I can never understand the point in articles like this. Association is not causation. Perhaps people who are prone to heart disease, strokes, and other ill health also have the symptoms of emotional problems such as isolation as one of the accompanying symptoms. But that all depends on the person defining isolation. Some, as myself, are introverts and like to be alone to recharge. Being around people all day, joking, even being popular Mr or Mrs "Sociable" and well liked, outgoing leader type might make more cortisol stress on such a person if this popular person is an introvert and does not isolate themselves once in awhile. Some need more time alone, dare I say isolate themselves more to keep healthier? I'm an INTJ personality type. Look that up and see if what I say in my case doesn't make sense.