The faster your heart rate drops after exercise, the lower your risk of dying of a heart attack, according to a 2005 study in the New England Journal of Medicine that followed 5,713 men for 23 years.
Subtract your heart rate at one minute after a workout from the maximum heart rate you reached during the workout. If the difference is more than 35 beats per minute, you're probably not at an increased risk.
Otherwise, check the numbers below to determine your risk of dying of a heart attack.
Percentage increase in risk of sudden death due to a heart attack: 110
Drop in heart rate one minute after exercise (measured in beats per minute): < 25
Percentage increase in risk of sudden death due to a heart attack: 30
Drop in heart rate one minute after exercise (measured in beats per minute): 25-30
Percentage increase in risk of sudden death due to a heart attack: 40
Source: Some facts noted after reading an article a while ago...