Hyperglycemia is a medical condition characterized by high blood sugar levels. It occurs when there is an excessive amount of glucose in the bloodstream, which can be caused by various factors such as insufficient insulin production or resistance to insulin. This condition can lead to symptoms like increased thirst and urination, fatigue, blurred vision, and slow healing rates. It is important for individuals with hyperglycemia to manage their blood sugar levels through diet, exercise, and medication in order to prevent long-term complications such as heart disease or kidney damage.