Physical activity can prevent a heart attack because you're increasing your blood flow through your body. You're also making you cholesterol ratio between you "good and bad" cholesterol balance out. Example, if you have a high "bad cholesterol" (LDL level) and a high "good cholesterol" (HDL level), the exercising will help increase your HDL levels and lower your LDL cholesterol.
Also, a lot of people don't realize that the younger you are and have a heart attack, the LEAST likely you will survive. This is opposite of a normal idiopathy.
The younger we are, the less "added pathways" our veins/arteries have within our heart. Exercising can actually create these additional pathways within our heart to held reduce the risk of a heart attack and if someone does have a heart attack, they have addition pathways for blood to flow and less of the heart muscle will die.
