The right side of the image, which depicts a sleeping person, reinforces the importance of situational context in sleep physiology (94). The external environment is shown as a dawn-to-dusk transition, reinforcing the importance of day-night circadian context in sleep physiology (6). Health outcomes associated with sleep—cardiovascular health (23), metabolic health (31), immune health (38), mental health (39), behavioral health (24), and cognitive health (50)—are listed. On the left side of the image, the levels of the social-ecological model are depicted. Individual-level factors that influence sleep include age (58), genetics (105), sex and gender (69), beliefs (94), feelings and attitudes (94), race and ethnicity (78), and behaviors (94). These are embedded within social-level factors, which include neighborhood (88), work and occupation (84), family and home (101), culture (80), social networks (90), socioeconomics (76), and safety and security (89). These factors are further embedded within those at the societal level, such as such as technology (95), globalization (94), racism and discrimination (93), public policy (91), geography (92), the physical environment (94), and “24/7” society (83).