CYO: Recovery & Strain Tracker

CYO transforms your Apple Watch and Apple Health biometrics into an elite physiological telemetry system. Designed for endurance athletes, strength trainers, and performance-minded individuals, CYO translates complex cardiovascular and autonomic nervous system data into clear, actionable protocols for daily training and recovery.

CONTINUOUS 24-HOUR CARDIAC & STRESS TIMELINE
View your entire day unfolded on an interactive timeline:
- Drag your finger across the intraday curve to inspect exact timestamps, heart rate, and cardiovascular zones.
- Switch between continuous Heart Rate and Autonomic Stress Load (0 to 100) to pinpoint periods of sympathetic activation versus parasympathetic recovery.
- Track resting heart rate, peak workout heart rate, and active zone minutes.

AUTONOMIC RECOVERY & READINESS
Know when to push your limits and when to prioritize rest:
- Calculated from a rolling 30-day baseline standard deviation (z-score) of Heart Rate Variability (HRV SDNN / rMSSD) and Resting Heart Rate.
- Accounts for sleep performance ratios and respiratory rate shifts.
- Receive daily readiness classifications: Primed, Adequate, or Rest & Recover.

TRUE LOGARITHMIC DAY STRAIN (0.0 TO 21.0)
Cardiovascular load is not linear. CYO calculates daily strain using percentage of Heart Rate Reserve (Karvonen formula):
- Exponential zone weighting across Active Recovery, Aerobic Base, Cardio Tempo, Threshold, and Anaerobic Peak.
- Dynamic Optimal Strain Tunnel prescribes a targeted workload range based on your morning recovery score.

ACUTE-TO-CHRONIC WORKLOAD RATIO (ACWR)
Apply the sports science gold standard to prevent injury:
- Compares 7-day Acute Load against 28-day Chronic Load.
- Visual meter guides you to remain in the progressive overload sweet spot (0.8 to 1.3) while avoiding overreaching or soft-tissue injury risk.

CIRCADIAN SLEEP COACH & CONSISTENCY
Maximize restorative sleep and biological hormone anchoring:
- Sleep Consistency score measures bedtime and wake time variance over rolling 7-day periods.
- Dynamic sleep need itemizes your baseline requirement, accumulated sleep debt, and extra strain demand.
- Actionable schedule outputs exact target times for Wind Down, Sleep By, and Wake Up.

PRO ANALYTICS & 30-DAY BASELINE TUNNELS
Move beyond isolated daily numbers:
- 30-day statistical baseline tunnels (shaded mean +/- 1 standard deviation) for HRV, Restin