# CYO: Recovery & Strain Tracker — HRV Readiness & Sleep Coach

> HRV Readiness & Sleep Coach (iPhone/iPad app by ADRIAN DANIEL CIOC.)

- Source: https://appshunter.io/ios/app/cyo-recovery-and-strain-tracker/id6756105447 (this page in markdown: same URL + `.md`)
- Developer: [ADRIAN DANIEL CIOC](https://appshunter.io/developer/1818602503)
- Category: Health & Fitness, Lifestyle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 18.6 · 14 MB
- Languages: American English
- Released: 2025-12-07
- Data updated: 2026-10-26

## What is CYO?

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.

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| BioCharge One Year Subscription | $19.99 | per year |
| BioCharge One Month Subscription | $3.99 | per month |


## Is CYO safe?

Not enough ratings yet to assess CYO.

## Is CYO legit?

CYO: Recovery & Strain Tracker appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for CYO is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 5 releases)

### 3.0 — 2026-09-24

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.

### 2.5 — 2026-01-19

New Health Insights:

Vitality Age: A new bio-age metric that compares your real age against your health data (HRV, RHR, Sleep, and Activity) to see if your body is "younger" or "older" than you are.

Sickness Detection (Internal Load Alert): The app now detects when your body is under strain (high RHR/Respiratory Rate) despite low activity, warning you of potential illness or overtraining.

Daily Stress Score: A new 0-100 "Stress Load" bar that visualizes your physiological stress based on HRV.

EKG Integration: View your latest Apple Watch EKG classification directly on the dashboard.

### 2.0.6 — 2025-12-29

Fixed some bugs.

### 2.0.5 — 2025-12-27

We have completely rebuilt the engine to help you recover faster.

New Breathwork Feature: Low recovery? Launch a guided "Resonance Breathing" session directly from the Dashboard to actively improve your HRV.
iCloud Sync: Your Journal and Trends now sync seamlessly across your iPhone and iPad using secure CloudKit technology.
Smarter Algorithms: We moved from static targets to dynamic 30-day baselines. Your Recovery Score is now personalized to your unique physiology.
Smart Bedtime Alerts: Pro users now receive a "Body Battery Check" notification at 9 PM to help plan sleep.
Performance Improvements: Faster load times for historical charts and trend analysis.

### 2.0.4 — 2025-12-25

Bug Fixes & Improvements:

Subscription Restoration: Fixed an issue where the "Restore Purchases" button would not correctly unlock Pro content.

Data Accuracy: Improved the synchronization between HealthKit sleep stages (Deep, REM) and your daily scores.

Performance: Updated core data calculations to be fully compatible with Swift 6 concurrency for a smoother, crash-free experience.

## Apps similar to CYO

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| --- | --- | --- | --- |
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| [PulseState: Recovery & HRV](https://appshunter.io/ios/app/pulsestate-recovery-and-hrv/id6803796804) | — | Free | Health & Fitness |
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All apps by ADRIAN DANIEL CIOC: https://appshunter.io/developer/1818602503

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-26.*