First shift or day shift is generally between the hours of 6 a.m.and 6 p.m. Second shift or afternoon shift is between 3 p.m. and 11 p.m. Third shift is between 11 p.m. and 6 a.m. Hours vary by company, but most shifts fit into these time frames.
More than 20 million workers in the United States perform shift work. Healthcare and manufacturing are two predominant industries that operate in shifts. Most companies pay premiums to workers who work either second or third shifts.
Shift work?particularly third shift work?is known to cause sleep problems. The issue is prevalent when workers rotate between different shifts. It makes it difficult to adopt a normal sleeping routine.