What is 'circadian dysrhythmia' and how does it affect air traffic controllers on shift work?

1. The disruption of the body's natural 24-hour sleep-wake cycle, causing sleepiness, reduced alertness, and slower reaction times
2. A cardiac arrhythmia caused by working near high-voltage radar consoles
3. A temporary speech impediment caused by talking rapidly on the radio
4. The synchronization of breathing cycles with radar sweeps