Hemoglobin is a protein that the task of carrying oxygen from the lungs to other organs of the body to make plays. Lack of it is a sign of anemia, and increasing it is an indication the concentration of the blood.
the causes of its decline:
anemia, lack of elements of iron or Copper, Copper, lack of vitamin 6, B 12, etc., folic acid, and vitamins.
the causes of its increase:
use of tobacco, air pollution and lack of oxygen, etc.