Nearly 15 million Americans do shift work, and the lack of sleep and sleep disruptions they face can have serious health implications. A study found that men who do shift work without napping during the day are 43 percent more likely to be diagnosed with cancer later and are twice as likely to die as a result. Sleep deprivation and the presence of light at night while working an overnight shift can inhibit the natural production of melatonin, a hormone that affects sleep cycles. The key for shift workers is consistency—stay on the same sleep schedule every day of the week. Learn more about the link between shift work and cancer.