Many people who are working odd shifts for their jobs experience sleep issues. They often lose one to four hours of sleep per night, and the condition can impact their mood and performance at work, and put them at risk for workplace accidents and drowsy driving. The most common type of shift work disorder is called a circadian rhythm sleep disorder (CRSD). This condition involves an irregular or non-synchronized sleep/wake cycle. It is usually associated with a shift schedule that is not aligned with the body’s natural sleep-wake rhythm, which is typically based on the sunlight’s signal.