Yes, and the Zeo is a REAL sleep tracker in the sense that it uses EEG -- not accelerometers -- as sensors (where the latter actually don't measure anything tha

Yes, and the Zeo is a REAL sleep tracker in the sense that it uses EEG -- not accelerometers -- as sensors (where the latter actually don't measure anything that has to do with sleep, just a proxy that is somewhat correlated but also easily fooled). Remember, when you get a real lab sleep study done, the primary measurement of sleep is via the spectral powers of your brain waves via EEG -- these measurements represent your sleep stages, by definition.