The dark color of blood is considered to be caused by blood viscosity, intestinal cyanosis, cardiac insufficiency and so on.
1. Blood viscosity: excessive red blood cell aging, red blood cell aggregation occurs, the human blood viscosity increases, the body tissue to obtain oxygen is relatively reduced, resulting in dark blood color.
2. Intestinal cyanosis: mainly due to nitrite food poisoning, nitrite oxidizes the divalent iron of hemoglobin in the blood into trivalent iron, resulting in methemoglobinemia, which will lead to dark blood color.
3. Cardiac insufficiency: heart systole-diastole disorder, resulting in pulmonary circulation stasis. The bruising of the pulmonary circulation manifests itself as dyspnea and insufficient oxygen supply, resulting in dark-colored blood.
If you find that the blood is dark in color, you should go to the hospital in time to check the cause of the disease, and should be treated symptomatically, avoid self-medication.