Sahha has launched the Readiness Score — a composite health metric that assesses how well-recovered and prepared a user is for the day’s physical and mental demands.
Where individual biomarkers like heart rate variability or sleep duration describe isolated signals, the Readiness Score synthesizes eight recovery and strain factors into a single daily measure. It answers the practical question that users and product teams care about most: Is this person ready to perform today, or do they need to recover?
The Readiness Score is available now through the Sahha API, joining the existing Activity, Sleep, Mental Wellbeing, and Wellbeing scores.
What the Readiness Score measures
The score combines eight factors across sleep, strain, and physiological recovery:
Sleep factors
Sleep duration — total time spent asleep. The foundation of recovery. Adults regularly sleeping 7–9 hours perform significantly better on measures of attention, memory, reaction speed, and physical work capacity than those sleeping less than 6 hours.
Physical recovery (deep sleep) — time spent in slow-wave sleep, the most restorative phase for the body. Deep sleep drives muscle repair, immune function, tissue growth, and growth hormone release. Losing even one hour of deep sleep per night leads to measurable reductions in muscle recovery and next-day performance.
Mental recovery (REM sleep) — time spent in REM sleep, critical for memory consolidation, emotional regulation, and cognitive function. Each hour less of REM sleep is associated with significant reductions in next-day cognitive performance.
Sleep debt — the accumulated difference between needed and actual sleep over recent nights. Sleep debt compounds — it isn’t resolved by a single good night’s sleep and can take days to recover from.
Strain factors
Walking strain capacity — how the user’s recent daily walking levels compare to their personal baseline. This assesses whether low-to-moderate physical activity is within normal range or represents unusual strain.
Exercise strain capacity — the same assessment for higher-intensity exercise and training loads. Sudden increases in exercise volume relative to baseline signal recovery risk; consistent moderate loads signal adaptation.
Physiological recovery markers
Resting heart rate — lower resting heart rate generally indicates better cardiovascular fitness and recovery. Elevated resting heart rate relative to personal baseline signals incomplete recovery, illness, or accumulated fatigue.
Heart rate variability (HRV) — the variation in time between heartbeats, reflecting autonomic nervous system balance. Higher HRV correlates with better recovery and stress resilience. Depressed HRV signals that the body is still under strain.
How it adapts to available data
The Readiness Score is designed to work across the data spectrum — from smartphone-only users to those wearing dedicated fitness wearables.
With a smartphone alone, the score uses sleep duration, sleep debt, walking strain capacity, and exercise strain capacity. These four factors provide a meaningful daily readiness signal for the majority of users who don’t own a wearable.
With a wearable connected, the score adds deep sleep, REM sleep, resting heart rate, and HRV — substantially deepening the recovery assessment. The physiological markers from wearables capture recovery signals that smartphones can’t detect.
This flexibility matters for product teams. Most health apps have a mixed user base: some users have wearables, most don’t. The Readiness Score provides a useful signal for both groups rather than gating the feature behind hardware requirements.
A forward-looking signal
Most health metrics are retrospective — they describe what already happened. Steps taken yesterday. Hours slept last night. Average heart rate during a workout.
The Readiness Score is forward-looking. It uses yesterday’s data to assess today’s capacity. This distinction changes what products can do with the data:
Adaptive coaching. Adjust today’s workout recommendation based on actual recovery state, not a fixed training plan. A user with high readiness gets a challenging session; a user with low readiness gets an active recovery day.
Intelligent engagement timing. A user with high readiness is more likely to engage with a push notification suggesting a run. A user with minimal readiness is more likely to respond to content about recovery, nutrition, or sleep hygiene.
Strain management. For workplace wellness and insurance platforms, Readiness provides a daily signal of whether employees or policyholders are in a balanced state or accumulating fatigue — enabling proactive interventions rather than reactive ones.
Progress visibility. Showing users that their readiness trending upward over weeks provides tangible evidence that lifestyle changes are working — a powerful retention signal.
Accessing the Readiness Score
The Readiness Score is available through the Sahha API as part of the Scores product. A single API call returns the current score along with the individual factor values that contribute to it — giving product teams both the composite signal and the underlying detail to build rich user experiences.
The Readiness Score guide covers interpretation, contributing factors, and improvement recommendations in detail. The science behind the Readiness Score documents the research evidence supporting each factor.
Available now in both Sandbox and Production environments.