Estimated annual GDP loss from workforce sleep deprivation through three channels: mortality (shorter lifespan), absenteeism (more sick days), and presenteeism (reduced on-the-job productivity). Hafner et al. (2017) estimate: US loses $411B/year (2.28% GDP), Japan $138B (2.92% GDP), UK $50B (1.86% GDP). Calculated via human capital approach.