[pedalpete]

Your devices are tracking sleep time, which makes about as much sense as measuring your diet based on how much time you spend chewing.

Time in deep sleep is not a direct marker of slow-wave delta power, which is just one of the measures of repair and glymphatic flush which occurs during deep sleep.

If slow-wave activity is slightly impaired, your brain can try to make up for that reduction by increasing time in deep sleep.

However, larger impairments mean your brain will struggle to stay in deep sleep.

This is why our work at https://affectablesleep.com focuses directly on enhancing the Neural Function of Sleep (and specifically deep sleep) rather than focusing on time.