Diabetes mellitus leads to persistently elevated blood sugar levels. Over time, high sugar levels damage the body and can lead to the multiple health problems associated with diabetes.
But why are high blood sugars so bad for you? How much sugar in the blood is too much? And what are good sugar levels, anyway? WebMD takes a look at how your sugar level affects diabetes and your health.
In every issue of WebMD the Magazine, we ask our experts to answer readers' questions about a wide range of topics. In our January-February 2011 issue, we asked WebMD's diabetes expert, Michael Dansinger, MD, to answer a question about the link between prediabetes and diabetes.
Q: At my last checkup, my doctor told me I have prediabetes. Does that mean I'll ultimately develop diabetes?
A: Almost everyone who develops type 2 diabetes develops prediabetes first. But not everyone who has prediabetes...
At present, the diagnosis of diabetes or prediabetes is based in an arbitrary cut-off point for a normal blood sugar level. A normal sugar level is currently considered to be less than 100 mg/dL when fasting and less than 140 mg/dL two hours after eating. But in most healthy people, sugar levels are even lower.
During the day, blood glucose levels tend to be at their lowest just before meals. For most people without diabetes, blood sugar levels before meals hover around 70 to 80 mg/dL. In some, 60 is normal; in others, 90. Again, anything less than 100 mg/dL while fasting is considered normal by today's standards.
What's a low sugar level? It varies widely, too. Many people's sugar levels won't ever fall below 60 mg/dL, even with prolonged fasting. When you diet or fast, the liver keeps sugar levels normal by turning fat and muscle into sugar. A few people's sugar levels may fall somewhat lower. Without taking diabetes medicine, though, or having uncommon medical problems, it's difficult to drop sugar levels to an unsafe point.
Sugar Levels, Diabetes, and Prediabetes
Sugar levels higher than normal mean either diabetes or pre-diabetes is present.
There are several ways diabetes is diagnosed:
The first is known as a fasting plasma glucose test. A person is said to have diabetes if his or her fasting blood sugar level is higher than 126 mg/dL after not eating -- fasting -- for eight hours.
The second method is with an oral glucose tolerance test. After fasting for eight hours, a person is given a special sugary drink. That person is said to have diabetes if two hours after the drink he or she has a sugar level higher than 200.
The third way is with a randomly checked blood sugar level. If it is greater than 200, with symptoms of increased urination, thirst, and/or weight loss, that person is said to have diabetes. A fasting sugar level or oral glucose tolerance test will be needed to confirm the diagnosis.
Get the latest Diabetes newsletter delivered to your inbox!
Your level is currently
If the level is below 70 or you are experiencing symptoms such as shaking, sweating or difficulty thinking, you will need to raise the number immediately. A quick solution is to eat a few pieces of hard candy or 1 tablespoon of sugar or honey. Recheck your numbers again in 15 minutes to see if the number has gone up. If not, repeat the steps above or call your doctor.
People who experience hypoglycemia several times in a week should call their health care provider. It's important to monitor your levels each day so you can make sure your numbers are within the range. If you are pregnant always consult with your health care provider.
Congratulations on taking steps to manage your health.
However, it's important to continue to track your numbers so that you can make lifestyle changes if needed. If you are pregnant always consult with your physician.
Your level is high if this reading was taken before eating. Aim for 70-130 before meals and less than 180 two hours after meals.
Even if your number is high, it's not too late for you to take control of your health and lower your blood sugar.
One of the first steps is to monitor your levels each day. If you are pregnant always consult with your physician.
Thank you for signing up for the WebMD Diabetes Newsletter!
You'll find tips and tricks as well as the latest news and research on Diabetes.
Did You Know Your Lifestyle Choices
Affect Your Blood Sugar?
Use the Blood Glucose Tracker to monitor
how well you manage your blood sugar over time.