It is no surprise that anyone with diabetes worries about long-term complications, and many studies—especially the now-famous Diabetes Control and Complications Trial (DCCT)—have confirmed the importance of avoiding recurrent high blood sugar levels. The DCCT was also one of the first studies that emphasized the importance of avoiding low blood sugar levels, too, especially severe hypoglycemia.
Severe hypoglycemia is not defined by a blood sugar number, rather it is defined as the inability to independently treat a low blood sugar level. We now know that serious injuries can be caused by household accidents and auto crashes related to severe hypoglycemia.
Joslin offers a hypoglycemia prevention workshop based on collaborative research done over the past 25 years with the Department of Behavioral Medicine at University of Virginia.
Recognizing the Symptoms of Severe Hypoglycemia
The results of that research show that the most common symptoms of a low blood sugar (below 70 mg/dl) include feeling shaky, sweaty, pounding heart and lack of coordination. Yet, it is not uncommon for someone with diabetes to lose these classic symptoms over the course of time. In fact, it’s not unusual for someone with diabetes for many years to have lost, or have trouble detecting, the physical and mood changes caused by a low blood sugar.
Clinical research and my own experience working with diabetes patients here at the Joslin Diabetes Center indicate that even if physical symptoms and mood changes disappear over the course of time, the thinking symptoms caused by a low blood sugar do not fade away.
These thinking symptoms may become the best, and perhaps the only, symptoms of hypoglycemia for those who have had diabetes for a long time. Examples of these thinking symptoms are difficulty concentrating, slowed thinking or fuzzy thinking.
These symptoms typically start at a blood sugar level of 65 mg/dl which should be high enough for someone to independently recognize and treat the low blood sugar. Obviously, as blood sugars drop lower, thinking symptoms can become worse leading to confusion, disorientation and severe hypoglycemia, that is, the inability to think clearly enough to react.
Our research tells us that the most common reason for a low blood sugar (defined as less than 70 mg/dl) is taking too much insulin, and the second most common reason is not eating enough or delaying eating after taking insulin.
But the most common reason for severe hypoglycemia is delaying treating after recognizing symptoms. And not surprisingly, the most common mistake when treating a low blood sugar is over-treating.
Another common mistake is treating with something that tastes good like chocolate or ice cream rather than fast-acting carbohydrate. (The fat content in the chocolate or ice cream slows down the absorption of the sugar).
Our research also tells us that low blood sugars breed more low blood sugars, and the more lows that one has, the less symptomatic they become, and the longer it may take to bring blood sugars back to the normal range.
Our collaborative hypoglycemia research started back in the mid-1980’s with an initial study that found people taking insulin were not as accurate at detecting low blood sugar levels as they imagined. In fact, when asked to guess blood sugar levels based on symptoms before checking, they missed the number by a wide margin 55% of the time.
The most common mistake was that these adults thought their blood sugar level was okay when it was not (too low or high). Subsequent studies with children and their parents have had similar results.
The Risk of Injury
We know from research that most of the hypoglycemia related accidents during waking hours are from car accidents. For example, a few months ago the Boston newspapers carried a story about a woman who drove her car into her neighbor’s swimming pool during a severe low blood sugar. Fortunately, her neighbor was home and dove into the water to rescue her.
Our research has shown that drivers start to slow down to compensate for a low blood sugar, but they also start to swerve on the road. This is why there are now guidelines for driving that include:
- checking blood sugars before you turn on the car if you think you might be low.
- stopping as soon as possible if you feel low or someone else thinks you are low while driving.
- checking and treating low blood sugars, immediately and appropriately.
- waiting, as hard as that may sound, to start driving again until blood sugars return to a normal range.
During the night, the most common reason for injury is that people get up to go find some orange juice to treat their low blood sugar and end up falling down the stairs or having some other type of household accident. I recently saw a man who fell down the stairs and broke his leg on his way to the refrigerator for some juice. That’s why it’s important to have something right by your bed to treat a low blood sugar rather than find yourself roaming around the house, confused in the dark.
The ultimate goal is to reduce low blood sugar levels to as few as possible, although eliminating them is impossible if you are taking insulin and striving for tight control. However, the goal is to totally eliminate severe low blood sugar levels that can be potentially harmful, as well as distressing to both you and family members who may have to deal with them.