Pre-Algebra on Khan Academy: No way, this isn't your run of the mill arithmetic. This is Pre-algebra. You're about to play with the professionals. Think of pre-algebra as a runway.
Coronary heart disease. Coronary heart disease (CHD) is the leading cause of heart attacks. CHD is a condition in which the coronary arteries (the major blood vessels that supply the heart with blood) get clogged up with deposits of cholesterol. These deposits are called plaques.
Proof that stress really does cause heart attacks: Adrenaline can increase white blood cell production which can cause ruptures. 1  Extra white blood cells can cause inflammation in people whose arteries are already thickened with plaque.  These inflammations can lead to ruptures which can cause heart attack in minutes.