Shift work bends the whole week
Six groups, six kinds of night. New parents wake most, night-shift workers sleep least, retirees sleep longest but lightest.
Six kinds of night
New parents slept 5h 57m and woke four times on a typical night. Night-shift workers slept 5h 26m. Founders 6h 08m, students 6h 44m, office workers 6h 50m and retirees 7h 23m, with the lightest sleep of all.
The late shift tax
Workers who rotated between day and night shifts slept 48 minutes less than those on fixed nights. The rotation, not the night, did the damage.
Founders and the 01:00 email
Founders were the only group whose weekday median bedtime fell after midnight. Two in five wrote work in their morning diary as the thing that kept them up.
What employers changed
Two partner employers moved rota changes to a fixed weekly day and banned internal email after 21:00 for a month. Sleep in those teams rose by a median 19 minutes.
The chart
Hours asleep on an average night; dots under the 7-hour line in cobalt.
Key findings
Three numbers to take away.
New parents woke four times on a typical night.
Rotating shifts cost 48 minutes compared with fixed nights.
An evening email ban added 19 minutes.
Sleeper diaries
