Shift work is a fundamental component of the US workforce and an integral part of the lifestyles of a large proportion of the population. More than 22 million Americans work on shifts as part of their work life. Emerging research suggests that shift workers are at higher risk for a range of metabolic disorders and diseases (eg, obesity, cardiovascular disease, peptic ulcers, gastrointestinal problems, abnormal blood glucose levels, and metabolic syndrome). Sleep disorders associated with shift work also pose a serious public health risk, as they can impair an individual's ability to perform effectively and may lead to occupational and traffic accidents.