/flatliner types to see how they do over the long haul. Is there benefit to a 5.0 A1C for someone who isn't having lows and risking their life in comparison to a 5.5 or 6?

that 140 number has been thrown around a lot on this site. however, no medical professional, endo, CDE or anyone else has suggested or confirmed to me that damage starts at 140. However, my endo did say my goal should be 140 2 hours ppl. I don't think I've had a day where I didn't go to 140 at least once, I have a CGM so I can see my numbers 24/7/365. Not sure how old your child is, they too have different goals.

The 140 mg/dl threshold for organ damage is supported by extensive empirical data. Here is one example from among dozens:

Increased Prevalence of Impaired Glucose Tolerance in Patients With...

The way I look at it, the DCCT showed a REDUCTION of risk, but did not show elimination of risk at A1C of 7. So those diagnosed with T1 at an early age (eg will live more years with T1D) , and/or already have some complications, makes sense to me that striving for an A1C as low as possible will reduce the risk further, even without 'proof'.

Of course, only to the point where lows are not risking lives/quality of life, etc. There are many factors involved in determining what is the best/achievable A1C goal/BG ranges for each person, and it will likely vary in different phases of their life.

ADA DCCT 18 years later link

The original DCCT, which involved 1441 patients with type 1 diabetes, demonstrated that intensive glycemic control -- resulting in a mean HbA1c of about 7% -- reduced the risk for retinopathy, nephropathy, and neuropathy by 76%, 50% and 60%, respectively, compared with the conventional-treatment group, whose HbA1c averaged about 9%.

Targets link

Data from a new study suggests that currently recommended fasting blood glucose targets are generally lower than needed to achieve the target A1c values and some post-prandial targets may be too high.

All of the "140 mg/dl" studies that I have seen have been on people with Type 2 diabetes, not Type 1 diabetes. Jenny Ruehl (Bloodsugar 101) is a huge proponent of the magic 140 number, but every single study she references is on people with Type 2 diabetes, and Jenny herself does not have Type 1. Most people with Type 1 will have excursions over 140 mg/dl, and my personal opinion is you can stress a lot about numbers, but all that stress is bad for you. Many of the Type 1s who achieve lower A1c's do so by having lots of hypos, which is not a good practice and potentially extremely dangerous. Just my two cents.

I try not to go above 140 but there are times I do, it often happens as my basal runs out or sometimes for no reason, sometimes from meal spikes or reasons undetermined. When I do spike now I don't always correct immediately because I can come crashing down very fast and end up in trouble and sometimes it just comes down by itself if I'm active, it varies a lot. But overall I don't want to go hypo from a correction and I think it is better to not come down too fast as rapid fluctuations aren't good for us.

How old is your son?

Not sure I understand the logic here. When attempting to determine the level of blood sugar at which tissue damage begins to occur, why should the type of diabetes matter? If, say, an artery is being exposed to a potentially toxic concentration of glucose -- or anything else, for that matter -- does the artery know or care whether what type of body it's housed in? The study mentioned above found evidence of neuropathy in people who weren't identified as having any type of diabetes at all.

Not trying to be argumentative, just wish to understand the reasoning.

Footnote: Jenny Ruhl also makes the point that it's not the simple fact of exceeding 140 mg/dl, but also, and critically, the amount of time spent at that level.

Regarding complications, Type 1s tend to get microvascular complications whereas Type 2s tend to get macrovascular complications. Both due to high blood sugar, but the damage is different in the different diseases. Maybe someone else knows why--I don't--but it would be interesting to know. Also an important point here is that the OP is asking about her T1 son--we don't know his age, and if he is a child, I think it's important to realize that the "rules" are different for children.

True that -- children have a different rulebook.