The Progressive Era. During the period known as the Progressive Era (1890s to about 1920) the U.S. government became increasingly activist in both domestic and foreign policy.
One possible link between brain freeze and other headaches is local changes in brain blood flow. If further research confirms all these types of headaches are caused by blood flow changes, new drugs that block widening of the blood vessels - called vasodilation - could improve treatment for sufferers.
Some of the factors concerning the brain that can trigger blackouts include insufficient blood supply to the brain, epilepsy, hypoxia, cerebral hemorrhage, arrhythmia and any injury to the head. Excessive degree of physical stress and/or emotional stress can also serve as a trigger to this medical condition.