Sleep: what to log and what good looks like

What Grepiac captures

The WellnessLog model has two sleep fields:

sleep_hours (decimal, e.g. 7.5): hours slept last night.
sleep_quality (1 to 10): subjective quality, 1 = terrible, 10 = perfect.

Both are optional, but having both produces a clearer signal than either alone.

Why two fields

Hours alone misses the case where you were in bed 8 hours but slept poorly. Quality alone misses the case where you slept great for 5 hours but were short. Together:

Good hours + good quality: rested.
Good hours + low quality: probably stressed, or woke up several times.
Low hours + good quality: short but deep; OK occasionally, problematic if recurring.
Low hours + low quality: red flag, especially across multiple days.

What "good" looks like for endurance athletes

Hours: most athletes need 7.5 to 9 hours in active training blocks; less is possible in light weeks. Below 6.5 consistently impairs adaptation.
Quality: 7 to 9 most nights. Anything below 5 for multiple nights is a signal.
Variability: weekly average matters more than any single night.

Grepiac does not prescribe a per-athlete sleep target. Athletes vary; what stays constant is whether their own baseline holds.

The concerning trigger

Logging sleep_hours under 5 fires a concerning flag (see Concerning flags explained). The flag is on the entry, not a multi-day pattern: a single 4-hour night flags.

There is no flag for low sleep quality scores alone. Quality at 3 every night for a week reads as a clear signal to the coach but does not auto-flag.

Patterns to watch in the trend

Consistent loss of 30 to 60 minutes vs your typical: often the first sign of building stress, illness, or overreaching.
Late-night drift (sleep onset moving later week over week): typically work stress or screen habit, not training.
Multiple wake-ups (low quality, normal hours): worth checking caffeine intake, evening exercise timing, alcohol.

What you can do

Be honest in logging. Smoothing the numbers does not help.
Add context in the notes field. "Travel", "kid sick", "stressful work week" goes a long way to interpreting a bad week.
Pair with HRV and RHR if you have a device that captures them. Multiple low-recovery signals together is stronger than any one.