Readiness score: what it is and how Salvor works out your daily form

What a readiness score is

A readiness score answers one simple question each morning: how well prepared is your body for strain today? Several signals from the night and the last few days are combined into one number between 0 and 100.

The number is a calculation, not a measurement. No sensor measures "readiness" directly. The score pulls together values that say something about recovery and makes them readable at a glance. In Salvor it is called daily form (Tagesform).

What goes into Salvor’s daily form

Daily form is a weighted mean of four inputs: body signals (HRV, resting heart rate, breathing rate, temperature) count most at 45 %, sleep 30 %, training balance 15 % and stability 10 %. A long night alone therefore does not hide a strained body. Stability drops by 20 points for every body signal that deviates unusually in the direction of strain. Within the body signals the weakest one pulls on top: if one is clearly in the strain range (below 60 of 100), half of its distance to that mark is taken off as well so the others cannot hide it.

If an input is missing, for example because the watch was off at night, the weights of the others are scaled up to match. A missing value never counts as a bad value. Without sleep and without body signals, Salvor shows no daily form.

Two things come on top: sleep debt from the last 14 nights takes off up to 10 points. And if two body signals deviate at once, daily form stays at 60 at most, with three or more at 45. Salvor treats this pattern as a possible sign of strain or an infection starting. The levels: "Strong" from 67, "Solid" from 34, "Take it easy" below.

Why your own baseline matters

Every input is compared with your own range of the last 28 days, not with a general normal value. A resting heart rate of 62 or an HRV of 40 ms can be good for one person and a warning sign for another. This is also how sports scientists follow athletes’ HRV^{1, 2}.

That is why Salvor needs time at the start. Daily form appears after 14 nights with data. Until then the app does not know your range well enough, and a number would be a guess. Sleep is scored from the first night.

How Oura and WHOOP do it

Oura lists nine contributors to its readiness score: resting heart rate, HRV balance, body temperature, recovery index, sleep, sleep balance, sleep regularity, previous day activity and activity balance. They are measured against your personal averages, and according to Oura learning those takes up to two weeks. The scale runs from 0 to 100: 85 and above is "Optimal", 70 to 84 "Good", 60 to 69 "Fair", below that "Pay attention"³.

WHOOP describes Recovery as a daily measure of how prepared your body is to perform, as a percentage from 0 to 100. According to its developer documentation, resting heart rate and HRV go into it, and on newer devices also blood oxygen and skin temperature⁴.

How much each input counts is not stated on the pages we read for either provider. The numbers are therefore not comparable: an Oura readiness of 80, a WHOOP Recovery of 80 % and a daily form of 80 are based on different inputs and scales.

What the research says and what it does not

The individual ingredients are well studied, the finished score less so. A meta-analysis of HRV-guided training found that people who steer their training by HRV improve vagal HRV indices more than with a fixed plan, once methodological factors are accounted for. For maximal oxygen uptake and endurance performance the differences were small and not statistically significant⁵.

A systematic review of studies in athletes reached a notable result: self-reported well-being reflected training load with better sensitivity and consistency than the commonly used objective measures. The two kinds of measures mostly did not agree⁶. So your own feeling is a signal in its own right and worth taking seriously.

To be honest: Salvor’s weights and thresholds are mostly design choices. They are reasoned and tested, but no validation study shows that daily form predicts well-being or performance.

How to use your daily form

Treat daily form as orientation, not as a rule. A low number means "maybe go a little easier today"; no number forbids you anything. A trend over several days says more than a single day.

When the number and your feeling disagree, let your feeling count. If you feel bad with a good daily form, the number does not cancel that out. If you feel good with a low one, that is just as much a hint you may take seriously. The number never decides for you.

When to see a doctor

Daily form is information about general wellness, not a diagnosis. A low number after a short night or hard training is normal. If tiredness, fever, an unusually high resting heart rate or symptoms such as a racing heart, dizziness, shortness of breath or chest pain persist, talk to a doctor, whatever the score shows. In an emergency, call 112.