Blood sugar measure the concentration of glucose (sugar) in your blood stream at a given time. There is a normal amount of glucose that's typically found in the blood of mammals (including humans); any levels that are above or below the normal range may indicate a health concern, and probably deserve futher investigation.
A normal range for human glucose levels will vary depending on the person, as well as on things like diet and time of day. Someone who recently consumed carbohydrates will have a higher glucose level, since carbohydrates are how glucose gets into the body. Once it enters the body, a hormone called insulin, which is produced by the pancreas, releases itself into the blood stream to regulate the glucose amouont and keep it within the health range.
For some people, however, insulin doesn’t release like it should and this can result in more glucose than may be healthy remaining in the blood stream. A normal glucose level will fall anywhere between 70 and 150 mg. Anyone whose level is consistently above 150 mg should likely be considered as having high blood sugar, which in turn could be both a sign of and a risk factor for diabetes.
For example, if you test your blood sugar and you get a reading of 170 mg, you shouldn’t immediately assume that a blood sugar level of 170 means you have diabetes. The truth is that people with regular high blood sugar, or even those with normal blood sugar, can at times reach very high glucose levels, particularly after meals high in carbohydrates.
For the most part, a normal-range person’s levels will not rise above 140 or at most 150, but it does happen. The key thing is not necessarily how high the sugar rises, but how often it does so, and how quickly it goes back to normal.
See blood sugar in American Heritage Dictionary 4
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