"Borderline" diabetes is also called "pre-diabetes." Here, blood sugar levels are slightly higher than normal. But they are still not as high as in diabetes, and not high enough to cause symptoms. People with pre-diabetes have a higher risk of heart disease than average, even before diabetes develops. Most people who have pre-diabetes will get diabetes.
Normally, the pancreas makes and secretes just enough insulin to maintain adequate blood sugar levels. Insulin helps sugar move from the blood stream into your cells.
In pre-diabetes, the body's cells become less responsive to insulin. This is called insulin resistance. Blood sugars start to rise. The pancreas compensates by putting out more insulin. But now the pancreas is always playing catch up to higher than normal blood sugars.
Insulin resistance usually gets worse slowly as you age. It also gets worse with weight gain. If your cells become so resistant to insulin that your pancreas can't put out enough to compensate, you will eventually have diabetes.
With pre-diabetes, you have about a 10% chance of getting type 2 diabetes within one year. Your chance of getting type 2 diabetes during your lifetime is roughly 70%.
Fortunately, good diet and exercise habits can help delay or prevent type 2 diabetes. People with pre-diabetes should lose 5% to 7% of their body weight and exercise at least 30 minutes a day. Research has shown that these changes can lower your risk for diabetes during the next 3 years by almost 60%.