Recovery: last night against your normal.

What Recovery tells you

Recovery answers one question each morning: how did last night compare with what’s normal for you? HRV and resting heart rate carry most of the weight, because they move when your body is still absorbing a hard day, a short night, alcohol, illness or stress.

• Primed 67–100
• Balanced 34–66
• Restore 0–33

Each state comes with a focus for the day, and it sets your Load target:

• Primed, a quality day. Threshold or intervals will land well.
• Balanced, a steady day. Endurance or tempo fits; save the hard intervals.
• Restore, an easy day. A walk, mobility or a short Zone 1–2 session.

Tap the score in the app to see what moved it. Each input shows as helping, holding back or normal, with its value against your normal range.

What goes into it

HRV here is RMSSD: the root mean square of the differences between successive heartbeats, in milliseconds. It varies widely from person to person, which is why Keely only ever compares you with you.

How the score is computed

1. Distance from normal. Each input becomes a z-score: how many standard deviations it sits from your baseline. The sign flips where lower is better, so a positive z always helps.
   • Breathing rate and skin temperature only count against you, since a change in either direction can mean something is off.
   • Sleep is measured against your need, not your average: 85 % of your need counts −1, and sleeping past your need helps, up to +1.
   • Every z is capped at ±2.5, so one strange reading can’t dominate.
2. Blend. The z-scores are weighted and added up.
3. Score. The blend goes through a logistic curve, so the score moves most around your normal and flattens at the ends.

z        = (value − baseline) ÷ SD
z sleep  = (asleep ÷ need − 1) ÷ 0.15
c        = 0.45 zHRV + 0.25 zRHR + 0.20 zSleep
         + 0.05 zBreathing + 0.05 zTemperature
Recovery = 100 ÷ (1 + e^(−1.6 × c))

A worked example. HRV one standard deviation above normal (+1), resting heart rate half a deviation below (+0.5), 95 % of your sleep need (−0.33), breathing at normal (0) and skin temperature half a deviation off (−0.5). The blend is c = 0.45 + 0.125 − 0.067 + 0 − 0.025 = 0.48, so Recovery is 100 ÷ (1 + e^−0.77) = 68 %, Primed.

Standard deviations have floors, so a run of near-identical nights can’t make small changes look huge: 5 % of the mean for HRV, 1 bpm for resting heart rate, 0.3 breaths a minute and 0.2 °C.

Your normal, and calibration

• Your normal for each signal is a weighted average of your last 30 nights. Recent nights count more: a night a week ago counts half as much as last night.
• The normal range shaded behind HRV and resting heart rate in the app is your baseline ± one standard deviation.
• The first score arrives once HRV and resting heart rate each have 3 nights. Until then Recovery shows Calibrating, never a guess.
• Fully personal after 14 nights. A night never counts toward its own baseline.

When the score arrives

Recovery is computed as soon as your night’s beat intervals and heart rate have synced from the Loop. The Loop’s own sleep staging can take a little while after you wake, and until your night is in, Today says Reading your night rather than showing an early number.

Every morning’s score is kept. The Recovery calendar at the foot of Today shows each one as a ring, and tapping a day shows its numbers.

Frequently asked questions

Keep reading