> men in Japan who sleep less than six hours a night are 400-500% likelier to have a heart attack Seriously? People who sleep less might be at risk of all sort

> men in Japan who sleep less than six hours a night are 400-500% likelier to have a heart attack Seriously? People who sleep less might be at risk of all sorts of health problems, but not necessarily because they sleep less - people generally sleep less because they're doing [strenuous or destructive activity]. And it's much more likely that partying / working late into the night causes health problems, rather than solely the lack of sleep. Correlation ≠ causation