What a readiness score actually measures
Rather than a medical diagnosis, a readiness score is a daily summary of recovery signals. The core idea is comparison against your baseline: today's data is weighed against your typical range, so the score reflects change relative to your normal rather than how you compare to anyone else. Because nervous-system recovery and population norms vary widely, individualized baselines tend to be more meaningful than fixed thresholds.
Heart-rate variability is one of the most studied inputs. A 2020 meta-analysis in Frontiers in Physiology reported that resting HRV is responsive to training and recovery status across athletic populations, which is part of why wearables lean on it so heavily. Expert consensus is that no single metric is decisive — readiness is most useful when it combines several signals and is read as a trend.
Common inputs and related signals
Readiness models differ by product. The current Reps score uses sleep, resting heart rate, and recent strain. HRV remains a separate trend you can compare with the score for extra context. The common signals below are summarized with real-world sources so you can dig deeper.
Heart-rate variability (HRV)
HRV is the beat-to-beat variation in your heart rhythm and can add context to recovery trends. Reps keeps HRV separate from the current Readiness Score, so you can compare both over time without treating one reading as the whole story.
A 2019 systematic review in Sports Medicine found that HRV-guided training led to similar or better fitness outcomes than predefined plans in most studies reviewed. Sports Medicine (2019)
See how Reps tracks this →Resting heart rate (RHR)
Resting heart rate is your heart rate at rest, usually measured overnight or on waking. An elevated RHR versus your normal range can accompany incomplete recovery, illness, or high stress, so it is most useful as a multi-day trend rather than a single reading.
Large cohort research links a lower resting heart rate with better cardiovascular fitness, making personal RHR trends a useful recovery signal. Journal of the American Heart Association
See how Reps tracks this →Sleep
Both how long and how well you sleep shape next-day readiness. Deep and REM sleep support physical and cognitive recovery, so short or fragmented nights tend to pull a readiness score down.
The American Academy of Sleep Medicine and Sleep Research Society recommend adults regularly sleep 7 or more hours per night to support optimal health. AASM / Sleep Research Society consensus
See how Reps tracks this →Recent strain
Recent strain captures how much physical stress you have absorbed from recent activity. A demanding stretch without enough recovery can pull the next readiness score down.
Sports-science research on the acute:chronic workload ratio associates rapid spikes in training load with higher injury risk, underscoring why recent activity belongs in recovery context. British Journal of Sports Medicine
See how Reps tracks this →How to act on your readiness score
A score is only useful if it changes a decision. Exact bands differ between products, but the practical guidance below maps a typical 0–100 scale to how you might adjust a session. These are general training principles, not personalized prescriptions.
High (≈70–100)
Moderate (≈40–69)
Low (≈0–39)
Read the trend, not the day
Not medical advice
See your own readiness score
Reps brings health, nutrition, training, and recovery together on iPhone and Apple Watch — use one part of your day on its own or see the whole picture. Reps builds the score from sleep, resting heart rate, and recent strain — no extra recovery band required. Your HRV stays available as a separate trend for additional context.
Download Reps on the App Store