70% of 84 hunter-gatherers studied in 2013 slept less than 7 hours per day, with 46% sleeping less than 6 hours.
The study in question also found that the hunter gatherers spent 8-9 hours in bed each night. Sleep duration was measured using those Fitbit trackers that always tell you that you only slept four hours when you’re sure you slept about eight hours. If you move around in your sleep then the tracker assumes that you are awake.
This is an important point. When discussing sleep we have to both look at sleep as measured by devices (that do notice awake times during the night that aren’t remembered) and at time in bed.
It’s plausible that 7 hours of sleep are good for the average person while 8 hours in bed are necessary to achieve that for the average person.
The range the study gave for time in bed was actually 6.9–8.5 hours (not 8-9). But it’s a good point that subjective sleep duration reports significantly overestimate actigraph measurements.
The study in question also found that the hunter gatherers spent 8-9 hours in bed each night. Sleep duration was measured using those Fitbit trackers that always tell you that you only slept four hours when you’re sure you slept about eight hours. If you move around in your sleep then the tracker assumes that you are awake.
This is an important point. When discussing sleep we have to both look at sleep as measured by devices (that do notice awake times during the night that aren’t remembered) and at time in bed.
It’s plausible that 7 hours of sleep are good for the average person while 8 hours in bed are necessary to achieve that for the average person.
The range the study gave for time in bed was actually 6.9–8.5 hours (not 8-9). But it’s a good point that subjective sleep duration reports significantly overestimate actigraph measurements.
For what it’s worth, in my experience there is a wide delta in accuracy between bad fitbit-style sleep trackerse and good fiftbit-style trackers.
I do not know if this study used good or bad devices.