Thursday, January 26, 2012

What do you make of this? What do you call Low?

I've been listening to Robb Wolf's podcasts about eating Paleo diet and solving health problems. One reader asked about non-diabetic people testing their blood sugars and what he considered "normal". He said that with the non-diabetic athletes he works with it is very common for them to maintain blood glucose values of 60-70 mg/dl, all the time. These are insulin-sensitive, low-carb, ketogenic atheletes. I was fairly incredulous (almost mad?) because I have always considered those numbers to be uncomfortable low blood sugar numbers. Also, I have found Dr. Bernstein's standard of 85 mg/dl to be difficult to achieve, but this  60-70 mg/dl business just sounds uncomfortable!

I guess, if I had no chance of actually going hypo because of all the checks and balances (glucagon, etc) of a normal body working perfectly, I wouldn't be too freaked out to just walk around in the 70s all day. However, I do feel some minor hypo symptoms at that level and always correct to get my level back to 90-110 mg/dl.

So, that has me questioning my bias towards high-ish "normal" numbers, and also had me wondering if Robb was fudging numbers downward to make a point. When it comes to blood glucose numbers, we Type 1s are very aware of what is normal and what's not, so we don't go for exaggeration in the place where we live.

Then I saw this guy's graphs and read about him sleeping and waking up regularly with his glucose in the 60-70s. I just wondered, why would you do that? He says he felt better that way. Is that possible? So many questions... (just corrected my fasting 108 mg/dl down a smidge.)


  1. I used to believe that 60s and 70s were normal fasting blood sugar, until I started reading actual large population studies that looked at fasting blood sugar, and found that normal fasting blood sugar (that is, blood sugar for the vast majority of people without symptoms of diabetes or hypoglycemia) is actually very tightly in the 90s.
    It is normal to have postprandial blood sugars in the 60s and 70s (especially 70s); a lot of people have blood sugar three or four hours after a meal (the meals I've seen in the studies have more carbs in them than you eat in a day; I'm not sure if this would be true for a low carb meal but I doubt it) that is lower than what they start with. Also, people's blood sugar after many hours of fasting may be lower than "fasting" values and some people just run low.

    Sometimes when I read about nondiabetics with really symptomatic problematic low blood sugar I am amazed at how low they run. For instance, I recently read an article (written fifty years ago) about a toddler who'd had a handful of hypoglycemic seizures. His fasting blood sugar ranged from 9 mg/dl to about 70 mg/dl.

    Anyways- I think the preponderance of evidence is that a blood sugar of 70 produces absolutely no symptoms in anybody whose body is used to blood sugars of 70. Blood sugars of 60 may cause cognitive difficulties, including on simulated driving tests. Low blood sugar starts being dangerous for people who aren't operating motor vehicles around 45, which is when it starts causing abnormal EEG patterns. But like I wrote in my zine, sometimes people run much lower blood sugars without incident, and I've read numerous accounts of people without measurable blood sugar (or whose blood sugar was less than 10 mg/dl).

    But getting around to my personal comfort zone: if I had a meter that agreed within even 5% of the lab draws every time, I would be comfortable with blood sugar readings in the 70s. But in real life, I have twice had symptomatic hypoglycemia in the doctor's office with a blood sugar reading above 85 but a laboratory reading below 70. I treat everything below 90 as hypo, which I think is ridiculous, but it's what I can do.

    Also, I do need the safety buffer. Despite treating lows at 90, and despite using a Dexcom, I see LOW on my Dexcom about one day per week.

  2. I've done that myself, sleeping that Low - not actually trying to, though. I've heard some do because they feel comfortable doing so. The saying goes: Your Diabetes May Vary. To each their own. I've written about the different symptoms and names for Lows in the past.

  3. I have noticed that the fewer highs I have (even if we're talking about a 140), the less likely I feel low around 60/70. The time I got a 4.7 A1c (an experimental 3 months with an insane amount of testing) I was shocked to discover how good and energetic I felt around 70. Below that and I did feel low and fatigued. I wonder if those without any highs (something we type 1 diabetics cannot avoid from time to time) don't feel too bad around 70 because that's not a real "low" for them based on their range of say, 60-100? I wonder...and I wish there was more info out there about this. Right now, I'm not as tightly managed because my twins are driving me crazy and so I'm trying to accept 140-150 more often than I used to (temporary until they are a little older). Even now I find that I feel good purposefully sleeping with blood sugar around 80, which often means I wake up around 65-70, which then thanks to the dawn phenomenon lands me at around 100 by the time I've finished washing up and brushing my teeth. I know it's probably risky because I don't have any cgm and I risk having major lows at night, but I've been doing this for a few years now and I guess it's a bit of a routine. I'm really enjoying those podcasts by the way, thanks for mentioning them.

    1. Yes, good point, Sysy. I think there is a big impact on symptoms based on where you normally are. Now I just need to figure out how to get stable at 70-100. Stable enough to sleep...