Why 2pm#
Everyone has an explanation. Almost everyone has the same one.
The received explanation, in one line#
The slump is real, and the answer offered for it is always lunch.
It is a good explanation. It is also wrong — and what replaces it is why this course can call the nap a need rather than a habit.
Two processes, not one#
| Process | What it does | On what clock |
|---|---|---|
| Sleep pressure | rises the longer you are awake | no clock — just time since waking |
| Circadian rhythm | oscillates, independent of pressure | roughly a 24-hour cycle |
What you feel at any moment is the two of them combined.
The afternoon trough#
The circadian rhythm has a second dip.
- smaller than the one at night
- roughly twelve hours away from it
- for most adults, early afternoon
“It’s the sandwich.”
Said with confidence, by someone who has never skipped the sandwich to check.
It is on the clock#
Not on the menu
The evidence that it isn’t lunch#
- skip the meal — the dip still arrives
- move the meal — the dip does not move with it
- food does affect alertness, but the effect is small
Real, and not what people are pointing at.
Chronotype#
The trough is not at the same hour for everyone.
Which is why a nap policy pinned to a single time of day helps some people and simply inconveniences the rest.
We do not get to solve that today. The design week does.
The institutional consequence#
If the dip is scheduled and predictable, then a workday built as though it isn’t is not neutral.
It is a design decision.
Someone made it.
Before next week#
Bring the trough estimate you wrote at the start of the course and never went back to revise.
Next time we stop asking what the body does and start asking who decided it was unreasonable.
Tell me it’s the sandwich#
The post-lunch dip is misnamed twice over: it is not caused by lunch, and for a good number of people it is not after lunch either.