By the end of the day, nearly 2,200 Americans will die of heart disease.  That's one person every 39 seconds.  Many people who are at high risk for a heart attack don't even know it.

Edith Donohue isn't taking any chances.  She lost her grandparents and mother to heart disease.  She is doing everything she can to keep her heart healthy.  "I do something every day.  Walk, I play tennis doubles, I'm a kayaker and I have a single kayak," says Donohue.

In matters of the heart, awareness is key.  So what do you know about your heart?  You know it pumps your blood, but how many times does it beat a day?  Is it 1,000, 10,000, 50,000 or 100,000 times?  The average heart beats 100,000 times a day.

What about heart disease?  True or false: Heart disease is a disease of the elderly?  The answer is false.  In fact, according to the American Heart Association, almost 150,000 Americans killed by cardiovascular disease each year are under the age of 65.  And, one out of every 20 below the age of 40 has heart disease.

What if you're healthy?  At what age should you start getting checked for cardiovascular disease?  The answer:  The American Heart Association recommends you begin assessing your risk at age 20.  Even young adults can develop cardiovascular disease as a result of their lifestyle. 

Finally, do you know your heart attack symptoms?  While severe chest pain can be felt by both men and women, women may have subtler symptoms like abdominal pain, back and jaw ache, fatigue, nausea and shortness of breath. 

MORE ONLINE: American Heart Association's heart attack risk assessment