schwit1 sends word that a new study published in PLOS Medicine has examined how lifestyle risk factors can affect mortality rates, both alone and in combination with each other. Having a single major risk factor increased mortality rates slightly, but the study found that those who report multiple risk factors are significantly more likely to die early. While this includes obvious behavior like smoking and alcohol consumption, the findings also suggest prolonged sitting and unhealthy sleep patterns can strongly increase mortality rates when combined with each other, or with the obvious behaviors. "Some combinations were more deadly than others, the researchers found. Those who blended insufficient exercise with prolonged sitting were 2.42 times more likely to die during the study, and those who were also guilty of sleeping for too many hours were 4.23 times more likely die by the time the study ended. 'These findings suggest there is a "synergistic effect" among risk factors,' the study authors wrote."