Personal anecdote. Last month my japanese friend in his late 30's collapsed from a stroke. He is a freelance (!) Web developer I collaborated with and I didn't know that before the accident but he used to work overnight without any sleep. Given his chain-smoking, drinking hectoliters of coffee and a sedentary lifestyle it's hard to miss the causes but still I wonder if just getting sleep could have prevented it to some degree. Now after 3 weeks of induced coma he's slowly regaining consciousness, though how much he will be able to is still unknown.