11-Headache
Another common symptom of anemia is a headache, and it is even more common than low concentration problems. Low oxygen levels in the brain trigger a dilatation of blood vessels as a way to increase the circulating levels of oxygen in the brain. Dilatation of blood vessels in the brain is the same way migraines are formed. They start pounding against the outer linings of the brain where the pain sensation is felt and trigger a headache. Keep in mind that there are many other causes of headaches, and it is a rather common symptom that requires medical attention to trace the cause.