When the Lows Don’t Represent

Blood glucose can be a fickle thing. At least, for those of us with diabetes who manage our condition with medication, diet, and exercise, blood glucose numbers can seem to, of their own caprice, dive precipitously with no rhyme or reason.


Fortunately for most of us — around a fifth of people with Type 1 diabetes exhibit hypoglycemia unawareness — the warning signs of a low blood glucose (hypoglycemia) show up and nudge us in a corrective direction. Hunger, often an eat-the-shelf type of hunger (fridge shelf or pantry, or both, take your pick), sweating, the feeling of weakness or loss of some cognitive function — such as having trouble speaking — are some of the symptoms we have all experienced.

For me, I’ve come to learn that a lightness in my legs that then creeps up into my belly shows up when I’m around 70 mg/dl. At that point it’s not going to be long before I go clammy. Legs, back, shoulders… I’ll begin to feel as if I’m coming out of a bad dream in the heat of the summer and the night sweats are upon me. I need food. I need carbohydrates. The Incredible Hulk of Hunger emerges and it’s quite difficult to beat that beast back down once it’s unleashed.

That is why I try to stay on top of any initial low blood glucose warning signs and treat them with 15 grams or so of carbohydrate, as well as make sure to check my blood glucose as often as possible. I am, however, mortal, and therefore I’m going to make mistakes. Sometimes I’ll overbolus, or I won’t prepare adequately for a workout. Or I’ll (stupidly) stack a bolus when the first one doesn’t take as quickly as I think it should (insulin or bolus stacking, quickly, is “the practice of providing correction-dose insulin before a prior dose of prandial insulin (or the peak action of NPH insulin) has had its full effect,” a definition I pulled from here). I own up to those mistakes, and when a low happens because of these things I have done, or haven’t done, I learn, and I try not to do that ever again.

Yet I’m also a person with diabetes who uses insulin, who doesn’t have a fully functioning pancreas. I’m a person whose body just doesn’t work correctly. So no matter how careful or aware I try to be about what’s going on with my blood glucose, and no matter that I’ve tried to do everything the same way I’ve done these same things every day for the past two months or two years, there is an aspect of the body and environment and ever-so-slight — most often imperceptible — deviation from routine that has the potential to turn a happy, normal blood-glucose number (and thus a functioning and normal Eric) into an unhappy, low blood glucose number (and thus a less-than-stellar Eric) well inside of thirty minutes. Maybe sooner.

The problem is that sometimes this transition from good blood glucose to bad blood glucose happens so quickly that I don’t get the body’s normal hypoglycemic warning signals. Or… or as happened recently, I get different warning signals that I haven’t yet learned are warning signals. Last week, for example, I was working out at the gym. I’d had two bananas in the half hour before I started exercising. I’d set the temporary basal rate on my insulin pump to about 60% of the normal rate three to four hours prior to working out, and I checked my blood glucose several times in the thirty minutes before exercising. Everything was copasetic.

About 45 minutes into my routine I get really tired. That’s all. Just tired. No weak legs. No sweating. No feelings of ravenousness. OK, I admit: after a ten-minute cardio warm-up and thirty minutes of lifting, yes, my legs might be tired, but they didn’t feel weak in the same way a low feels; and yes, I was already sweating, but sweating from exercise, from exertion, which is much different than the clammy low-blood-sugar-imminent beady sweat that I know all too well.

I speculate that the exercise masked my normal symptoms. At some point way back when I first got diabetes and was over-reading everything I could get my hands on, I read about this and I knew this could happen. Except I’d since forgotten. I’d grown complacent. And I was working out in ignorant bliss because my routine had been going so well, moving along for months without insult or injury.

Then that tired hit me. The yawn. Such a fit of yawning mid-set. Yet I wasn’t tired. It was that my blood glucose had dipped to about 66 mg/dl. I know, because eventually I grew suspicious and went into the locker room to check my numbers.

The only thing I recall that could have tipped me off to these numbers was my yawning. Hard yawning.

Yawns are now part of my mental checklist of possible low blood glucose indicators.

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  • Natalie Sera

    Exercise is absolutely the worst time for me to catch the symptoms of ANYTHING — I don’t feel lows until after I stop exercising, and I don’t feel exhausted (like I’ve overdone it) until after I stop. I have a CGM, and it is helpful to know whether I’m maintaining or going down, even if the numbers lag behind actual BG numbers. If you don’t have a CGM, regular BG checks during exercise might be a good idea, if you can take a break.

  • jim snell

    I agree with Natalie. Issue is that one can flatten available blood glucose on exercise easily.

    My doctor has me watching BS and does not want it under 100.

    When it is at 170 and up, I can walk the 1/4 to 1/2 mile or sweep up the leaves. When its at 140, I easily crater that number. It is like steam engine, for good A1C / BS numbers, one needs small fire and sugar supply.

    Minte one exercises, you need real boiler load – glucose – 180.

    With insulin pressure – humolog/lantos, starlix pill
    glucose can head to basement fast at low BS numbers
    under 140 under exercise

  • mary little

    that happened yesterday..no rhyme or reason..out shopping..enormous chest pain and back pain and all the other symptoms..SUDDEN ONSET and trying to find a place to sit no monitor as i was trying to lighten the carry load for going to the p.o. with boxes..whatever it got down to it took 45 minutes to bring it back to somewhat functional and scared me half to death and i contemplated having someone call an ambulance for the first time in a twenty year experience with the diabetes slept through the rest of the day and into this morning and still exhausted..i thought for sure i was dying lol

  • Arlene Walker

    My husband is a Type 2 Diabetic. I am, what our doctor calls, Glucose Intolerant. My husband can hit a low and not even realize that he is low. I, on the other-hand, get dizzy, weak, etc whether I am having a low or what is a high for me. It is really bad for me when I get upset or have been on the go for awhile. It is like my body betrays me. I need that little extra boost and my body says NO WAY. So, of course, I need to check my BS. I check mine when I first wake up, before each meal and about two hours after I finish supper each night. But, on my bad days, I end up checking between these times also. I never know what it will be, by how I am feeling, since I feel the same whether it is low or high. But I make very sure that I have my monitor whenever I leave the house. I don’t need to be stranded without it and end up in trouble. I would rather be safe-than-sorry.