Can negative emotions be considered the “canary in the coal mine,” an early warning sign of poor health to come? Individuals prone to distress appear to be more vulnerable to cardiovascular disease, and such predispositions may emerge early and persist over the life course. We will consider the evidence that negative emotions influence heart health and think about how early in the life course such effects could be set into motion. We will also discuss biological and behavioral mechanisms underlying this relationship, considering how these processes may operate across the life course.