A Level 1 Sleep study is used to help determine the cause of excessive daytime sleepiness and to diagnose various sleep disorders. A Level 1 study records your brainwaves, heartbeats, and breathing as you sleep. It also charts your eye movements, limb movements, and oxygen in your blood. Level 2 sleep study is conducted in your home. The device provided records your oxygen levels, heart rate, airflow, snoring, and other parameters while you are asleep. Level 3 refers to Sleep Apnea Screening with Oximetry, which measures blood oxygen levels; this test may also include measuring heart rate. Level 3 study is also used to test for Pediatric sleep disorders.