Repeated Hypoglycemia May Not Cause Brain Damage

A recent study asserts that ".... the brains of type 1 diabetic
patients who suffer repeated episodes of hypoglycemia actually adapt
in a positive manner. The results of the study, published in the May
2014 issue of the Journal of Diabetes Investigation, … suggest that
the brain can increase its usage of alternative energy sources when
glucose is not sufficient, and this adaptive response can be promoted
by repetitive hypoglycemia."
For many years I have suspected this finding to be true. At the
present time I can have a hypo as low as the 30's gradually sneak up
on me and I do not notice. I have become so accustomed to these lows,
about three or four per month, that I can function very well, and do
not need help with them. If My BG drops faster I can feel them when I
am in the low 70's and have blurred vision. With a slow drop my body
and brain adjusts so well that I do not notice until I am very low. My
endo insists that I am having damage from these lows, but I do not
believe that. I had so many seizures from age six into adulthood, and
my mom, and eventually my wife, had to revive me with great
difficulty. I went on to six years in college and became a math
professor. My brain was not damaged, not at all.

Richard - Thanks for bringing this study to my attention. I’ve often wondered about the effects of the many hypos I’ve endured. I’ve only experienced about three episodes where I’ve passed out. But I’m sure I’ve had many more while sleeping.

Over the years I’ve often wondered about my difficulties remembering names, at times, could be attributed to diabetes. Perhaps these memory difficulties are simply the effect of aging or due to other causes. I also wonder about the long term cognitive effects of hyperglycemia.

Your long career with both diabetes and teaching math argues well that, in at least your case, hypos did not cause any cognitive deficit.

I know from my reading about low carb diets that the body can produce ketones that the brain loves to use as fuel.

Hi Terry, I still have lows in the 40s and 50s but they do not cause me any problem now. I have been retired for more than 10 years, so I can watch my numbers very closely. It was difficult to do that during my teaching years. I had a hard time remembering names of my students, but there were as many as 170 students each semester, so I did not feel guilty about that.

I hope your control will be good enough that you can avoid passing out.

I would tend to agree based on my experiences. I got on the pump because I had an A1C of 4.6, attributable mostly to lows, I was told. I have 1 or 2 bad lows a month, 30s or 20s, and rarely black out. Earned my Masters and worked in some fairly detail driven jobs and have never had an issue with memory or thought.

That sounds great, DDad. My memory is good , and goes wayyy back, but don't ask me what I had for breakfast. I do forget a lot of recent details like that.

This is great to hear. I’ve been hearing more and more over the last few years how bad lows are for my brain. Recently, I’ve heard “it’s like a concussion”. I doubted it. I guess I can see how a coma could cause some residual damage , but not common lows. I really prefer to keep my sugars on the low side, which often puts me below 60, but it’s so easy to fix with glucose, that I can’t see it being a problem. It takes so much longer to treat a high, and I feel much worse 180 or above. Good stuff

I think my Specialist is more concerned about my lows because I may fall , which actually did happen ( April 25 ) ,My vertebrae 8 collapsed and still has not healed ...BG was on the way down I am sure , while eating breakfast ...I recall testing , result was 3.7 ( x 18 ) . I am too happy to read about the study ...Thank you Richard !


I have been reading about this recently. My son and I, both Type 1's, he since age 4 and me age 38, have both had many many severe lows, losing consciousness and experiencing convulsions. Thankfully we are both on pumps and CGM's now. I used to worry about both of us suffering brain damage, as it seemed likely to happen. This is indeed good news!

This is great news. While I don't have severe hypos or even all that frequent ones (I'd say 2-3 never below 50 hypos a month) , it's good to know that it isn't the worst thing, makes me less anxious about dealing with them.

I agree that’s awesome data to have in our DataArmada! The main reason lows are characterized as “bad” is because of allegations of brain damage which are now found to be, well, unfounded. This is great news indeed. Thanks for sharing Richard!

Thanks for this info Richard. Like you and many others, I have had countless seizures as a Child and through the years. I have not suffered any negative consequence due to those seizures. On the other hand, I do not try to have low blood sugars cuz they mess up my day and make me feel badespecially if I were to end up in a seizure.

As you know, the one severe seizure I did have brain damage from was when a Nurse had given me my Insulin before breakfast(I was unconscious) and my blood sugar was only 1.5 mmol/l(27mg/dl). That was when I was about 31. I've not stayed over night in a hospital since. :)

“Tightening control also leads to an increase in hypoglycemic events,” Jacobson says. “We found a three-fold increase in the number of serious hypoglycemic event in the subjects who had improved blood sugar control.”

This I also agree with. That is why I do not agree with the "not over 140 mg" limit. Nice on paper but not in the real life situations for far too many Diabetics. I did hit the 5.3 A1c once but I won't be trying that again. More lows than I had in a long time.

Hi Terrie, I certainly agree. A nurse giving you insulin, when you needed glucose, is inexcusable!! I have never heard of that happening in my area, but I bet it has.

I had my A1c's in the 5.5-6.0 range for almost 10 years, with too many lows. My new endo insists that I keep my A1c in the 6.0-6.5 range to avoid lows. Guess what? I still have lows, but not any very low lows, so I guess things have improved. I have not needed assistance with a low since July, 2007.

Chad, ME too!

Dear Richard, as usual from you, what a great discussion, I have been pondering this very thing for a while now. I especially appreciate how you explained the difference between dropping low suddenly and very fast and going low gradually. YES!!!!! Exactly.
Love, Gina

What is interesting about this work is that it is basically an observational study. It looked for an "association." And it didn't find a clear association. Since an association was not found it could either mean:

Repeated hypoglycemia doesn't cause brain damage


Brain damage doesn't cause repeat hypoglycemia

(or both)

I, too, am retired. The ability to monitor/track my BGs without the distraction of a job adds immeasurably to my control. I realize this is off-topic, but my experience with BG control as my full-time job has been a real eye-opener to me.

Many here operate under the philosophy that diabetes does not hold them back from any aspiration in life. I wholeheartedly agree with that sentiment but it does have its drawbacks. While I worked I dealt with all the lows and highs that come with T1D. I did not, however, deal with these events in a timely fashion.

Timeliness is a hallmark of good control. Being retired allows me to watch my BGs much more closely and respond appropriately. Now when I see a slow steady BG upward march, I can counteract with an immediate walking session that almost always cuts off an impending BG mountaintop. Timely additions of insulin produce the complementary effect.

I didn’t come to this conclusion until I retired and suffered a diabetes complication. It wasn’t until that combination of events that I realized that, for the first time in my diabetes career, 30 years and counting, I had the opportunity to do whatever it took to regain very good control of my diabetes.

I apologize for the thread-jack! I couldn’t resist.

Yes, I'm sure it happens everywhere Richard. I cringe when I hear on the North American news how many People every year die because they are given the wrong medications, overdosed and so on at the hospitals. You're right, there are no excuses for it. Anyways, the Nurse who overdosed me was put on a six month suspension and a 3 month probation. I just hope she was told to refresh her knowledge on treating Diabetic Patients while she was off.

That's exactly where I like to be: 6.0 - 6.5. A safer place for me and my Endo is Good with that too. Great to hear that you have less lows Richard. Me too! :)

Hi Richard

Thanks for bringing this up. From my own personal experience I don't think lows cause brain damage, I like to think I'm still reasonably alert. I can go down to the 30s & still test & take a suitable amount of glucose without help. I'm trying hard to reduce these lows, but I don't consider a BG reading of 60-70 as a low. At the moment my Endo is trying to convince me that an A1C around 6 is too low at my age (71) & over 50 years T1 I should aim for 7.0. No way! I feel worse with BG over 200 than under 70. I also feel insulted that he thinks I can't cope.

Annabella, I wish that all of us type 1 folks could have an endo who is also type 1. That would make a big difference in their understanding our ups and downs, our lows and highs, and all the rest. I have a Facebook friend who is a type 1 endo. He has written many wonderful articles. It is a pleasure talking with him.

Fascinating information, Richard, thanks for sharing! I always appreciate the solid data you bring to the forum.

One word of caution, though: While I understand you don't believe these extremely low BG levels are causing any neurological damage (and 30 mg/dl is extremely low), there isn't the science yet to come to such a firm conclusion. While the article you shared is encouraging, it's just a fraction of the research that is necessary to fully understand this.

Also, variation in the population may be extensive. In other words, some people might not have any damage at 30, while others may suffer permanent problems from repeated bouts with 40.

So, I'd just caution everyone to not get sanguine about hypos, but to continue to agressively watch for, and treat them. Until we know much more about this condition -- and we know very little -- it's a toss of the dice every time.

Just my own variation in how I react to the same hypo levels on different occasions makes me cautious about believing I know enough about this aspect of my metabolism to relax my vigilance and response.