Complications Introduction Some factors that affect the blood sugar levels are food, exercise, and insulin. Too little food, exercise, and insulin lower the blood sugar level to abnormal levels. Too much will raise the blood sugar to abnormal levels. Stress also needs to be controlled. Too much stress will make the heart pump faster making the blood sugar level go up. In diabetics there is a higher risk for damage to the blood vessels. This can interfere with the normal heart flow and hurt the body’s tissue, which can cause heart disease, stroke, kidney disease, or blindness. This risk can go down if the diabetic does what their doctor says.