Sleep & CPAP dashboard v4

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Read me first. This is a data view of your own logs — Apple Watch sleep stages and OSCAR-parsed CPAP data — not medical advice. Reference ranges below are from public guidance (AASM, ResMed, National Sleep Foundation) for orientation only; changes to therapy should go through your provider.

Time window

from to

What the data is telling you Based on all data

A fresh read of your nightly telemetry, regenerated each morning from the full dataset — narrative below is written to reflect today's stats, not a snapshot from earlier.

Across 124 CPAP nights the trailing-30 window continues to run modestly better than the all-time baseline on the respiratory side: AHI median 1.65 vs 1.85 all-time (−10.5%), OA median 7 vs 8 (−12.5%), and CA median has collapsed to 0 from an all-time median of 1. Pressure is tracking essentially flat (P95 10.21 vs 10.22). The one axis that has drifted the other way is mask seal: leak P95 median is 3.6 L/min over the last 30 nights vs 2.4 all-time (+50%), and leak average is +56%, so even as events have eased the seal has loosened some.

The last seven nights carry a travel signature — two Eastern Time nights on 10-14/10-15 and a return to Central Time on 10-16 — that produced the sharpest REM swing in the dataset: 33.6% on 10-14, a window-floor 15.8% on 10-15, then a window-ceiling 36.5% rebound on 10-16. Last night (10-17) kept the rich-stage profile with REM 27.2% and Deep 15.9%, but the flow-limitation side pushed to its window ceiling: Min_Above_020 at 10.1 minutes is the single highest reading in the 26-night window, Min_Above_010 is 3rd-highest, and FL_P95 is tied for 2nd. Two of the last four nights now sit above AHI 2.5, with hypopneas (H=8) leading the composition rather than centrals.

The relationship worth tracking is a divergence: FL and AHI rose last night while the device's own pressure response did not — P_Avg 7.20 is the 2nd-lowest in the window. If that profile (elevated FL at a pressure the APAP isn't bumping up for) extends another two or three nights, it becomes a durable pattern rather than a one-off, and a conversation worth having with the sleep provider about raising the pressure floor.

Things to keep an eye on Based on trend analysis

Metrics that have drifted meaningfully from their baseline over the last 30 days, or single-night readings worth attention. Regenerated with the dashboard.

FL_P95 / Min_Above_020

FL_P95 0.13 and Min_Above_020 10.1 min on 10-17 (window ceiling)

A third consecutive night with FL_P95 > 0.11 confirms the 7-night elevated plateau as a durable regime. The next data point is key.

Pressure response divergence

P_Avg 7.20 on 10-17 (2nd-lowest in 26-night window) despite elevated FL and AHI

If elevated FL continues at depressed pressure for 2–3 more nights, consider whether the pressure floor needs to be raised. Normally rising FL triggers an APAP ramp-up; last night it did not.

Leak P95 (30d)

Trailing-30 median 3.6 L/min vs 2.4 all-time (+50%)

A 7-day stretch with Leak_Avg sustained above 2.0 L/min would suggest cushion or mask wear rather than one-off position effects.

Hypopneas (H count)

H=8 on 10-17 (2nd-highest in recent window, +100% vs 7d avg)

If H stays above 5 for the next 2 nights, the respiratory profile tilts toward hypopnea-dominant AHI, which pairs with the FL plateau — a joint signal worth noting.

AHI (recent trend)

4-night AHI path 2.86 → 1.42 → 1.86 → 2.65

Two of four over 2.5 is early for a regime label, but another >2.5 night would make it three of five. Both the recent >2.5 nights are OA/H-dominant.

Total sleep time

10-17 TIB 390.4 min (6h 30m) breaks a 4-night short-sleep run

Keeping TIB above 6 hours stabilizes the architecture and reduces REM-cycle truncation. Any dip back under 5h 30m would re-start the short-sleep count.

One night's detail

Total sleep

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vs. your typical night

Sleep efficiency

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Deep sleep

—

REM sleep

—

AHI

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RERAs

—

FL 95th percentile

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Leak 95th

—

Sleep architecture — this night vs. your typical night

CPAP event breakdown

Median AHI

— events/hr

Ref < 5 = "well-controlled"

Well controlled

Leak (95th pct, median)

— L/min

Ref < 24 (ResMed excessive line)

Excellent seal

Pressure (95th, median)

— cmH₂O

Auto-titrated within range

Stable

Nights of CPAP use

— nights

Median therapy hours per night

Highly compliant

Average sleep time

— hr

Ref 7–9 hr (NSF, adults)

Below target

Sleep efficiency

— %

Ref ≥ 85% = good

Excellent

Deep sleep (median)

— %

Ref ~13–23%

In range

REM sleep (median)

— %

Ref ~20–25%

In range

How your numbers sit against the reference ranges

Bars show green = target, amber = watch, red = concern. Diamond marks where you sit — thick tick is your median, thin caps are 10th / 90th percentile nights.

Bands are general educational references (AASM/ResMed/NSF) — not personalized targets from a clinician.

CPAP telemetry over time

Nightly values with a 7-day moving average. Threshold lines mark the "well-controlled" cutoffs.

Nightly AHI 7-day avg AHI = 5

Leak 95th (L/min) 7-day avg Excessive = 24

95th pressure Avg pressure

Obstructive apnea Hypopnea Central RERA

What those event types actually are (plain-English glossary) Based on all data

Every "AHI = 1.7" hides five different things the machine is counting. Here's what each one means, what usually causes it, and where a "normal on CPAP" range typically sits.

Obstructive Apnea (OA)

Your median per night: · Normal on CPAP: mostly < 10

Your throat physically closes off for ≥10 seconds. This is what CPAP was built to prevent — the pressurized air acts as an internal splint. If OA count creeps up, it usually means pressure is undersetting the collapse, position (back-sleeping), congestion, or weight change.

Hypopnea (H)

Your median per night: · Normal on CPAP: mostly < 5–10

A partial airway collapse — airflow drops ≥30% for ≥10 seconds, often with an O₂ dip or arousal. Softer cousin of OA, same causes. Machines count these separately because they respond to slightly different pressure adjustments.

Central Apnea (CA)

Your median per night: · Normal on CPAP: 0–5

Your brain briefly forgets to ask for a breath — no effort at all, no obstruction. A few per night is normal (especially around sleep-onset transitions). Persistently high CA on CPAP can be a sign of "treatment-emergent central apnea" and warrants a clinician conversation.

RERA

Your median per night: · Normal on CPAP: 0–5

Respiratory Effort Related Arousal — you didn't stop breathing, but airflow got restricted enough that your brain briefly woke you up to fix it. Doesn't move AHI, but adds to RDI (Respiratory Disturbance Index). RERAs are the "silent tax" that can fragment deep sleep without triggering the AHI alarm.

Unclassified Apnea (UA)

Your median per night: near-zero · Normal on CPAP: essentially 0

The machine detected an apnea but couldn't cleanly tag it as obstructive or central (usually because the flow-limit signal was ambiguous). Yours are essentially always zero, which is a healthy sign.

Flow Limit — the earliest sign of upper-airway resistance

Flow Limit measures how "squashed" the shape of each breath is (0 = perfect sine wave, 1 = flat-topped, straining). It shows up before a hypopnea or RERA gets counted, and in your data it's the upstream cause of the residual arousals AHI misses.

Weighted-avg FL (median night)

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Reference: 0.00 – 0.02 = "quiet"

Quiet

95th-percentile FL (median night)

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Reference: < 0.10 normal · 0.10–0.20 watch · > 0.20 meaningful

Watch band

Nights with 95th FL in "watch" band

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out of nights logged

FL ↔ RERA correlation

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Higher FL nights = more arousals — mechanistically consistent

Where each night's 95th-percentile Flow Limit falls

Each block is one night. Colored by which reference bracket the night's 95th-percentile FL sat in.

< 0.10 — normal, occasional squashed breaths 0.10 – 0.20 — watch, machine likely already responding > 0.20 — meaningful residual airway resistance

Flow Limit over time

Nightly 95th-percentile (blue) and weighted average (aqua). Coloured background bands are the reference brackets.

95th-pct FL Weighted-avg FL 0.20 line

How to read your Flow Limit numbers

Your median weighted-average FL is 0.02 — meaning most of your breaths are round and unrestricted. That's the "quiet airway on average" story. But your median 95th-percentile FL is 0.11, which puts % of your nights in the "worth watching" band (0.10–0.20), and one night crossed the 0.20 line. Read together: the tail of your breathing distribution — the roughly 1-in-20 breaths that are flow-limited — is what's driving your RERA count.

The mechanism, in one sentence: Flow Limit is the upstream metric, RERAs are the downstream event. In your data, nights with higher FL 95th-percentile are the same nights with more RERAs (r) — the strongest single correlation in your whole dataset. Which means: the levers listed in the RERA section (side-sleeping, EPR / pressure support, raising the pressure floor, controlling evening alcohol and congestion) all work by lowering FL first, and RERAs follow.

Sleep duration and bedtime — the largest lever in this dataset

Total sleep time (TST) is well below the 7-hour target on most nights. Bedtime is the strongest correlate.

Total sleep (hr) 7-day avg 7-hr target

Bedtime Wake time

Sleep architecture — stages by night

Minutes of deep, REM, and core sleep (per Apple Watch). Awake time in bed shown at top.

Awake Core Deep REM

What actually moves the needle on sleep quality

the user correlation (r) between each candidate driver and the outcome, across 58 nights with both CPAP and Watch data. Sign matters: negative bars = "more of this ⇒ less of the outcome". |r| < 0.2 is weak, 0.2–0.4 moderate, >0.4 strong.

Drivers of total sleep time (TST)

Drivers of deep-sleep minutes

Drivers of sleep efficiency

Drivers of REM minutes

Reading the tea leaves Regenerated daily

CA cluster closed with a zeroAfter a 3-night stretch of central apneas (10-14 CA=3, 10-15 CA=1, 10-16 CA=2), last night posted CA=0. The 7-day CA mean of 0.86 is still above the 30-day 0.37, but one more zero night pulls that back toward baseline and the uptick reads as a short cluster rather than a regime change.

Flow-limitation plateau is lastingFL_P95 over the last seven nights: 0.09, 0.14, 0.08, 0.12, 0.13, 0.09, 0.13 — only two of seven are at or below the 30-day baseline of 0.10. The initial 'episodic' framing has aged out; this looks like a sustained plateau. Last night's Min_Above_020 of 10.1 minutes is the full 26-night window maximum.

REM rebounded cleanly after the travel floorThe 10-15 travel short-night produced the window's lowest REM% (15.8%); 10-16 produced its highest (36.5%). Last night (27.2%) settled above the 30-day baseline, suggesting REM homeostasis has reset after the two Eastern Time nights.

Mask seal has drifted up on the 30-dayLeak P95 median is +50% over the last 30 nights vs all-time, leak average +56%. The last four CPAP-only nights have oscillated between a near-zero floor and mid-range 1.8 L/min, so this reads as position/cushion-seat dynamics rather than hardware wear, but worth tracking if any 7-day run stays above 3 L/min average.

Rich-stage architecture despite respiratory noiseLast night Deep + REM = 43% of sleep, well above the 30-day baseline near 38%. Even on a window-ceiling FL night, the architecture stayed strong — the population-level correlation between FL_P95 and deep sleep remains weak at −0.16, which this night underlines.

A closer look at your RERAs Based on all data

You're averaging RERAs per night (max ). Well within a normal range — but they're worth understanding because they don't show up in AHI.

What a RERA actually is

Airflow narrows enough that your breathing muscles have to work harder for ≥ 10 seconds, and your brain briefly wakes you up to open the airway. It's not counted as an apnea (you never fully stopped breathing) and it's not a hypopnea (airflow didn't drop far enough). That's the whole reason clinicians report RDI = AHI + RERAs — RERAs are the events AHI misses.

Why they matter for deep sleep

Every arousal — even ones so brief you don't remember them — bumps you toward lighter stages. Deep (N3) sleep is fragile: a handful of arousals per hour is enough to keep the brain from staying long enough to consolidate a deep-sleep bout. This is why people can have "clinically great" AHI but still wake feeling unrefreshed — the RERAs (and their upstream cousin, flow limitation) are quietly nibbling at architecture.

Levers that typically reduce them

Side-sleeping — most RERAs happen supine; a positional trainer or wedge pillow often halves them.
EPR / pressure support — a small increase in exhale relief widens the airway on the "vulnerable" phase of the breath.
Raising the pressure floor — auto-CPAP that's allowed to drop to 4 often finds itself chasing flow limits back up; a floor of ~7–8 is common.
Congestion control — allergies, alcohol, and evening dairy raise upper-airway resistance measurably.
Late-evening alcohol — even one drink relaxes airway muscles for hours and reliably raises RERA counts.

In your data, RERAs correlate weakly and negatively with deep-sleep minutes (r ≈ −0.19) — small effect, but in the direction the theory predicts. More striking: RERAs correlate strongly with Flow Limit 95th-percentile (r ≈ +0.39) — the strongest single correlation in your whole dataset. That's the mechanism confirmed in your own numbers: flow-limited breathing → arousals. See the Flow Limit section above for what to do with that.

Places to look that this data suggests

Framed as experiments to run, not prescriptions — each one you can prove or disprove with more of the same data.

Test the "earlier bedtime" hypothesis explicitly

Bedtime → TST is the strongest correlation in your data (r = −0.29). Your 90th-percentile bedtime is 00:06. Force a two-week block of "in bed, lights out, phone across the room by 22:15" and measure the delta in TST and next-day rating. Even if your body naturally wakes at 6:00, you'd gain a full hour of sleep opportunity.

Log a subjective 1–10 "feel" score every morning

The data can't tell you which nights felt best — so it can't rank drivers by that feeling. Add a one-tap morning score for 30 days and this same analysis becomes far more powerful: it will show whether feeling refreshed tracks with TST, deep sleep, REM, bedtime, or something outside CPAP (alcohol, meals, workouts).

Watch the deep-sleep vs. average-pressure relationship

Nights with higher average pressure show slightly less deep sleep (r ≈ −0.21). The effect is small and the ranges are still normal, but if a clinician has room to tighten your auto pressure range (e.g., lower the max a touch, or use EPR), it's the one setting-side lever the data hints at. Don't self-adjust — bring the chart and let them decide.

Add the things CPAP can't see

Alcohol timing, last meal, caffeine cutoff, exercise time-of-day, room temperature, evening screen brightness — all are known to affect deep sleep and REM independently of CPAP. Log two or three of these for 30 days and you'll have new columns for this same driver chart to rank.

Don't over-index on residual AHI events

Your residual events show essentially no correlation with sleep quality in this window (|r| < 0.05 for TST, efficiency, deep, and REM). Squeezing AHI from 1.7 → 1.0 is unlikely to move how you feel. The signal to chase is length and consistency, not "even lower AHI".