The body that looks perfectly recovered

Partly Overnight recovery, and the parasympathetic swing

What the guide says Body battery should refill overnight; failure to recharge signals deficit (D2). But she also names the 'parasympathetic swing' (B4/D5): after big exertion the watch can read suspiciously HIGH recovery/HRV, 'looks like good recovery', and a crash follows anyway.

How usable is it, day to day? Held up partly

The morning body-battery reading catches ~8 of 10 crash lead-ups but fires on ~7 of 10 ordinary days. When it fires, a crash follows roughly 1 time in 45. The variability anchor (HA07d) is the half that held up.

Catches: 77%; of crash lead-ups it fired on (sensitivity)
Stays quiet: 27%; of ordinary days it correctly stayed quiet (specificity)
When it fires: 2.2%; of the days it fires are followed by a crash (precision)
Lift: 1.05×; × more likely than knowing nothing

These describe how the signal behaves in daily life, framed against how rare crashes are, not whether the pattern is real. That verdict is the badge above; a usable-looking number doesn't make a signal that didn't hold real. Tier C (worth watching at best), and with only 29 crashes the margins are wide.

Where this one stands

Sometimes the night looks perfect and the crash comes anyway, the strangest, most personal thread in the data. One reading of it held up across the whole record; the body-battery number a normal user would trust did not.

The shape, across the four years:

the week before a crash (pooled) an ordinary day (range)

This signal's pooled path across 26 crashes (the bold line, with its spread) against the ordinary-day range (the grey band), by day before the crash. It reads the crash, not its approach: through the week before, the crash line sits inside the ordinary-day range, and drops below it only at day 0, the crash itself. An honest negative here (+4.1 pp, not supported). Bands are the day-to-day spread across the crashes (wide at 26); 0 is my own normal.

The week before a crash for The body that looks perfectly recovered: this signal's pooled mean vs an ordinary day's, per day, in standard deviations from my own normal (0). Bands (not shown here) are the day-to-day spread across 26 crashes.
Day	Crash week (mean)	Ordinary day (mean)
day -6	0.2	-0.2
day -5	-0.0	-0.3
day -4	-0.1	-0.2
day -3	-0.1	-0.1
day -2	-0.1	-0.2
day -1	-0.3	-0.1
the crash (0)	-0.9	-0.2

Partly, and the split is the finding. This pattern has two readings of one overnight state. The one most people would actually look at, a morning body battery that reads high, a night that looks perfectly recovered (HA10), did not separate crashes from ordinary days: it fired on ~8 of 10 crash lead-ups but also ~7 of 10 ordinary days. But the deeper reading, the collapse in night-to-night variability (HA07d), held up across the whole record (+19.7 pp, p=0.029), the same signal that carries 'the HRV signal we had to improvise', and it stays standing even after the medication is modelled out. So the state Wiggers names is real and detectable in my body; it just doesn't show through the reassuring number on the watch face. The watch is structurally poor at showing this state as unhealthy.

The numbers, for the record Anchor HA07d single-pool SUPPORTED (+19.7 pp, p=0.029; below the stricter cluster-corrected line at n=29; net of citalopram ~18.7 pp, still standing). Body-battery reading HA10 single-pool NOT-SUPPORTED (sensitivity ~77%, specificity ~27%; PPV ~2.2%, lift ~1.05x, Tier C).

The curve above is the real pooled shape; the fuller write-up (how it was tested, and what it means) is coming as this finding’s page is built out. For now, the shape, the status, and the working note are the honest summary.