Sources: health-report-2026-07-20-to-2026-07-21.json (Apple Watch sleep stages, exported 06:49 on 07-21) + OSCAR_Greg_by_Day_2026-07-20_2026-07-21.csv (ResMed AirSense/AirFlow 11 via OSCAR). Matched by calendar date of sleep-session start (22:54 on 07-20).
Deep sleep = 8.3% (29.6 min) — a new all-time low, and the 5th consecutive night of decline (16.6% → 16.4% → 14.7% → 10.1% → 8.3%). This is the most important signal tonight: a full 8.3 percentage points below the prior floor (10.1% on Jul 19) and more than 10 pp below the 5-night average (13.2%). No prior matched night has had deep sleep below 10%.
Critical dissociation: AHI 0.94 and Leak 0.03 — the best CPAP night on record — yet sleep architecture is at its worst. Leak dropped 97% overnight (0.92 → 0.03 L/min) and AHI fell to the lowest value ever recorded for the user. RERA = 0. The machine ran at the lowest average pressure in weeks (7.14 cmH₂O). By every CPAP metric, this was an outstanding night. The continued deep sleep collapse despite that is a genuine anomaly and cannot be attributed to mask seal or respiratory events tonight.
Implication: the deep-sleep deficit appears to be lagging or decoupled from nightly CPAP performance. Three possibilities: (a) cumulative sleep architecture disruption from the prior leak-escalation period (5 nights of poor deep sleep can't be recovered in a single night); (b) a confounding factor unrelated to CPAP (stress, alcohol, inconsistent schedule, late exercise, etc.); (c) natural night-to-night variability now amplified by a small sample. This warrants monitoring over the next 3–5 nights to determine if deep sleep begins to recover now that leak is resolved.
Pressure average 7.14 cmH₂O — the lowest since the near-zero baseline readings in mid-June — reflects the machine running very efficiently at low event load. This is not a concern; it confirms the CPAP performed optimally.
| Metric | Value |
|---|---|
| Bedtime (session start) | 22:54 |
| Time in bed | 6.29 h (377.3 min) |
| Total sleep duration | 5.94 h (356.3 min) |
| Sleep efficiency (TST/TIB) | 94.4% |
| Awake time | 21.1 min |
| Core sleep | 4.20 h (251.9 min) — 70.7% |
| Deep sleep | 0.49 h (29.6 min) — 8.3% — new record low |
| REM sleep | 1.25 h (74.8 min) — 21.0% |
| CPAP usage | 6.38 h |
| AHI | 0.94 — best ever recorded |
| RDI | 0.94 |
| OA / H / CA / UA / RERA | 2 / 3 / 0 / 1 / 0 |
| Pressure avg | 7.14 cmH₂O (lowest in weeks) |
| Pressure 90th %ile | 9.92 cmH₂O |
| Leak avg | 0.03 L/min (near zero — resolved from 0.92 prior night) |
| Leak max | 7.2 L/min |
| Leak 90th %ile | 0 L/min |
| Date | AHI | RERA | Leak avg | Deep % | REM % | Awake (min) | Efficiency |
|---|---|---|---|---|---|---|---|
| 07-16 | 1.50 | 3 | 0.13 | 16.6% | 20.6% | 12.5 | 96.3% |
| 07-17 | 2.78 | 0 | 0.27 | 16.4% | 30.0% | 7.0 | 98.2% |
| 07-18 | 2.35 | 0 | 0.54 | 14.7% | 23.1% | 36.6 | 90.3% |
| 07-19 | 1.29 | 1 | 0.92 | 10.1% | 17.0% | 14.0 | 96.2% |
| 07-20 | 0.94 | 0 | 0.03 | 8.3% | 21.0% | 21.1 | 94.4% |
Trend: Deep sleep has declined for 5 straight nights (−8.3 pp total). Leak escalated from 7/16 to 7/19 then collapsed on 7/20. The fact that deep sleep fell further even as leak resolved breaks the simple leak→architecture hypothesis as a same-night driver.
Using the prior report's 9-night dataset plus tonight (split at leak ≤ 0.30 vs. > 0.30 L/min):
Adding 7/20 reshapes the picture. Tonight is the most extreme low-leak night in the dataset (0.03 L/min) but has by far the worst deep sleep of any low-leak night (8.3%). The group-level difference (15.1% vs 12.2%) still favors low-leak nights on average, but that advantage is now driven primarily by 7/11–7/17; 7/20 is a clear outlier that sits well below the high-leak group mean.
the user r (leak vs. deep%) across all 5 stage-matched nights from Jul 16–20: r = −0.17 — essentially no linear correlation. The declining deep sleep trend across this period is not explained by nightly leak levels alone.
Working interpretation: The leak escalation from 7/16–7/19 likely disrupted sleep architecture cumulatively. Even after the acute trigger resolved, the architecture deficit persists — typical of slow-wave sleep debt, which recovers gradually over multiple nights rather than rebounding in a single night.
| Metric | Tonight (07-20) | 7-day avg (07-14–07-20) | 30-day avg (06-22–07-20) |
|---|---|---|---|
| AHI | 0.94 | 2.15 | 2.76 |
| RDI | 0.94 | 2.40 | — |
| RERA | 0 | 1.57 | 1.28 |
| Pressure avg (cmH₂O) | 7.14 | 8.62 | 8.58† |
| Leak avg (L/min) | 0.03 | 0.35 | 1.02* |
| Usage hours | 6.38 | 6.34 | 6.48 |
| Deep sleep % | 8.3% | ~13.2%‡ | — |
| REM sleep % | 21.0% | ~22.3%‡ | — |
| Awake time (min) | 21.1 | ~18.2‡ | — |
*30-day leak elevated by Jun 24–27 and Jul 01 high-leak nights.
†30-day pressure computed from 28 non-zero-pressure nights (excludes Jun 15–22 zero readings).
‡Sleep-stage averages computed across 5 nights with stage data (Jul 16–20).
| Week | AHI avg | RERA avg | Leak avg | n |
|---|---|---|---|---|
| 06-22 to 06-28 | 2.84 | 0.86 | 1.98 | 7 |
| 06-29 to 07-05 | 3.24 | 1.29 | 1.41 | 7 |
| 07-06 to 07-12 | 3.00 | 1.14 | 0.43 | 7 |
| 07-13 to 07-19 | 2.22 | 2.00 | 0.42 | 7 |
| 07-14 to 07-20 (trailing 7d) | 2.15 | 1.57 | 0.35 | 7 |
AHI is at its lowest weekly average of the entire tracked period. RERA is declining from the 2.00 peak of last week. Leak 0.35 is the lowest weekly average since the zero-baseline period. Tonight's near-perfect CPAP metrics, if they hold, will push next week's averages down further.
The next 3–5 nights are the key test. If deep sleep recovers toward 12–16% over that window, it supports the cumulative-deficit interpretation and suggests no further intervention is needed beyond maintaining the mask seal fix. If deep sleep remains below 10% despite continued low leak and low AHI, that would argue for another contributing factor worth investigating (sleep timing, total nightly opportunity, lifestyle variables, or mask-related microarousals not captured in the CPAP event log).