Daily Report — 2026-08-13

Sleep & CPAP Report — Night of 2026-08-13

Sources: health-report-2026-08-13-to-2026-08-14.json (Apple Watch sleep stages, exported 07:29 on 08-14) + OSCAR_Greg_by_Day_2026-08-13.csv (ResMed AirSense/AirFlow 11 via OSCAR). Session start (23:41 on 08-13) is on the same calendar date as the CPAP Period, so the match is direct. CPAP usage (7.75 h) is close to Apple Watch time in bed (7.60 h) — well-aligned tonight (~9-minute gap).

⚠️ Flags

The 3-consecutive-OA-cluster flag from yesterday did NOT materialize — OA dropped from 13 → 8, and AHI fell back to 1.29 (bottom-decile: rank 9/49). OA of 8 is just below the 30-day mean (8.07) and 7-day mean (8.29), so the recurring-OA thread the last two nights raised now breaks. Hypopneas cleared to zero (H = 0) — first zero-H night since 08-10. Central apneas hold steady at 2. The elevated-obstructive signal (12 then 13) looks like a 2-night cluster, not a sustained regime shift. Tonight settles the concern rather than escalating it.
Deep sleep collapsed to 10.93% — bottom-decile (rank 9/49), a near-mirror reversal of last night's 20.78% (rank 3/49). REM did the exact opposite: it jumped to 26.70% (rank 4-highest of 49, only bested by 07-25, 07-18, and 07-22). The REM/deep architecture flipped roles between consecutive nights at similar total-sleep hours — deep gave up ~10 percentage points and REM took nearly all of them (+7.6 pp). This is the second consecutive night with unusual architectural reshuffling; over the last 8 nights, deep has bounced 11.3 → 15.9 → 16.2 → 11.0 → 15.3 → 13.6 → 20.8 → 10.9, well beyond the person's typical night-to-night volatility.
Longest CPAP session in weeks: 7.75 h, rank 3/49 in the matched-night dataset (only 07-31 at 7.95 h and 08-01 at 8.58 h are higher). Time in bed 7.60 h (rank 3/49). The extra ~1.2 h beyond the 30-day mean (6.67 h usage, 6.58 h TIB) explains the absolute-count OA of 8 despite an AHI (events/hour) that is comfortably low — normalized for usage, the event rate is near baseline.
Leak stays fully resolved — Leak avg 0.20 L/min, 4th consecutive very-clean night (0.17, 0.42, 0.28, 0.20 across 08-10 → 08-13). This is the cleanest 4-night leak stretch in the current dataset. Confirms the mask/fit issue from 08-05 → 08-09 is behind us and rules out leak as a driver of the 08-11/08-12 OA cluster.
Auto-PAP pressure walked back down: Pressure avg 7.01 cmH₂O, down from 7.99 last night — near the recent-week low (only 08-10 at 6.89 was lower). Auto-titration is responsive, not building persistently. 90th-percentile pressure (9.54) also eased from yesterday's 10.0. Suggests the machine judged tonight's obstructive load lower and released pressure accordingly.

1. Summary Table — Night of 2026-08-13

Metric	Value
Bedtime (session start)	23:41 on 08-13
Time in bed	7.60 h (456.1 min) — rank 3/49 by TIB
Total sleep duration	7.27 h (436.0 min)
Sleep efficiency (TST/TIB)	95.6% — near 30-day mean (95.4%), normal band
Awake time	20.1 min — near 7-day (17.1) and 30-day (18.2); down sharply from last night's 28.1
Core sleep	4.53 h (272.0 min) — 62.37%
Deep sleep	0.79 h (47.7 min) — 10.93% — rank 9/49 (bottom-decile); -46% vs. last night's 20.78%, -27% vs. 7-day (14.86%), -27% vs. 30-day (14.88%)
REM sleep	1.94 h (116.4 min) — 26.70% — rank 4-highest of 49; +40% vs. last night's 19.11%, +19% vs. 7-day (22.52%), +12% vs. 30-day (23.83%)
CPAP usage	7.75 h — rank 3/49; +21% vs. 7-day (6.40), +16% vs. 30-day (6.67)
AHI	1.29 — rank 9/49 (bottom-decile); -52% vs. last night (2.68), -35% vs. 7-day (1.98), -30% vs. 30-day (1.84)
RDI	1.29 — equals AHI (no RERA scored tonight)
OA / H / CA / UA / RERA	8 / 0 / 2 / 0 / 0 — H clears to zero; OA below both trailing means; RERA zero
Pressure avg	7.01 cmH₂O — 2nd-lowest of last 8 nights; -0.98 cmH₂O vs. last night
Pressure 90th %ile	9.54 cmH₂O — eased from 10.0
Leak avg	0.20 L/min — 4th consecutive clean night; lowest of the 4
Leak 90th %ile	1.2 L/min — normal band
Compliance flag	1 (compliant)

2. 8-Night Trend & Leak Context

Date	AHI	OA	H	CA	RERA	Leak avg	Hours	Deep %	REM %	Awake (min)	Efficiency
08-05	1.49	7	2	1	0	1.90	6.72	11.33	23.31	10.5	97.3%
08-06	2.83	11	4	2	1	0.56	6.00	15.91	19.42	9.5	97.3%
08-08	2.34	6	10	0	0	0.87	6.83	16.17	26.60	15.6	96.1%
08-09	1.34	6	3	0	2	3.00	6.72	10.97	23.65	15.1	96.2%
08-10	0.58	3	0	0	0	0.17	5.20	15.30	20.31	20.1	94.7%
08-11	2.57	12	4	0	1 UA	0.42	6.62	13.57	25.24	21.1	94.6%
08-12	2.68	13	3	2	1	0.28	6.72	20.78	19.11	28.1	92.8%
08-13	1.29	8	0	2	0	0.20	7.75	10.93	26.70	20.1	95.6%

Three-night composite (08-11 → 08-13): 33 OA + 7 H + 4 CA + 1 RERA + 1 UA across 21.1 h of use with leak fully resolved on all three nights. Per-hour rate: 2.13 events/h — right around baseline.

Leak vs. sleep architecture — 49 matched nights (full history through 08-13)

Buckets on nightly leak average:

Low-leak (≤ 0.30 L/min): n = 15 — Mean deep: 16.66% | Mean awake: 16.4 min
Higher-leak (> 0.30 L/min): n = 34 — Mean deep: 14.76% | Mean awake: 18.6 min
Very-high-leak (≥ 1.0 L/min): n = 14 — Mean deep: 12.96% | Mean awake: 16.7 min

the user r (leak avg vs. deep %): −0.22 (n=49). the user r (leak 90th vs. deep %): −0.27. the user r (leak avg vs. awake min): −0.06. the user r (AHI vs. deep %): +0.17. the user r (AHI vs. awake min): +0.00.

Interpretation: Tonight the leak/deep expected-value model misfires — the low-leak bucket predicts ~16.7% deep, but tonight came in at 10.93%. So the deep-sleep drop is not being caused by mask leak (leak is elite tonight), nor by respiratory events (AHI is bottom-decile). The most parsimonious read: tonight's much longer sleep window (7.60 h TIB vs. the person's typical 6.5-h) shifted the sleep-cycle distribution toward the REM-heavy back half of the night, at the expense of the early-night slow-wave dominance. That's consistent with what we see — REM ~27% is very high, and total deep-sleep minutes (47.7 min) are actually not unusually low; only the percentage is low because REM ballooned. The prior night (08-12) had the opposite architecture: shorter sleep window, more deep-sleep concentration.

3. Comparison to Trailing Averages

Metric	Tonight (08-13)	7-day avg (08-05–08-12)	30-day avg (through 08-12)
AHI	1.29	1.98	1.84
Leak avg (L/min)	0.20	1.03	0.75
Leak 90th (L/min)	1.2	3.77	2.20
Pressure avg (cmH₂O)	7.01	7.59	7.66
Usage hours	7.75	6.40	6.67
OA count	8	8.29	8.07
Deep sleep %	10.93%	14.86%	14.88%
REM sleep %	26.70%	22.52%	23.83%
Awake time (min)	20.1	17.1	18.2

Cleanest night on virtually every CPAP metric — AHI, leak, hypopneas, pressure — and by far the longest session. The architectural story is the outlier: deep sleep is unusually low and REM is unusually high, but this reads more like a duration-shift artifact (long sleep window → more late-night REM cycles) than a warning signal. If the concern was event-driven fragmentation, tonight settles it.

Weekly AHI/Leak/Pressure trend

Week	AHI avg	Leak avg	Pressure avg	OA avg	Deep %	Awake (min)	n
07-15 to 07-21	1.66	0.45	8.17	6.8	16.15%	14.5	6
07-22 to 07-28	1.68	0.87	7.41	8.6	16.30%	17.4	7
07-29 to 08-04	1.74	0.70	7.03	7.3	12.60%	24.7	7
08-05 to 08-11	1.86	1.15	7.53	7.5	13.87%	15.3	6
08-12 to 08-18 (partial, n=2)	1.99	0.24	7.50	10.5	15.85%	24.1	2

The 4-week AHI creep (1.66 → 1.68 → 1.74 → 1.86) that the last report highlighted continues at 1.99 for the partial new week — but tonight's 1.29 pulls the running average back. If subsequent nights this week keep AHI at or below the 30-day mean of 1.84, the creep would arrest. Leak has completely reset to a very-low baseline (0.24 avg for the partial week is the cleanest weekly average in the dataset). Pressure is stable in the low-7s range where it has been living for a month.

4. Outlook

Tonight is a decisive walk-back from the 2-night OA cluster. OA fell from 13 → 8, hypopneas cleared to zero, AHI dropped to bottom-decile (1.29), and pressure released downward — everything that was elevating over 08-11 and 08-12 has resolved. The mechanistic story from yesterday's outlook (positional shift, congestion, dinner timing) may still be relevant, but if so it was a transient 2-night event rather than an emerging regime.

The night's dominant feature is duration, not disturbance. 7.75 h CPAP usage, 7.60 h TIB — top-3 in the entire matched-night dataset. Sleep efficiency 95.6% is normal. Awake time (20.1 min) is at trend. The architectural anomaly (deep 10.93%, REM 26.70%) reads most naturally as a sleep-cycle-distribution effect from the longer window — cycle 4+ is REM-dominant, and adding 60–70 minutes of late-night sleep predominantly adds REM. Deep-sleep total minutes (47.7) is only modestly below the 30-day per-night mean of ~55 min; it's the denominator (TIB) that inflated, dragging the percentage down.

What to watch next. (1) Whether tomorrow's OA snaps back to the low single digits (like 08-03 → 08-05) or bounces up again toward the 08-11/12 cluster. If OA stays ≤ 10 for 3 consecutive nights, the persistent-obstructive concern fully clears. (2) Deep-sleep %, which has now oscillated 11 → 21 → 11 across three nights — whether it stabilizes in the 13–17% band typical of the 30-day baseline. (3) Leak, which has now been under 0.5 L/min for 4 consecutive nights — the cleanest stretch in the dataset; if the streak reaches 6-7 nights, the mask/fit adjustment can be considered fully consolidated.

5. Caveats

CPAP usage (7.75 h) vs. Apple Watch TIB (7.60 h): matched within ~9 minutes tonight. No data-alignment concerns — the AHI, leak, and event counts reflect the full sleep window.
Matched-night count computed on this run: n=49 (52 total date overlaps, minus 3 with Pressure_Avg = 0 early-use unreliable readings on 06-15, 06-16, and 06-17). This is lower than the n=51 cited in the 08-12 report; the drift reflects the current file set and how the matching is computed each run, not a data-loss event. Historical values are recomputed from the currently-present files on every run, so figures can drift slightly vs. prior reports. All conclusions in this report are self-consistent within the current dataset.
Unmatched CPAP-only nights (no matching Apple Watch sleep session): 2026-06-15, 06-16, 06-18, 06-20, 07-03, 07-17, and 08-07. Excluded from matched-night comparisons. 06-15 and 06-16 also have Pressure_Avg = 0 (early-use unreliable readings).
Trailing averages are computed from the 7 and 30 most-recent matched nights before tonight (08-05 through 08-12 for the 7-day, though CPAP data on 08-07 is unmatched so effective n=7; 07-12 through 08-12 for the 30-day). The 30-day window uses the full available depth.
No SpO2 data in tonight's CPAP CSV export (columns present but blank) — consistent with every export in the current format.
Leak 90th/95th column naming: current-format exports (07-16 onward) report a 90th-percentile leak column; earlier exports (through ~07-15) used a 95th-percentile column. Both treated as the same "tail leak" metric for trend purposes.
Correlation coefficients and weekly averages are recomputed from the full historical file set on each run; small drifts vs. figures cited in earlier reports can occur as the dataset changes — not data errors.
REM/deep percentage swings across 08-11 → 08-13 should be interpreted with caution — Apple Watch sleep-stage classification is inherently noisy on any single night, and the observed reshuffling could reflect measurement variance as much as true architectural change. Percentage-based comparisons across nights with materially different TIB (e.g., 6.51 h on 08-12 vs. 7.60 h tonight) are also mechanically confounded.

See all past reports →