Recovery Tracking: Training Readiness Score
Training adaptation does not happen during exercise — it happens during recovery. The stress of a workout is only a stimulus; the adaptation occurs in the subsequent hours and days when the body repairs and rebuilds stronger than before. An athlete who trains hard every day without adequate recovery is accumulating fatigue without accumulating adaptation. Fitiv Pulse's recovery tracking system makes the invisible process of recovery measurable and actionable.
What is a Training Readiness Score?
A training readiness score is a daily composite metric that estimates how recovered your body is from previous training stress and how prepared it is to absorb a new training stimulus. Unlike a single-variable metric (heart rate alone, or sleep duration alone), a readiness score synthesizes multiple physiological signals to produce a more complete picture of recovery state.
Fitiv's readiness score runs from 0-100 and is calculated fresh each morning from three primary inputs:
- Heart rate variability (HRV): Morning RMSSD reading compared to your personal 7-day and 30-day baseline (approximately 50% weight in the composite)
- Sleep score: Duration, consistency, and estimated quality from the previous night (approximately 35% weight)
- Resting heart rate: Deviation from personal baseline resting HR (approximately 15% weight)
Training load from the preceding days informs the expected recovery trajectory — if you ran a hard long run two days ago, the algorithm accounts for the fact that some HRV suppression is expected and normal.
What the Score Means in Practice
- 75-100 (Green): Well-recovered. The body is primed for a quality training stimulus — high-intensity sessions, long efforts, or demanding strength work will be well-tolerated and should produce strong adaptation.
- 50-74 (Yellow): Moderate readiness. Aerobic work, moderate-intensity sessions, or reduced-volume training is appropriate. Avoid maximum efforts.
- 25-49 (Orange): Below-average recovery. Easy active recovery — Zone 1-2 movement, mobility work, or light cross-training — is advisable. Forcing intensity here accumulates fatigue without proportional benefit.
- 0-24 (Red): Poor recovery. Rest or very gentle movement is indicated. Training hard in this range is the primary driver of overreaching and injury in self-coached athletes.
How Fitiv Tracks Recovery
HRV as the Primary Recovery Signal
Heart rate variability is the most sensitive physiological marker of recovery status available without laboratory testing. The autonomic nervous system responds to training stress by suppressing parasympathetic activity, which reduces HRV. As recovery progresses, parasympathetic activity — and HRV — rebounds.
The key is trend, not absolute value. A single morning of low HRV may reflect a poor night's sleep, slight dehydration, or measurement artifact. Five consecutive days of below-baseline HRV alongside elevated resting heart rate is a reliable signal of accumulated fatigue.
Fitiv collects HRV from Apple Watch or any Bluetooth HR monitor (Polar H10, Wahoo TICKR X, Scosche Rhythm+) at consistent morning measurement times. Measurement consistency is critical — readings taken in different positions, at different times of day, or under different conditions introduce noise that reduces the score's reliability.
Sleep Score Integration
Sleep is the primary recovery mechanism for both physical and neurological fatigue. During deep sleep, growth hormone release peaks, protein synthesis occurs, and the neural fatigue accumulated during hard training is cleared. Inadequate sleep — either in duration or quality — directly impairs recovery even when training load is appropriate.
Fitiv's sleep score draws from Apple Watch sleep tracking, which estimates sleep duration, time in bed, and broad sleep stage categories. The score penalizes both insufficient sleep (below 7 hours) and highly fragmented sleep, and rewards consistent sleep timing (irregular sleep schedules suppress recovery quality even at adequate total duration).
Resting Heart Rate Trend
Elevated resting heart rate — measured in the morning before rising — is a classical indicator of incomplete recovery. The mechanism is direct: sympathetic nervous system activation from accumulated training stress increases baseline cardiac output, reflected in higher resting HR.
A resting HR elevation of 5 bpm or more above personal baseline is considered significant. The clinical literature on overtraining consistently identifies elevated resting HR as an early indicator of non-functional overreaching, often appearing 1-2 weeks before subjective performance decline.
Recognizing and Avoiding Overtraining
Overtraining syndrome (OTS) is a distinct clinical condition in which accumulated training stress exceeds the body's capacity to adapt, producing prolonged performance decline that persists despite adequate rest. It is distinct from normal fatigue and typically requires weeks to months of reduced training to resolve. Functional overreaching — a milder, recoverable version — resolves with 1-2 weeks of rest.
Fitiv's recovery tracking is designed to detect the precursors of overreaching before it becomes established. The warning signs it monitors:
- HRV trend decline over 5+ consecutive days without recovery between sessions
- Resting HR elevation of 5+ bpm above 30-day average
- Acute:Chronic Workload Ratio above 1.5 (recent training load significantly exceeds habitual training load)
- Sleep score decline coinciding with training load increases
When these patterns emerge simultaneously, Fitiv flags a recovery concern and recommends a reduction in training load, regardless of what the training plan specifies. Adherence to this feedback — even for athletes who feel subjectively fine — is the primary value of objective recovery monitoring.
Subjective sense of fatigue is a lagging indicator. Athletes experiencing functional overreaching frequently feel normal or even energetic in the early stages, despite measurable physiological markers of stress accumulation. Objective tracking catches what subjective perception misses.
Using Recovery Data to Plan Training
The most effective application of readiness scores is not to determine whether to train, but to determine how to train. Green-day training should be reserved for hard sessions — intervals, threshold work, long efforts. Red and orange days should be easy regardless of what the training plan says.
This approach, known as HRV-guided training, has empirical support. A 2016 study in the International Journal of Sports Physiology and Performance found that athletes using HRV-guided training over 16 weeks improved VO2 max more than a matched group following a fixed plan, at equivalent total training volume. The difference was in intensity distribution: HRV-guided athletes accumulated more high-quality hard sessions because they timed them during genuine recovery windows.
Why Recovery Tracking Matters for Athletes
Most athletes over-train in a specific way: they fail to make easy days easy enough. When every session is run at a moderate-hard effort, the accumulated fatigue prevents both genuine aerobic base development (which requires sustained Zone 1-2 work) and genuine high-intensity adaptation (which requires full recovery before each hard session).
Recovery tracking makes the binary nature of productive training visible. Meaningful adaptation comes from the combination of adequate stress and adequate recovery — not from maximal stress applied continuously.
Frequently Asked Questions
Q: My recovery score is low but I feel fine. Should I still take it easy? A: Subjective feelings of readiness are unreliable, particularly during gradual fatigue accumulation. The physiological markers that Fitiv tracks — HRV, resting HR — can be suppressed before you consciously feel the effects. However, a single low score in isolation (when other signals are normal) is less concerning than a multi-day pattern of low scores. If you consistently feel fine on low-score days without negative consequences, the model will calibrate to your individual response pattern over time.
Q: How is Fitiv's recovery score different from WHOOP's recovery score? A: Both systems measure HRV, sleep, and resting heart rate and combine them into a recovery metric. WHOOP requires proprietary hardware (the WHOOP strap) and a monthly hardware subscription. Fitiv works with Apple Watch and any Bluetooth HR monitor you already own. The underlying physiology is the same; the hardware flexibility and cost model differ.
Q: Does recovery tracking account for non-training stress (work stress, travel, illness)? A: Fitiv tracks physiological signals that reflect total allostatic load — not just training stress. Work stress, travel, illness, and alcohol all affect HRV and resting HR in measurable ways. The recovery score will reflect these stressors even if no workout is logged. You can optionally add lifestyle notes in the app to tag specific factors for later reference.
Q: How many days of data does Fitiv need before recovery scores are reliable? A: The score is calculated from day one using population-level baselines. It becomes progressively more accurate as personal baseline data accumulates. After 2 weeks of consistent morning measurements, the score is calibrated primarily to your individual data. After 6-8 weeks, the model has sufficient history to distinguish meaningful deviations from measurement noise with high reliability.