Your night, as a story.

The night story

• Deep NREM 3
• REM
• Light NREM 1–2
• Awake

Your night is one timeline: sleep stages, with a lane underneath for stress, heart rate, HRV or breathing. Time in each stage sits beside its typical range, and your night vitals sit below: HRV, lowest heart rate, breathing rate, skin temperature against your normal, average night stress and wake-ups.

Stages come from the Loop’s own sleep staging. Keely has its own sleep detection for bands that don’t stage sleep, labelled as Keely’s estimate, but with the Loop the stages are the band’s. The night starts when you fell asleep: lying still in bed awake looks like sleep to a wrist’s movement, so Keely checks the first stretch against your heart rate, and starts the night once it reads asleep for 15 minutes running. While the Loop is still recording your night, Keely leaves it on the band until it’s finished.

Sleep need

Your need tonight has three parts:

1. Your base. It starts as your goal, 7 h 50 m unless you change it, anywhere from 5 to 11 hours. Then it adapts to what you sleep before good mornings: over six weeks, once there are enough, it moves toward the sleep that leaves you recovered, at most an hour from your goal and never below 7 hours or your goal, whichever is lower.
2. Debt. A quarter of what you’ve fallen short of your goal over the last 3 nights, up to an hour.
3. A hard day. 40 more minutes for every 100 % you went over yesterday’s Load target, up to 30 minutes. In your first weeks the target is still learning your usual day, so this part grows with the days your Loop has measured: a third of it after 3 days, most of it after two weeks.

For example: a base of 7 h 50 m and three nights of 7 h 20 m, 6 h 40 m and 7 h 50 m leave 1 h 40 m of shortfall, so debt adds 25 minutes. Yesterday’s Load was 250 against a target that topped out at 200, 25 % over, which adds 10 minutes. Tonight’s need is 8 h 25 m.

Up and about

Tap End sleep when you’re up, and Keely tells your Loop, reads your night from what it has handed over and shows it straight away; the Loop’s own staging still decides the night when it arrives. Once you’ve done that a few times, Keely learns how soon after you start moving you’re really up, and reads your night from then even if you forget.

Performance, and how sleep feeds Recovery

Performance is time asleep divided by need. It’s one of Recovery’s five inputs, worth 20 %, read against the night’s own need, without the debt: 85 % of it counts one step against you, and sleeping past it helps, but only a little. See how Recovery works.

Regularity

A regular schedule helps sleep, and in large studies it went with better health than sleep length alone did. Keely uses the Sleep Regularity Index: minute by minute over your last 14 days, how often you were in the same state, asleep or awake, as 24 hours later:

regularity = 200 × P − 100

P is the share of minutes that matched. 100 means the same every day; naps and a night split in two count, and minutes your Loop wasn’t on your wrist are left out rather than called awake. Seven nights at 23:00–07:00, one of them starting at 01:00, score 94. Above 87 reads as regular and under 72 as irregular, the cut-offs of a UK Biobank study of 72,269 people.

Once there are four weeks of nights, Keely also shows how much later you sleep on free days (social jetlag), and the midpoint of your free-day sleep with catch-up taken out, a pointer to your body clock that can sit 2 hours either way.

Tonight

Keely works backwards from when you usually wake:

lights out = usual wake − tonight’s need − 12 minutes

The 12 minutes are the time it usually takes to fall asleep.

With a usual wake of 06:45 and a need of 7 h 35 m, lights out is 22:58. You can turn on a bedtime reminder for it.

Frequently asked questions

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