Elevated blood sugar over time can lead to a complication that affects many systems of the body from the heart to the eyes. One way to think of this is to think of how sugar mixes with water. When sugar is added to water, the result is a thicker substance that tends to be sticky. When blood sugar levels remain high for extended periods of time, the blood becomes thicker and harder to pump or flow through the vessels. This causes distress on the heart and body. When blood sugars remain high, there also tends to be more of a congregation of blood fats which can lead to thinks like heart attack and stroke.