Sleep medicine employs a range of tools, from advanced medical equipment to modern consumer devices, to analyze what happens during sleep. The main medical tool, polysomnography (a comprehensive overnight sleep study), uses sensors to track brain waves (through electroencephalography or EEG), eye movements, muscle activity, heart rhythm, breathing, and oxygen levels. While medical grade equipment remains the gold standard for diagnosing sleep disorders, consumer sleep technology like smartwatches and rings has evolved to offer insights into personal sleep patterns, though with certain limitations. These devices use sensors to track movement, heart rate, and sometimes oxygen levels, helping people better understand their sleep while acknowledging that they can’t replace professional medical evaluation.