Diabetes is a chronic medical condition that affects how your body processes blood sugar (glucose). Glucose is an important source of energy for your body's cells, but to function properly, it needs to be regulated within a certain range. In diabetes, this regulation is disrupted, leading to either high blood sugar (hyperglycemia) or, less commonly, low blood sugar (hypoglycemia). Over time, poor blood sugar control can lead to serious complications affecting the heart, kidneys, eyes, nerves, and other parts of the body.