Low blood pressure is caused by several things. Obviously, low blood volume and that needs clinical investigation. We would need to check your hematocrit (the number of blood cells compared to the volume) and the hemoglobin and red blood cell count. We would also need a urinalysis to determine the specific gravity as the kidneys may be involved. There are also hormonal secretions that may reduce the pressure...adrenal glands are responsible for maintain pressure, and the thyroid gland may also be involved. Fixing it depends on the cause. The cause requires a physician. Some individuals tend to have a normal low blood pressure or others may develop postural hypotension.