Most of the time when we talk about blood glucose, we focus on making sure that it’s not too high. But it’s also possible for it to be too low—and low blood sugar is called hypoglycemia. Although it’s uncommon in type 2 diabetes especially for people who aren’t on insulin, it’s still important to understand the basics.
In general any reading under 70 is considered to be in the hypoglycemic range. Numbers below 60 are considered severe, and readings in the 30s can be extremely dangerous.
Common symptoms of low blood sugar include a feeling of falling, dizziness, rapid heart rate or confusion. Your hands might shake and you might feel sweaty around your face. And while these symptoms don’t feel great, they serve a purpose: your body is warning you of danger. It’s useful to know that these symptoms are not caused by the low blood sugar itself, but by your body’s response to it. This is important because your blood glucose may return to a safe range before your symptoms go away. This means you should not keep treating your low until you feel better, but rather treat it until your glucose returns to a safe range.
So what causes a low in the first place?
Hypoglycemia is most common in people with diabetes who use insulin, but can also occur when people take medications known as sulfonylureas. Taking too much insulin is a common cause of lows, and if you’re on insulin or a sulfonylurea, eating less or being more active than usual can cause your medications to lower your blood glucose too much. We have a list of common medications that can cause lows but be sure to ask your physician if one of your medications can cause you to go low.
Treating a low is easy. If your blood glucose is too low you need to eat or drink something that contains fast-acting carbohydrates. It doesn’t take much. 15 grams of glucose should raise your blood sugar by ~ 30-40 points. A small glass of juice, half a soda, or a few hard candies should do the job. You can also buy glucose tablets or liquids that work very well to raise blood glucose quickly. The amount of sugar you eat when you are low is important as you don’t want to eat too much sugar and have your blood glucose rebound and go too high.
As soon as you feel a low you should check your blood glucose so that you know what number is. If it is low, then drink or eat the sugar. After 15 minutes test again. It should now be above the low end of your blood glucose target range—for most people, that’s above 70 but be sure to ask your doctor what’s right for you. If it’s not there yet, you need to eat another 15 grams of glucose and contact your doctor.
If you take one of the medications that have a risk of low blood glucose, you should always have something with you like hard candies or glucose tablets that can treat a low.
So to wrap up… low blood glucose is most common in people who use insulin or take a medication from a class of drugs called sulfonylureas. If you’re on one of those medications, taking too much insulin, missed meals or increased physical activity can trigger a low. You treat a low by eating or drinking a small amount of sugar, waiting 15 minutes and then checking your blood glucose again.