Elevated erythrocytes, medically termed erythrocytosis, refers to a condition where the number of red blood cells in the blood is higher than normal. This condition increases blood viscosity, thereby raising the risk of blood clot formation and potentially leading to various health complications such as heart conditions, polycythemia (a bone marrow disease), lung diseases, and kidney problems. Common causes of erythrocytosis include decreased tissue oxygenation, excessive whole blood transfusions, chronic smoking, strenuous physical activity, and hemoconcentration. Furthermore, factors such as dehydration and sleep apnea can also contribute to increased erythrocyte levels.