Q: My lab work says that a blood glucose level in the 60s mg/ dl is normal, but I’ve always been told that anything below 70 mg/dl is too low. Which is correct?
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A: There is a great deal of debate in the medical/scientific world about the true definition of hypoglycemia (low blood glucose). For anyone at risk of hypoglycemia, including those who take insulin or medications that increase insulin production, the general rule has always been that anything below 70 mg/dl is considered too low and should be avoided. Glucose levels below 70 mg/dl will usually cause the body to produce adrenaline, which leads to the classic symptoms of hypoglycemia (e.g., shaking, sweating, rapid heartbeat, intense hunger).
While these symptoms can be unpleasant and disruptive, they are not necessarily dangerous. Research has shown that, for most people, the mind and body can still function reasonably well even with glucose levels in the 60s. However, once glucose dips below 55 mg/dl, things change dramatically. At this point, the brain lacks the energy to function properly. Confusion can set in, and it may become difficult or impossible to eat or drink something to treat the low. And some people experience this at levels higher than 55 mg/dl.
Given how quickly glucose can drop, most people aim to keep their levels from going below 70 mg/dl. Think of glucose levels in the 60s as a guardrail that keeps you from falling over a cliff. You’re safe as long as you stay behind the guardrail, but if you push against it too hard or lean too far over it, you can easily wind up falling into a pit of doom. Best to have a discussion with your diabetes care team to determine precisely how low is too low for you.