Most of us have a fixed work and sleep schedule. The 'work-during-day' and 'sleep-at-night' cycle keeps our body and mind alert at the right time, without any external interference. However, globalization has given rise to many jobs that require employees to work in shifts. Various jobs that require night shifts include security guards, medical interns, nurses, bartenders, oil rig workers, gas station attendants, customer service, paramedics, and even IT workers. This creates a major problem for the body's internal clock, since the natural sleep-wake cycle is affected. Certain adjustments must be made to one's schedule in order to train the body for different shifts so that the resulting sleep deprivation doesn't lead to any serious disorder.