Module 1 in 10 slides

Slides 4 min

You will be able to: See the whole module at a glance before you read it, and use the deck for a quick review later.

Swipe, use the arrow keys or the buttons. Come back to this deck before the quiz: it is the fastest review.

Your sleep, right now

Module 1 of Sleep, Decoded

This week you measure. Next week you experiment. The week after, you plan.

The one-line promise

By Sunday you will know how much sleep you need, what a short night costs you, and you will have 7 days of your own data.

7 hours or more

Sleep experts in the US agree that adults aged 18-60 should sleep 7 hours or more on a regular basis. The NHS puts it at 7 to 9 hours for most adults.

Teenagers need more: 8 to 10 hours.

Time in bed is not time asleep

17 hours awake

In a lab study, after 17 to 19 hours without sleep, people did as badly on some tests as they did with a blood alcohol level of 0.05%, the legal driving limit in Scotland.

Up at 6:00? That is 23:00 to 01:00.

The sneaky part

When people had 6 hours in bed a night for two weeks, their test results kept getting worse, but their own sense of sleepiness levelled off.

Feeling fine is not proof that you are fine.

Sleep debt

Sleep debt = the sleep you need minus the sleep you get, added up over the nights.

Need 7 h 30, get 6 h for 5 work nights: 7 h 30 of debt by Friday.

The weekend lie-in trap

In a lab study, two nights of sleeping in did not prevent the drop in insulin sensitivity caused by short work-week nights.

Sleep experts advise small nightly top-ups and a steady wake time instead of one big lie-in.

Regular beats heroic

In a study of about 61,000 UK adults wearing activity trackers, how regular their sleep timing was predicted their risk of dying early better than how long they slept.

Your anchor: one wake-up time, 7 days a week.

Your jobs this week

Set your anchor wake-up time.
Find your lights-out window with the calculator.
Fill in the sleep diary every morning for 7 days. No changes yet: just watch.

Sources for the facts in this deck are on the article pages that follow, and in full on the How this course was made page.

Next: why a short night costs more than you think