CYO: Recovery & Strain Tracker
HRV Readiness & Sleep Coach
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Turn Apple Watch biometrics into elite physiological telemetry. Track resting HRV, cardiovascular strain, sleep recovery, and daily readiness without subscriptions.
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, Resting HR, Sleep, and Respiratory Rate.
- Instantly identify whether biometrics are within your normal biological range, suppressed, or elevated.
- Weekly Performance Assessments (WPA) tracking recovery day distributions (Green, Yellow, Red) and net volume changes.
- Estimated VO2 Max, 1-minute Heart Rate Recovery, and Vitality Biological Age advantage.
ELITE WORKOUT TELEMETRY
Detailed session analysis for every activity:
- Individual workout strain scores (0.0 to 21.0).
- 5-zone heart rate distribution bars.
- Aerobic Training Effect (0.0 to 5.0) and Anaerobic Training Effect (0.0 to 5.0).
- Estimated post-workout recovery hours.
100% PRIVATE ON-DEVICE APPLE INTELLIGENCE
Powered by on-device Apple Foundation Models. Your health data is processed exclusively on your device, ensuring total privacy with zero cloud latency and full offline capability.
CYO integrates seamlessly with the Apple Health app (HealthKit) to read heart rate, HRV, resting heart rate, sleep analysis, workouts, respiratory rate, and active energy.
Terms of Use (Standard Apple EULA):
https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy:
https://www.notion.so/BioCharge-Privacy-Policy-2bff568e99bc80eebf94c9bcd55f710e?source=copy_link
Disclaimer: CYO is not a medical device and is intended solely for general fitness, athletic telemetry, and wellness purposes. Consult a physician before beginning any new training program.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Version 3.0 : The Elite Physiological Telemetry Update
- 24-Hour Continuous Cardiac Timeline: Drag across your intraday heart rate and autonomic stress curve with interactive touch-scrubbing.
- Acute-to-Chronic Workload Ratio (ACWR): Track your 7-day acute strain against your 28-day chronic baseline to prevent overtraining and optimize progressive overload.
- Circadian Sleep Coach: Dynamic bedtime, wind-down, and wake schedule based on real-time sleep debt and strain demand.
- Pro Analytics Hub: View 30-day personal baseline normal-range tunnels (mean +/- 1 standard deviation) for HRV, resting heart rate, and sleep.
- Workout Telemetry: Per-workout strain scores (0.0 to 21.0), 5-zone HR duration bars, aerobic and anaerobic training effect, and estimated recovery clearance hours.
- Apple Foundation Model Engine: 100% private, on-device Apple Intelligence providing daily physiological briefings without cloud dependencies.
- Refined subscription experience with transparent monthly and annual options.
The developer, ADRIAN DANIEL CIOC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Health & Fitness
- Purchases
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- ADRIAN DANIEL CIOC
- Size
- 14.3 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 18.6 or later.
- iPhone
Requires iOS 18.6 or later. - Mac
Requires macOS 15.6 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.6 or later.
- iPhone
- Languages
- English
- Age Rating
9+
- 9+
- Contains
Health or Wellness Topics
- In-App Purchases
Yes
- BioCharge One Month Subscription $3.99
- BioCharge One Year Subscription $19.99
- Copyright
- © 2026 Adrian Daniel Cioc