What time should I go to bed if I wake up at 5:00 pm?

For a 5:00 pm alarm the day is your night. Five cycles start at 9:15 am; the minimum four start at 10:45 am.

Why three times and not one

The middle option, 9:15 am, is five cycles and 7 h 30 min of actual sleep; 7:45 am is six cycles and 9 h. Both sit inside the adult range. The 10:45 am option is 6 h: enough to get through the day, not enough to do it twice.

Each cycle runs light sleep, deep sleep, then REM. Ninety minutes is the average; the real figure drifts between 70 and 120 minutes, and the first cycle of the night is usually the shortest.

Walk through the night from a 9:15 am lights-out: asleep by about 9:30 am, into the first stretch of deep sleep around 9:50 am, first REM period near 10:45 am, the halfway point of the night at 1:15 pm, and the longest REM period of the night starting around 4:25 pm — which is what a 5:00 pm alarm at the end of cycle 5 lets you finish.

All bedtimes for a 5:00 pm alarm

Formula: bedtime = wake time − (cycles × 90 min) − 15 min · adult range from the NSF 2015 panel and the AASM/SRS 2015 consensus · methodology

5:00 pm: sleeping later after the shift, on purpose

A 5:00 pm alarm suits night workers who do not go straight to bed. Finish at 7:00 am, take the children to school or sit down to a real breakfast, and the five-cycle bedtime of 9:15 am is still ahead of you; if the morning runs long, 10:45 am gives four cycles. It also fits an 8 pm to 8 am rota, where 9:15 am is the first bedtime you can reach at all.

The trade is at the other end. Waking at 5:00 pm leaves two hours before a 7 pm start and six before an 11 pm start. Two hours is enough to eat and to clear the grogginess that follows a long sleep, which the sleep-inertia research puts at up to half an hour, but not much more. In exchange you arrive fresher: by 7 am you will have been awake 14 hours, against 17 for someone who got up at 2:00 pm. Sleepiness on a night shift peaks toward the end of the night, so hours trimmed from that end are the ones that count. For a 9:15 am bedtime the last coffee is 3:15 am. The six-cycle option, 7:45 am, only works on a night you finish early or on a day off, when it is worth taking.

Every alarm in the 5 pm hour

Lights-out times for each alarm · last coffee = six hours before the five-cycle bedtime (Drake 2013) · full grid on the open data page

If you can't fall asleep by 9:15 am

Build in the fifteen minutes honestly: lights out at 9:15 am means phone down at 9:15 am, not "in bed, scrolling". If sleep has not come by 9:35 am, the guidance from sleep medicine is to leave the bed, do something dull in dim light, and return when sleepy — the next clean boundary is 10:45 am.

Try a different time