Life expectancy and chronic disease rates both rose dramatically in the United States during the first third of the twentieth century. As a result of this concurrence, Americans in this era increasingly thought about things they could do to extend their own lives, especially eating less, exercising more, and limiting stress, all factors thought to reduce chronic disease. New recognition of the correlation between daily physical habits and long lives made longevity look like a sign of virtue. At the same time, amidst discussions about the relationship between individual longevity and national vitality, this correlation also contributed to Americans' moralization of diet, exercise, and emotional self-control.