Sleep & recovery
Measured at the source.
A sleep lab reads your brain. Your watch reads your pulse and makes an educated guess. Those are not the same thing, and the difference shows up most in deep sleep — the part that actually restores you.
Sleep & recovery
A sleep lab reads your brain. Your watch reads your pulse and makes an educated guess. Those are not the same thing, and the difference shows up most in deep sleep — the part that actually restores you.
What changes
Light, deep and REM read from the signal that defines them, plus eye movement and muscle tone from the same sensors. Wrist devices infer stages from heart rate and motion, and the place they struggle most is telling deep sleep from REM — which is exactly the distinction that matters for recovery.
Slow-wave activity should fall away across the night as sleep pressure dissipates. When that curve stays flat, sleep was unrefreshing even if the total hours look fine. It explains the nights where you slept eight hours and woke up hollow — and it is invisible without EEG.
A device on your head knows your head's orientation. Sleep position matters for snoring and for breathing, and it is something a wrist can never know.
Light at 02:40. A bedroom at 24°C. Noise from the street. The room sensor logs it, so “you slept badly” becomes a sentence with a cause attached.
Closed loop
During deep sleep your brain produces large, slow oscillations. Quiet bursts of sound, timed to the rising phase of those waves, have been shown in published research to increase slow-wave activity.
The timing has to come from your own brain, wave by wave, in real time. That makes it the one feature in this category that cannot be copied by a device on your wrist — it depends entirely on the measurement being good.
Reported effects are modest and differ between people, so rather than quote an average at you we would rather show you your own nights with the sound on and with it off, and let you decide.
No electrical current. Nothing applied to your skin but sound.
Every morning
Ninug is a wellness product. It does not diagnose or treat sleep disorders.
It is also where we are looking hardest for research partners — sleep labs and clinics willing to run us against expert-scored polysomnography.