Video: The Great Migration: Definition & Causes. The economic conditions of World War I led to a massive movement of African Americans from the South to the North, known as the Great Migration. Examine the causes and effects of this phenomenon.
Physicians may want to look closer at WBC levels when obtaining the tests for other reasons, Manson notes. However, infections can cause a high white blood cell count that may make it appear that a patient is at high risk for heart disease when she is not. Therefore, routinely giving everyone the test to screen for heart disease is premature. More research needs to be done..
During exercise, your heart rate increases to provide your body with enough energy to perform work. Your level of fitness directly affects your heart rate, which tends to increase if you're overweight. An increased resting heart rate puts more stress on your heart during and following exercise.