More than half of Americans are concerned about their everyday stress levels, according to the American Psychological Association—and for good reason. Chronic stress can lead to serious health problems, including hypertension, stroke, heart disease, diabetes, and ulcers. But not all stress is equal, experts say. Stress that arises from facing obstacles while you’re working to make a positive difference is, in fact, good stress that can leave you happier and more fulfilled. Humans are genetically built to manage this kind of stress. Here, three experts tell how to discern when you’ve moved beyond healthy stress and how to get stress levels in check.  Stress may not be the only cause of these symptoms; consult a doctor to be sure.