What is the normal blood sugar range for healthy blood sugar levels AND what blood sugar range starts to become dangerous?
On January 11, 2008 ABC News Health interviewed Edward S. Horton, M.D. Section Head, Clinical Research at Joslin Diabetes Center, Professor of Medicine, Harvard Medical School.
When asked questions about what constitutes the normal blood sugar range for healthy blood sugar levels and what blood sugar range represents a dangerous (emergency) blood sugar level, Dr. Horton provided the clearest medical opinion we have been able to find defining exactly what the normal blood sugar range is. Dr. Horton’s quote below provides a clear explanation of exactly what constitutes a normal blood sugar range for fasting blood glucose levels and post-prandial (after meals) blood sugar range.
“Now, in a normal individual we measure blood sugar under different circumstances. What we call fasting blood sugar or blood glucose levels is usually done six to eight hours after the last meal. So it’s most commonly done before breakfast in the morning; and the normal range there is 70 to 100 milligrams per deciliter.
Now when you eat a meal, blood sugar generally rises and in a normal individual it usually does not get above a 135 to 140 milligrams per deciliter. So there is a fairly narrow range of blood sugar throughout the entire day. Now in our diabetic patients we see both low blood sugar levels that we call hypoglycemia, or elevated blood sugars, hyperglycemia.
Now, if the blood sugar drops below about 60 or 65 milligrams per deciliter, people will generally get symptoms, which are some shakiness, feeling of hunger, maybe a little racing of the heart and they will usually be trenchant or if they eat something, it goes away right away.
But if blood sugar drops below 50 and can get down as low as 40 or 30 or even 20, then there is a progressive loss of mental function and eventually unconsciousness and seizures. And of course that is very dangerous and a medical emergency.
On the other side, if blood sugar gets up above 180 to 200, then it exceeds the capacity of the kidneys to reabsorb the glucose and we begin to spill glucose into the urine. And if it gets way up high, up in the 400s or even 500s, it can be associated with some alteration in mental function. And in this situation, if it persists for a long time, we can actually see mental changes as well. So either too low or very exceedingly high can cause changes in mental function.”
*ABC News Health “What Is The Normal Range For Blood Sugar Levels, And What Blood Sugar Level Constitutes A True Emergency?”-Edward S. Horton, M.D., Section Head, Clinical Research at Joslin Diabetes Center; Professor of Medicine, Harvard Medical School, January 11, 2008