Are your sleep habits aging you prematurely?

When someone who is fairly young who appears to be healthy suddenly has a heart attack, the first question is "How did that happen?"  It could happen to any of us. We might be doing all the right things - eating a balanced diet, excercizing, drinking plenty of water. And we might be slim and trim. But we could be heading down a path of early aging and sudden death because of one thing we're robbing our bodies of - sleep. What are the long range effects of a hectic lifestyle of only three or four hours of sleep per night? What are the signs that you may be aging prematurely because of lack of sleep? Can you reverse the damage you may have done to your body? How?