“According to biographer Taylor Branch, King’s autopsy revealed that though he was only 39 years old, he had the heart of a 60-year-old-man, evidencing the stress the 13 years in the civil rights movement had on him. It implies that in the 13 years prior to his death, he had aged 34 years or 2 1/2 times as much as a person living a normal life.” (Taken from Wikipedia).