Low Blood Glucose Doesn’t Affect Long-Term Brain Function

A study published in the May 3 issue of The New England Journal of Medicine shows that episodes of severe hypoglycemia (very low blood glucose) do not seem to have any lasting effects on cognitive function in teenagers and adults with Type 1 diabetes.


The study, which was led by researchers at the Joslin Diabetes Center and conducted through 28 additional medical centers around the United States, involved 1,144 people with Type 1 diabetes. These people had all been participants in the Diabetes Control and Complications Trial (DCCT), a landmark study that began in the 1980’s and proved that intensive, or “tight,” blood glucose control lowers a person’s risk of developing diabetes complications, such as retinopathy (eye disease), nephropathy (kidney disease), and neuropathy (nerve disease). The DCCT participants in the intensive therapy group achieved HbA1c levels (a measure of blood glucose control over time) nearly 2 percentage points lower than those in the conventional therapy group and developed fewer complications. However, they were also three times as likely to experience episodes of severe hypoglycemia, which can lead to coma or seizure.

Because severe hypoglycemia can cause nerve cell death, experts wondered whether severe hypoglycemic events might have any long-term effects on people’s cognitive function. To answer this question, researchers tested the cognitive abilities of DCCT participants from both the intensive and conventional therapy groups at the beginning of the DCCT and an average of 18 years later. They also recorded incidences of hypoglycemic coma or seizure in the participants over that period of time.

After adjusting for age, sex, education, length of follow-up, and number of cognitive tests taken through the years, the researchers found that episodes of severe hypoglycemia did not have any effect on participants’ cognitive abilities. They did find, however, that people who had higher blood glucose levels (or HbA1c levels above 8.8%) experienced some decline in two measures of cognitive ability.

These results show that consistently higher blood glucose levels appear to be more of a threat to long-term brain function than occasional episodes of severe hypoglycemia. However, it is important to remember that hypoglycemia, when not recognized in time, can result in serious injury and even death, which is why it is important for people who use insulin or a diabetes drug that can cause hypoglycemia to monitor their blood glucose levels regularly. This is especially true in people who have developed hypoglycemia unawareness, a condition in which they do not experience early warning signs of hypoglycemia (such as shakiness, dizziness, or sweating).

Also, the effects of severe hypoglycemia on the developing brains of children are still unclear, since the youngest participants in the DCCT were 13 years old at the time the trial started. Further study of hypoglycemia and cognitive function over time in people younger than 13 is needed.

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  • yanalith fortul

    su pagina me parece muy buena, pero,me gustaria obtener mas informacion acerca de como actua la glucosa en el cerebro, ya que estoy elaboranda un trabajo acerca del tama.

  • Amanda

    Low blood sugars don’t USUALLY affect brain function. Usually instances of low blood sugar are not severe enough to damage the brain in a manner that will be outwardly visible in cognitive loss. However, if they are severe enough, prolonged enough, and occur over enough time, they absolutely will cause enough brain cell death which will result in short-term memory loss as well as issues with cognition.

    Diabetics who are Type 1 Hypoglycemic Unaware (who cannot tell when they’re blood sugar is dropping and therefore cannot do anything about it) often develop cognitive loss that is very similar to early-onset dementia. This is because these people usually have abnormally low blood sugars for prolonged periods of time- longer periods of time than someone who can feel the physical symptoms of low blood sugar. Any type of seizure or loss of consciouness, regardless of it’s cause, will result in brain cell death. When this happens on a regular basis, for many years, and for long periods of time- the result is a slow loss of cognition.

    My father has been Type 1 Diabetic for 40 years (since he was 20) and is also hypoglycemic unaware. He has developed what most closely resembles severe dementia that has been slowly getting worse for about 10 years (since he was 50- too early for any normal dementia of this severe nature). His doctors cannot find any other cause other than multiple attacks on his brain due to severe low blood sugars. A study that tests only a span of 18 years, is not nearly long enough to study long term affects when you consider that many of these people will have been diabetics for 50 plus years.

    It is true that most type 1 diabetics, like the ones in the above study, will never experience outward symptoms of brain damage or cognitive loss as a result of their low blood sugars, but that is because their brains can cope with the minimal trauma it receives. Low blood sugar does cause brain damage and cell death which can result in loss of cognition and memory loss when severe enough. Just because it is not outwardly visible, does not mean it is not occuring. It’s simply that the instances of low blood sugar are not frequent or prolonged enough to appear in outward symptoms of brain cell death.

  • div

    My father is 54 years old. He has had Tyoe 2 Diabetes since he was 19 years old, so for about 30 years. He is Hypoglycemic Unaware, suffers nerve damage and has been having mild to severe low blood sugar “reactions” for well over 30 years. I would say on average he has about 100 or more per year. He is definitely not the same father I was raised with. He has a hard time communicating and to me has a significant loss if cognition and brain function. The problem is that I don’t know how to get quantifiable evidence of this loss of brain function so that he may increase his disability with the VA, and receive some type of care in his daily life as he is an honorably discharged Veteran. Are there any tests his doctor can recommend be performed to test his brain function or even look at his brain to determine the damage he has incurred?

    Please help…

  • Jadeland

    I have nesidioblastosis (hyperinsulinemic hypoglycemia) resulting in many severe hypoglycemic episodes with seizures and eventually had 85% of my pancreas removed. I began to experience significant short term memory loss, concentration and focus problems. To answer your question div, my neurologist performed an EEG, MRI and memory and focus testing which confirmed significant and permanent damage of a metabolic nature. I used to love to read but now I can read a page over and over and still not remember what I read. I have even gotten lost while driving in very familiar areas. I have had to pull over in a panic because I couldn’t remember where I was going. I am afraid to drive anywhere alone. I cannot work anymore. I lose things constantly. I have developed motor tics in which my head and shoulders jerk. It is very embarrassing making me rarely leave home. This has all caused anxiety and depression. I still experience hypoglycemia although not as severe. My endocrinologist is concerned about further damage. My world has turned upside down and I know it will never be the same and will never improve.

  • N.R.S.

    I started getting very bad low blood sugar attacks starting this year. What made it worse was a dr started giving me testosterone! That made it even worse! It got so bad that I had to leave work for many weeks. I couldnt take care of my kid or drive or leave my apt. Dr’s wouldnt take me serious. Relatives thought I was just over reacting and being cooky. The strangest scarriest feelings would happen. Its like my memory was not in syn with the present. I could say a word but hear it a few seconds after. Since the memory is the brains way of giving you a conscious, giving you that individuality of self feeling, I suddenly felt like I was not real. Like I was a program in some computer. Id walk in my apt and suddenly feel like I was back at another home I had 12 years ago. Sometimes when driving I would forget where I was goin or where I was at. It got so bad that I just decided to tell my ex to take care of our child cause I was scared Id forget her somewhere. Miraculously and without any good reason my insulin went from 70 most of the time to about 12! The low blood sugar was gone in a matter of 6 hours during a 3 day test at the hospital. They would check my insulin and other things every 6 ours. Only thing I can attribute to that is 1 dose of Chromium the day before and 2 doses, 1 the day before and one the same day of L-cartinine. Since then i havent taken one dose and still have no low blood sugar. But I still have the odd memory problems. Im really scared I have perminantly messed something up in my head and now will never be normal. But its only a week since I stopped having the attacks so maybe in a month it will get better. I dont have the attacks like I did but the memory is just so messed up and I still get odd headaches and confusion. Most symptoms are still just like I have low blood sugar but without the low blood sugar being evident! If it continues I have no choice but to stay out of work nd live a very sad, miserable life. Will this last 2 weeks? 2 months or years? I have no idea if it will ever get better. Im more worried about my kid than anything. I cant just quit life and leave her without a father. But the way i am now, she has no fun with me. So Im in a bad situation. And then there are the bills! Thousand of dollars in bills and I do have insurance but its still rediculously expensive. If the Drs would have taken me more serious and tested me much faster I think id be a much healthier person right now. I had 3 Emergency room visits end with them saying they cant do anything cause my sugar is normal. So i leave. 2 hours later Im almost in a coma and cant make it back to the emergency room. Its insane the lack of care Dr’s offer. Sorry to be so down but this sickness is not something you can wait around to fix itself. Find someone fast that will help you quick.

  • kathy hindman

    Amen to this! as I have suffered from extreme
    lows for years , as a Type 1 diabetic for 28 years and my blood sugar was 38 mg/dl 10 mins ago and here I type….

  • Tere Wells

    My daughter is 11 years old and experienced hypoglycemia frequently in 4th grade. Since then her grades have declined and her ability to focus when taking tests has declined as well. You speak of the age levels for the testing being 13 and older…..Nevermind I see where you wrote that further testing in younger patients is needed. My concern was if the hypoglycemia can affect younger children.

  • Lauren

    I have had Type 1 diabetes for 33 years (since I was nine years old). In the past five years, my cognitive ability has declined in a variety of ways. My friends and family members consider me “scattered” as I have difficulty focusing, misplace things constantly and often forget what I was in the middle of saying. It did not happen overnight, it was gradual and continues to worsen. It is frustrating for others to be around me at times for they try to normalize it as being busy with children, chaotic schedules, trying to do too much, etc….

    However, I am an intelligent woman who has achieved significant academic success over the years. Something has changed. My husband just called as I was writing this blog and he responded “I forget things all the time!” Obviously, people who love us want this to NOT be ANOTHER complication of diabetes. But, for those of us who know who we are, how are minds work and what is “normal, ” we just know something is just not right.

    I offer these comments as support in case anyone else is feeling frustrated by their own absent mindedness. In the meantime, I will implement behavioral strategies to minimize the effect it seems to have on my daily life. Thanks everyone for their candor and honesty. Hang in there! The alternative sucks more than the cognitive impairment.

  • Bob Cockrell

    I am 74 years old and have been a type 1 diabetic since 1958 (53 years). I have never spent even 1 day as a patient in a hospital in my life. I have a Ph D in nuclear engineering. In retirement, I tutor HS students in advanced math, am webmaster for a Christian preschool, and I ballroom dance about 6 hours/week, frequently performing at retirement homes. My favorite method of exercise is high-energy deep-water aerobics. I have always tightly controlled my diabetes and now have hypoglycemic unawareness. Consequently, I must test frequently (typically 6 times/day and always before and after a sugar burning activity.) Since 1958, I have passed out about 10 times. Before home blood testing meters became available around 1980, I performed urine tests, using Clinitest tablets at home and testape away from home. The day I was diagnosed, I bought food scales that measured in grams and read the Joslin Diabetic Manual. I still weigh and measure food at home and I try to stay current about diabetes. I have never taken a day off from control, and am proud to say,”I feel wonderful.” I weigh 176 and am 6 feet tall. I have never asked, “Why me, Lord?” but I have frequently thanked God for bringing me safely this far. One final comment, my 75-year-old brother doesn’t have diabetes and could always eat anything. He had 5-bypass heart surgery when he was 70!

  • Fred

    I am oncerned that I am suffering short-term memory loss. I have suffered regular occurrences of hypoglycemia (2-3 times per week)since undergoing a gastro-oesophigeal resection five years ago due to cancer – I believe that this is a fairly common condition after gastric surgery. I generally detect the hypoglycemic “attacks” pretty quickly, and I and my family/friends know what to do when they occur, so they are usually short-lived. I am concerned, though, that my frequent headaches on awakening may result from undetected hypoglycemia whilst sleeping. The memory loss has been more recent (past few months).

  • Friend of Ted

    My husband’s friend is living with us short term – until he finds a job. My concern is that he has become Hypoglycemic Unaware but he does not want to admit this. He had an episode last night that he doesn’t remember and claims that all that happened last night was he was asleep and fell out of bed. He has no answer to why he then went into another bedroom to sleep and couldn’t even tell me his name for two hours. He has chipped teeth from falling, he has had black eyes, bloody nose… He has had about 5 major car wrecks in the last 5 years, luckily only one person had minor injuries, and about 10 or more (that I know of) minor car wrecks. He has a law degree and is intelligent but now when he talks he sounds drunk. While he is a very nice guy he has been very lazy and is not worked in about 22 years and he has finally ran out of money. After reading about Hypoglycemic Unawareness I know he has a major problem but how do I get him to see this? He told me last night that this is not due to his diabetis – everyone has these episodes where their blood sugar drops. He stopped testing himself several years ago and is very upset with me in that I demanded that he test himself at least once a day while living with us. What do I do now? What does he do now? And to make matters worse he worked for the government and they had a special IRA instead of social secruity – so now he has no SS benefits. He is 59 year old. What CAN he do now? He thinks he can land a $40 to $75 thousand dollar a year job – but not if he is having Hypoglycemic Unawareness about 5 times or more a month and sounds like a drunk! Any suggestions would be helpful!

  • D.C.

    Bob Cockrell, you are my hero! What a fantastic and inspiring story your life is. Thanks for sharing it!

  • Deb

    I was diagnosed w Type 1 in 1973, and doing decently now. Bob Cockrell has an Incredible story! I’ve never heard of anyone who was so strict with their glucose control! Good Job. I grew up being terrified by stories of people who weren’t careful to take care of their conditions.(Not because my parents were being irresponsible, just making sure I knew why I needed to be careful what I did.) I was determined I wouldn’t be one of those who had bad kidneys, blindness, heart problems, loss of nerve function, all the things that can start making a normal person’s life miserable. In my 20s, I was a Christian, wanting to be a supportive wife to the guy I loved, in great health, just married, “of course I’m fine, nothing you need to worry about” not wanting my husband to think I couldn’t take care of my condition. Dumb! If he loves me, of course he wants to help out. I’m still not in bad shape, but I’ve had lots of times when I went to bed, and the next thing I remember is Deb! Drink some now, you need to drink some of this! My husband holding fruit juice to my mouth because I woke him up when I started shaking/sweating in my sleep. He’s been a staunch support through the years, but he’s had to support me a lot of times when I could have avoided the problem by being more diligent on the control routine. I definitely have the Unawareness. I’ll decide I’m sleepy when I shouldn’t be, check my blood sugar, and here I am, 28! Scary. A lot of the lack has been the cost of supplies. We lost our health insurance about 10 years ago, and I hoarded the glucose test strips I had for when we were on vacation, or away from home for extended periods. I don’t know of a way to have it tested, but I do think I may be starting to have issues with short-term memory & occasional speech impairment. I’ve read that normal Type 1 diabetics look to spend about $800 monthly on supplies? I’m lucky to be able to spend $1,000 yearly. I’ve contacted places that advertised discounted diabetic supplies several times, and they always want to know what insurance I’ve got, and offer me a free glucose meter. The life-supporting medication I require is not available unless I have a current insurance policy. Lantus, Humalog, and probably some of the newer stuff worked really well for me when we still had health insurance to afford it, but I get by with the R & N humulin types that I used before I was 10 years old. I can echo what Mr. Cockrell said, God has blessed me. I don’t want to waste that by ignoring the health I can enjoy. My advice to anyone who reads this is to remember that no matter what, a close relationship with God is indispensable for anyone, no ifs! DON’T get discouraged and give up trying to have a healthy routine. The cumulative effects of high glucose are scary. I’ve got three beautiful, healthy daughters that were born after pregnancies with no complications, and after salvation itself,there isn’t anything I can think of that should be a better incentive to be grateful to my Lord for everything I’ve been given.

  • tamiw

    Has anyone had a severe insulin reaction that lasted an extended period of time where the symptoms didn’t go away once your blood sugars stabilized? If so, how long did it take for them to finally go away?

    • Xiggy

      Hi tamiw – I know I’m answering 5 years late but I wanted to say in case others want an answer to this question :)… I have had severe insulin several times. I had a low-sugar-induced siezure once while asleep (resuscitated by ambulance crew), and getting over the feeling of dizziness, terrible shakes, and feeling very very cold took maybe 5-6 hours; I don’t know if that was because of a physical reaction or simply due to the fear and disorientation of waking suddenly with an oxygen mask on with 5 strangers standing around my bed.

      I also have had waking severe low blood sugar epsiodes a few times (tested sugar and found below ~15mg/dl). In those cases I felt “ok” maybe 3 hours later, but still kind of ill and weird and just “not myself” about 12 hours later. I am guessing that is because of 1) the fact that in each case I over-reacted and consumed about 150-200g of glucose in one sitting (juice, soda, sugar stirred into milk) such that my body was on an extreme and shaky sugar high and 2) the body’s natural reaction to a severe low is that your liver does a superduper glucose dump, so that typically for maybe 3-10 hours after a severe low, your body is still supplying itself extra glucose. So I ended up with high blood sugars for a while thereafter.

  • Janet

    I highly recommend watching these YouTube interviews on successful treatment of cognitive loss with coconut oil. When the sugar doesn’t/can’t reach the brain the coconut or palm oil converts to ketones and does the job.

    I have no connection with selling coconut oil, but I am trying to find answers for my brother who became Type 1 diabetic in his early 30s. Perhaps he had it a lot longer before he was diagnosed and his wife seems to think a lack of sugar to his brain over a long time has caused some cognitive loss and lack of social skills and filters – almost like Ausperger’s Syndrome. If anyone has info that relates, please share. Thank you.


  • Sarah smith

    I was wondering what you think the chances are of a infant that may of suffered from hypoglocemia due to a medical condition suffering long term effects(brain damage)

  • Diabetic Chick

    Wow. I am glad to hear people talking about this. I have always felt that due to an earlier episode of severe low blood sugar that caused pyschosis; my brain has not been functioning well. After that i had difficulty focusing and understanding things that i read quickly. Glad to know that there are other diabetics that have experienced this.

  • Linda

    Thank you for this very helpful article on long term memory loss. I understand that when my reading are severly low (<50), that sugar is not getting to my brain, causing me to be slow to react or unable to communicate effectively. I was afraid that it would have long term effects on my brain. Thank you for giving me some peace of mind.

  • Susan Benton

    I have been Type 1 insulin dependent diabetic 45 yrs and ” brittle ” no matter how hard I try to maintain regular levels of my blood sugars. I test more often that most people have to, because lispro insulin just plunges my sugars down too fast.I have had tested 33 at 5 or 6 in the morning, only to go up at almost 400 later…I always feel absolutely awful after these episodes. I feel better when when I`m slightly high ( between 150-200 ) than at 120-80 …which would be great but those numbers keep dropping. My last A1c was 7.7 . I had a kidney transplant 8 1/2 yrs ago…but worried that this kidney might be getting damage because of my ” poor control ” .

  • Matt R

    I’m not entirely sure if I totally agree with this article, I have type 1 Diabetes, and i’ll say not one single study will tell you everything, since they seem to be more focused on long term effects and not the here and now aspect of it.. and when I experience Severe and I do mean severe, Low Blood sugars, and this usually happens when Sleeping I might wake up, but not Remember it later when I am normal, and as My mom can tell you, I can get Violent while laying down or if I am able, standing up, until as she tells me its too much for me and collapse…. and while all this happens, I don’t at all remember what the heck happen.. Im not to sure if its the Brains Survival instinct kicking in or what, is trying to kick in or not, but I can be Irrational as well at this time from what My mom tells me… and do things that really arent my intention at all… but at that moment these kind of Low Blood Sugars definitely do have an impact, and does affect Short Term memory…. at least for me it does…..

  • Marc W

    I’ve had type 1 diabetes for 21 years and well since I am only 23 you can pretty much say my entire life. Most diabetics can at least have a memory of when they were little and didn’t have to take injections etc. but anyway I believe all the management early on and responsibility put on me at such a young age help mold me into the great person I am today. I am doing quite well, my intelligence has helped me live a really good successful life so far but this is were the concern comes in.

    About 5 years ago I had DKA and had to be hospitalized for a week, pretty much after that doctors and family members drilled it into my head that high blood sugars were extremely bad and low sugars were not good but “better” than highs. At the time I could easily tell when my sugars were low and wake right up if I was sleeping. So naturally I pretty much brushed off low blood sugars as not such a big deal, I got my A1C down to about 6.4 and everything seemed fine. Until recently…

    I work overnights so my sleep pattern is somewhat strange but I fear I may have started to contract hypoglycemia unawareness because I no longer wake up when my sugar is dropping until it is dangerously low. This change started happening about a year ago and i’ve woken up in a trance like state a couple times, like being in a bad dream but one you can’t wake up from because it’s actually happening. Stuff floats, the floor usually isn’t there and things you can actually tell what they are, are 5x bigger or 5x smaller. Really eye-opening to when you see a chair and it looks like a toilet to you and well you can guess what happened next. That’s when I realized something was severely wrong and just screamed thank god my dad heard me and could get me food or else I could have ended up dieing because right now I can say yea the low sugar caused that but at the time I had no idea what was going on.

    I used to always be able to feel when my sugar was dropping but not anymore, to test it out the next time I “felt” like my blood sugar was low I tested myself and I was 48…well below 70 and also that was when I first felt slight discomfort but not enough to wake someone up which would explain why my sugars are so low when I finally do wake up. Also one thing I have noticed is when this happens it seems to always be worse than the last time. Making me believe my sugars are getting lower each time before I finally do wake up. Of course there can be a lot of factors other than this why I may not be waking up, but I don’t know how many more times this can happen before I just don’t wake up at all.

    I now realize that I can’t lean on feelings anymore and have to monitor my sugar more carefully and not brush off lows as nothing because they’ve given me a lot of problems as of late. I just really hope this study is correct about long term effects from many lows, I have relied on my intelligence for so long to get me where I am today. If my brain is damaged and doesn’t allow me to think properly I would be devastated. I have confidence I will figure out a way to control my low sugars but really hoping it isn’t too late and with proper diabetes management I can become somewhat hypoglycemia aware again.

  • Anne

    I’ve been diabetic since 24 and I’m 40 now. I’ve had good control on and off over the years. For the past 6 months I’ve been trying to keep tight control and as a result, I’ve had lots of scary lows. I guess I”ve become hypoglycemic unaware because I no longer sense lows until they’re really bad. I recently ended up in the emergency room after having blacked out in front of my kids and family, vomiting up the lovely dinner my mother had made for us…it took 3 shots of glucagon to bring me around, so I must have done something really stupid like switching insulins and dosages. Anyway, I am so afraid that I’m going crazy. my memory has always been bad, but now it’s at this whole other scary level. so bad that I’m making mistakes like this with my insulin. Over the years I”ve thought that my scatteredness was the result of anxiety or maybe ADD, but now I’m wondering if the real issue is brain damage from so many lows. I actually get really panicked, like how am I going to perform at work and take care of my kids if this continues? Can these effects be reversed? Your stories have hit home and are terrifying.

  • Gae

    I have been diabetic since I was 12y/o with Type I diabetes. I am now 57 y/o I have gotten by well, except always struggled to keep those blood sugars down. I have never really been in the range the docs want, but HA1C’s have been okay. But now I am noticing I can’t remember anything for more that the second it takes me to move to some other thought or project. If someone gives me a few minutes I can come up with the word usually. Also my neurologist says I have had a mini-stroke which is still being evaluated. I will see a neuro-psychiatrist which I hope will give me some understanding of what is happening and if there is anything I can do about it at this late date. I have to work, I need to be somewhat sharp. I manage, but I always hear myself saying oh I forgot that, etc. Sometimes I think it is just because I am not being mindful of what I am doing. My work moves so fast this is probably true. I know I need to excercise and eat more vegetables, but due to my biopolar diagnosis I found some of these extremly difficult to do. I am easily overwhelmed, noise bothers me, etc. But I will do what I have to do to improve if this is a possibility. I am changing my mind set to be a positive person and expect the best. I find this very comforting.

  • Joy

    I am 21 and have had type one diabetes for the last 18 years. It is good to hear from others who have had real bad low blood sugars too. Sometimes it feels like I am the only one out there who goes through this, but reading what everyone else has written hits home. I have had a total of five low blood-sugars that have required help from family and friends. Nothing is more scary or humiliating!!!!!I got an insulin pump two years ago and that has helped a ton with keeping tighter control. Also checking my blood sugar a couple of hours after I go to bed helps me catch lows before they get to low. It seems to take me a good week before I am able to function again, but this last time I went real low, it seems to have been a lot harder to get back to “normal” mentally.I will just keep doing everything I can to have the tightest control possible. I am not going for perfect, just so I can function and keep doing the things I love.

  • tina

    My husband is 50 and was diagnosed with type 1 just before he turned 3. In the past 20 yrs I cant count the number of lows he has had. Most people arent aware of hypoglycemia unawareness. Every diabetic is different. The more he tries to control his sugars the more episodes he has. His episodes are never the same. He can be 30 and walking and talking or be 40 and seizing or unconscious. He packs the same lunch every day at work but sugars vary from high to lows. 2 weeks ago on the way home from work he was stopping at a drive thru for food when he put the car in reverse and hit the vehicle behind him and passed out. The vehicle was paramedics. They got out because he hit them and found him passed out. They checked his sugar and it was 7! They treated him with d50 as soon as the got the IV placed. He was very lucky they were there when it happened or he could be dead or in a coma. There has been so many similar incidents over the years that its a miracle he is still with us. You cant treat your lows if you are unaware of them. Our daughter was diagnosed with type 1 at 5. She is 15 now and continues to have highs and low. Elementary school was rough. I was called by the school nurse almost on a daily basis and told what a bad parent I was multiple times. She would have unexplained highs and lows. She has been hospitalized multiple times. Anytime she is sick, even a urinary tract infection makes her sugars go haywire. She was low fri, mon and tue morning before school. Wed morn ok. This morn, thur, low. she was 47 and combative, nonverbal. She had to be fed like a baby and when I didnt get the food to her mouth fast enough she tried to take a bite out of her cat! There have been times she was in the teens or 20’s and walked and talked and got her own food. Its so frustrating! And her dad was 37 at 1:30 this morning and treated himself and called me at work to tell me about it. Nobody understands the impact of this disease unless they deal with it personally.

    • Tangia

      Diabetic for 35yrs. Now 50 no complications. Severe low bs several times a wk. Peak of long acting complicated. Humalog kicks me big time. Having to take Humalog to cover carbs I eat not the calories. I eat all day long anything I want. Prefer to have the lows even with the memory loss. Better than running sugar & having complications with kidneys, eyes, gangrene & hardening of the arteries. Not like I want to remember anything any ways. I usually yawn alot when low. Other times I just stop & stare or drop to the floor. Have had a lot while sleeping. With sweating profusely. Whole body muscle cramps like synide poisoning. I definitely can not live alone. 8 different EMS know me by name. I want the Dexcom G4 to help me with the lows but my endocrinologist states its would be a hazard for me because I would double stack my insulin. Told her she was crazy. I know how insulins work & peak. Told her I get 3 to 4 doses out of my glucagon. She said no you don’t. I said I have been doing it since it came out in 2005 or 06. I was happy on NPH. These new insulins are scary. Endo wanted me to try Toujeo which I said this is 3x’s the concentrate of what I am taking. How much should I adjust. She said oh the pen self adjust. The pharmacist said she doesnt know what she is talking about. Glad I researched it. On instructions it states specifically to reduce your dose to 1/3rd or 1/2 of what you normally take. If I would have taken the amt prescribed I would dead. My dad died at 36 for diabetes as related to CAD & only taking one shot a day. My mom is type II but on insulin. Her CHoL been high for yrs & she has been running sugar. She had a bypass, gall bladder removed, arteries in neck excavated (doctor brought out a bone from her carotid artery. Looked like bone marrow hard calcification with holes), gortex from her artery in one leg to the other, arteries are blocked all over, she’ll be on dialysis within 5yrs. I got on Crestor at 38. Most diabetic die from CAD. It a scary disease to deal with but everyone has something they have to endure.

  • Diane

    my sister had an episode on November 25th when i found her on the floor in her bedroom suffering from low blood sugars. She appeared to have suffered a seizure. She to this day suffers from major short term memory loss & trouble calculating carbs & insulin numbers in order to manage her type 1 diabetes. She is unable to drive & has lost her job. Your article sounds hopeful as she was one with many low blood sugars over the years but i feel that there is definite brain injury that may not be reversible.

  • Tammy

    Glad to see the postings! I have mre then my share of lows! I have been a diabetic for the last 34 years and the last 25 have been full of lows. My last low was 11. My daughter found me 14 hrs after I went low and ended up in the hospital and now have lows daily! And was told I had brain damage from the 11 I had that ended me up in the hospital. So yes lows can cause brain and memory damage. I have horrible short and long term memory.

  • Rose

    Seeing these comments makes me feel less alone!Sorry to see some of you in America with all these hefty bills – doesn’t sound fair! Luckily I’m English and we have the wonderful NHS.

    I’m 24, and have low blood sugars (below 3mmol/L) probably about 4-5 times a week, and in some weeks more than daily. In the past I’ve literally collapsed in the street because I didn’t realise my blood sugars were so low (probably below 1mmol/L).

    Whilst at university my control on low blood sugars got really bad and in 5 years I had maybe 6-7 seizures with 4 ending up with me in the emergency department. Probably the worst recent one was a couple of years ago where I had severe memory loss, which I regained over the next two days. Last year I was having hypos every single day, and I had another seizure and had to go to A&E AGAIN!!! It really started to affect me emotionally. I got quite depressed and cried in public a few times when I went to buy some food to raise my sugars.

    After my most recent seizure back in November my GP referred me to a consultant neurologist at the hospital who did some very basic tests, but did not allow me to fully articulate how I felt, and how I felt my cognitive abilities were lessening. I could no longer remember names of well known actors, artists or musicians for example, and that was something I always knew. I think because I seemed normal he thought I was fine, and sent me on my way. I find it quite distressing and upsetting because you are your brain, and it really feels broken and I’m only 24. I like the article but maybe for people who suffer with really severe hypoglycemia the effects are different. For the sufferers the effects are also very real and tangible, and obviously affecting lives.
    Also to Mark W i know what you mean about the trance like state – they are so incredibly frightening it fells like you’re dying and having a nightmare where reality warps all at the same time:( but then you get some sugar in you and boom! All is good! I used to have night terrors with my hypos as a child (8yrs) so they are bloody scary.

    • Sandra

      Absolutely, and oh my goodness at the same time! I have had type1 diabetes managed aggressively after waking up from a coma where my blood sugar was over 2000. I was in a coma for ~3 days as they safely, very much thankfully, got me out of the hyperglycemia. Yet, at that point my parents strictly controlled my diabetes from the day of diagnosis until I attempted to take over controlling my diabetes, brittle diabetic as I was from day one. I often find that stress/hormones can have a tremendous affect on your control. I have had diabetes for over 33 years, being 42 now and yet, I guess, thankfully my a1c’s have never gone above 7.5 – but it is getting more and more difficult to control. Medicare is not covering continuous glucose supplies, which have tremendously helped me not wind up in the ER a couple times a month. PLEASE CONTACT YOUR CONGRESS PERSON ABOUT GETTING ALL DIABETIC SUPPLIES COVERED. I am becoming close to broke and am having memory issues that I fret are because of my repetitive severe hypoglycemic reactions I am prone to. Help!

  • Patricia

    Hello there. I am a type 1 diabetic and have been for 28 years. I am 46 now. I have been in tight control with A1Cs around 6.3. Within the last few months everything is going crazy.I am having severe lows. Had my first ambulence visit to my house just yesterday. My husband came inside our room to find me lying in bed in a mild seizure. I remember nothing after I went to bed the night before. Woke up staring at 4 unfamiliar faces and crying in pain. I was………..am still terrified to go to sleep. Why can’t I feel the lows coming anymore? What has changed? I feel lost.

  • Patricia

    Hello there. Me again. OMG!!! It was my glucometer. It was all messed up. I wasn’t doing anything wrong. What a relief.

  • A B

    My wife of 16 years has type 2. She is insulin dependent. Some doctors she has gone to had her taking 75 units of humalog, 3 times a day.
    One night in 2012, i awoke to find her making grunting sounds and I could not arouse her.I called 911.Her blood sugar was 27. A few nights later the same thing happened. It was not long untill she was having problems with her memory.

    I took her to a neurologist. he did a brain scan,and told us with alzheimers there is brain shrinkage. Hers was normal. I then starting taking her to a shrink,who I was told was very good. After 8 months I now find that he is only a pill pusher. Tonight she is in the hospital and will be transferred to a psychiatric hospital and checked for brain damage and for them to place her on the correct medication.I Pray that she will recover.
    If you are diabetic check out what you are being told by your doctor. Do not be afraid to geta second opinion.It is your health and life that is at stake

  • Erica W

    Sarah Smith –
    When I found this article on a Google search, I also saw a lot of articles about “neonatal” and “prenatal” low blood sugar or hypoglycemia, and long-term effects. These might be more useful to answer your question about the infant, as the studies specifically relate to younger, developing brains.
    I hope you will find practical advice, and not fall into depression or worry. We all have to move forward from where we are; regrets don’t help much, especially if they become a “substitute” for effective action in the present. Children’s brains develop in all different ways anyway, so I hope you and your family continue to enjoy and support each other, regardless.

    I am lucky enough not to be diabetic, but I have hypoglycemia, diagnosed in my early 20’s about 15 years ago. I gave up refined sugars about 10 years ago, and it has made a huge difference to my energy and awareness. If I eat sugar by accident, I can tell the difference within a few minutes and remain extra susceptible and dopey for about 24 hours. I also have some difficulty waking up in the mornings, and it’s nice to know there’s a reason and remedies. I have been lucky enough not to have any serious episodes.

    I read this article looking to see if I’m risking worse effects if I sleep late on weekends … and have come away very grateful that my condition is as manageable as it is. People who thrive and raise healthy children despite the challenges of diabetes have my utmost respect.

  • michelle

    I have had very brittle diabetes now for 17years in and out of hospital, every time the doctors say they will be able to stabilize me, but after two to three weeks they give up saying the just don’t understand how my blood glucose levels can change so dramatic from 600mg to 0.02mg, which happen to me two days ago,i was admitted to hospital after a routine check because i was complaining of mouth abscesses, after speaking to the dental nurse so told me to go to A/E, just by chance the checked my blood sugars and my urine i was above 600 and had ketones i was in even DKA and did nt even know, i just felt ill and very tired. They then put me on an insulin drip glucose and something else, would nt allow me to eat or drink not even a sip of water, this went on for over 24 hours, they checked my blood sugars and urine and also did blood tests every four hours, i could’nt stop passing urine, my blood glucose came down bit by bit then i remember the nurse saying it was 55 so a asked her to please stop the insulin drip say said no, the next thing i remember is coming round with an oxygen mask around 10 people holding me down as i was fitting soaking wet very cold confused and covered in blood, i had be moved out of my bed and put on a trolley, i have no memory of what happen so think i must of been in a coma for how long i just don’t know i asked what happened and the only information they gave me was my blood glucose was 0.02mg which is basically nothing at all, my concern is since leaving hospital a day later i still feel really odd, very very tired, confused, irritable, headache, stomach ache just really unwell, my brain just is not working, writing this is really difficult as i keep forgetting how to spell words what am trying to say ect, should i go back to hospital and ask them to test my brain or will they just think i am being daft, also i keep having very low and high sugars more lows than normal, i am really terrified that something weird
    is going on, i need some advice please!

    • eileen

      Your nurse knew to administer sugar or glucose to you. Sounds like the insulin drip should have been immediately stopped. Sometimes we know our our own bodies better..

    • cptphdoif2

      You should definitely go back. You should clearly state that these symptoms emerged after the HOSPITAL INDUCED COMA. Then you should ask for a neurologic consult. You might want to consult a personal injury lawyer or malpractice lawyer to ensure that you are doing what you need to be doing to protect yourself should you have long term issues. It may be that this passes (the data from the study would suggest that it will) but just in case…

  • michelle

    I have had very brittle diabetes now for 17 years in and out of hospital, every time the doctors say they will be able to stabilize me, but after two to three weeks they give up saying the just don’t understand how my blood glucose levels can change so dramatic from 600mg to 0.02mg, which happen to me two days ago,i was admitted to hospital after a routine check because i was complaining of mouth abscesses, after speaking to the dental nurse she told me to go to A/E, just by chance the checked my blood sugars and my urine i was above 600 and had ketones i was in DKA and did nt even know, i just felt ill and very tired. They then put me on an insulin drip, glucose and something else, would nt allow me to eat or drink not even a sip of water, this went on for over 24 hours, they checked my blood sugars and urine and also did blood tests every four hours, i could’nt stop passing urine, my blood glucose came down bit by bit then i remember the nurse saying it was 55 so a asked her to please stop the insulin drip say said no, the next thing i remember is coming round with an oxygen mask around 10 people holding me down as i was fitting soaking wet very cold confused and covered in blood, i had be moved out of my bed and put on a trolley, i have no memory of what happen so think i must of been in a coma for how long i just don’t know i asked what happened and the only information they gave me was my blood glucose was 0.02mg which is basically nothing at all, my concern is since leaving hospital a day later i still feel really odd, very very tired, confused, irritable, headache, stomach ache just really unwell, my brain just is not working, writing this is really difficult as i keep forgetting how to spell words what am trying to say ect, should i go back to hospital and ask them to test my brain or will they just think i am being daft, also i keep having very low and high sugars more lows than normal, i am really terrified that something weird
    is going on, i need some advice please!

  • T Zandi

    I just completed a neuropsychological assessment of a 41 year old who had a prolonged episode of Glucose at 22, went into non responsiveness and stopped breathing for a while. she shows great deal of neurocognitive problems 5 month after her incident.

    • cptphdoif2

      Wonder if the cognitive problems are due to the low glucose or the hypoxia. Certainly if she stopped breathing hypoxia would lead to neuronal death pretty quickly.

  • Nyjil

    I read recently that one of the side affects of the newer “Insulin Aspart” insulins, like Novolog and Humalog, is that the users have hypo unawareness. I would like to know how many of the people who have posted here are taking these new types of insulin. They are all I have ever taken so I don’t have any experience with the other types.

    • Mack

      I take Humalog and Lantus. I have pretty good hypo awareness (I think). Usually I can feel it when im below 75. Anytime I’m below 60 I can almost always feel it (95% of the time).

      I even wake up when I start to get low blood sugar while sleeping. Usually I’ll wake up once I’m below 70, although this morning I got down to 50 before it woke me up….which is concerning and a bummer

      • Jon

        I am a type 1 using both Humalog and Lantus, and my hypo sensitivity is the same as you report. Thanks for your post.

    • RMT

      To be honest the human insulin has made a difference to unawareness. But in my 38 years of T1D I’ve lost awareness anyway. Various doctors have suggested running in the low double digits for a few months, but that’s going to cause issues down the line. So I’m testing a lot, regularly. I’ll run 12.0 – 13.0 before bed to avoid overnight issues.

    • Underdog Rising

      There is a link though it isn’t well established. The problem with human insulin is it just doesn’t absorb at a rate that mimics food metabolization. So lab created insulin has become much more popular since it mimics the natural rate of carb absorption.

  • Mr Rapapocalypse

    you should really consider having some sort of sugar arrangement on your night desk beside your bed :^)
    I also want to say i enjoyed reading your comment a lot. it was very thrilling. I am sorry that you’ve lead me to procrastinate even more instead of letting me do my homework… but that’s my fault. anyways, it was a good read.

  • Snowridge65

    Have you looked into the Dexcom Blood glucose monitoring system? It attaches to your body and the sensor that sits under your skin uses radio frequency to monitor your BG level. You still have to check your BG’s at least twice a day to keep it calibrated. You program it with the level you want to first be warned, say 95 or so, and then if you don’t do anything when it gets to 55 it lets out a loud shrill beeping sound that would wake the dead. It continues this way until your sugars start to climb up again. This way you can wake up and take care of yourself before it gets dangerously low. Also, why don’t you keep a big bottle of glucose tablets next to your bed? The orange flavor are quite good.

  • John Geiger


  • L. Boyer

    In reading your article, my granddaughter has severe hypoglycemia goes into the 30’s. And, she has had it go to the extreme 275+. She started having seizures a few months after birth. This continued for several years. Just in the past year the doctors have given her a diagnosis of idiopathic ketotic hypoglycemia.

    Last year a group helped to fund a service dog for her. It has warned the family. Her body fasts at night and wakes with low blood sugar. The last episode she went down to the 30’s and was rushed to Children’s hospital because she has seizures that come on with her blood sugar issues. The dog has been a blessing. Her dog had some training, and they had to continue the training at home. They have a retriever. Good luck in getting some answers. I think the medic alert would be great to have especially if you are alone!

    The dog can only warn you with barks, and pawing! They had to send in samples of her saliva…FYI

  • jean

    Try drinking at least 4oz of Glucerna each night if you have type 1 diabetes. Glucerna provides a steady release of sugar which could prevent low blood sugar.

    • Jon

      I have similar experiences as Joseph above. In addition, I experience very high blood sugars in the morning (5am) with or without low blood sugars during the night. Lantus seems to contribute to more low blood sugars at night, but does not seem to affect my highs at dawn.

      Wonder if anyone else experiences this.

      • Xiggy

        Hi Jon,

        I used to get the same thing… I’d check around midnight, and fine, but by around 5am high. My endo was convinced it was night-time lows, but I started checking a few times during the night and it was always just normal or good around bedtime to just past midnight (70-100), then up and up and up. I later realized it was correlated with eating out at restaurants… even if I ate “healthy” things like salad or beans or soup or something like that, there are almost always tons of hidden fats in restaurant foods simply to make them taste better. So, the glucose release from the food was so slow that it required an extra bolus well after dinner time.

        Actually more accurately, what the whole situation required was that I just stopped eating out at restaurants. I have the problem almost never now, unless it’s related to a night-time low.

  • kevin t niesen

    I’m a type 2 diabetic and have a1c of 6. But I have had times my sugar has dropped to 25 to 30. My main issue is my one touch meter will read 53 then 500 15 seconds later WTF! I originally didn’t know of there issues until a read an article on one touch. They supplied me with another meter and the same thing happened it read 250 so I dosed for that and my sugar went to 32. So now I have to test 3 or 4 times to get a reading I think is right. I used to have the breeze strip and never had an issue, but like all diabetics know insurance companies will only pay for the best deal they get. I have change meters and strips 5 times in 5 years because they seem to change due to the deals they make with companies. So since I have the POS one touch I have to test 3 or 4 times before taking insulin. So now I have to buy 200 strips a month. One touch aka Johnson and Johnson told me I must being something wrong. I have done this 1000;s of times and only had issue with one touch virio/iQ. By the way they gave me 10 free strips! WOW, that’s 2 samples since I have to do 3 to 4 strips per test. Like the problem they had before with a person taking too much insulin due to reading that was way off (he or she died). So be aware of this because I’m afraid others will die from accidental overdose

  • Underdog Rising

    You really need to delete this article or post a edit in the light of newer evidence. People will see this and think that having glucose below 70 is non damaging. If anyone reads this I insist that you research this with newer studies in mind. Just google hypoglycemia early onset dementia. This was posted in 2007 when not much research had been published. The ADA pushed recommendations for A1C of T1 from 5% to 6% recently. This had a lot to do with this research. Researchers found that those who’d experience a serious episode of low blood sugar had twice the risk of developing dementia (34 percent vs. 17 percent) than those who never had a hypoglycemic episode. It makes sense to. Your brain is just 3 pounds but takes up 20% of the energy you produce in the form of glucose. It needs a lot of it constantly to function properly. So having lows frequently damages cells who carry extremely complex functions. These cells can change the way your brain works which slowly leads to cognitive problems later in life.