The biopsychosocial model of challenge and threat (BPS) holds that during active goal pursuit, psychological processes reliably lead to specific patterns of cardiovascular responses. Because psychological experience during goal pursuit is not otherwise easily accessible, using cardiovascular responses to infer psychological states can provide valuable insight. In this context, challenge results from evaluating high resources and low demands, whereas threat results from evaluating low resources and high demands. Both challenge and threat lead the heart to beat faster and harder than during rest, but challenge results in dilation in arteries and more blood pumped, whereas threat results in constriction and less blood pumped. This article summarizes the BPS, presents recent research applications, and discusses remaining questions and future directions, including how research from other theoretical perspectives may clarify the nature of task engagement and how the BPS can inform the study of resilience to stressors.