RecruitingBehavioural interventionSleep Duration and Cardiovascular HealthThis is a cross-sectional study with an optional intervention that will examine how extreme sleep durations relate to cardiovascular health, physical activity, and sleep quality by studying three groups of participants: short sleepers (≤ 6 hrs), long sleepers (≥ 9 hrs), and average duration sleepers (7-8 hrs). The optional intervention asks participants to maintain an 8-hour per night regular sleep schedule for one week.