The human circadian clock from health to economics.

In the course of evolution, health is prioritized for human well-being and economies. Epidemiological and experimental studies suggest that modern life habits, including eating habits, and living and working conditions, can deteriorate health through circadian misalignment. This has been most commonly observed with urban societies and working classes of non-standard working schedules (NSWSs), such as shift work, night work, and overtime work. Poor health conditions with NSWSs generate economic burden for the modern society. Therefore, we attempt to provide a systematic approach to understanding the relations among the circadian clock, health, and economics. To understand these connections, we review the mechanisms of the human circadian clock and how modern living conditions can misalign the circadian system and associated health consequences. We also emphasize the importance of health for the modern economy and the economic costs of health disorders associated with circadian disruption and NSWSs.