Introducing CYOK Band and CYOK Ring—screenless luxury wearables engineered for locked morning readiness, 4-stage sleep architecture, logarithmic 0–21 Day Strain, strength tonnage, and overnight vitals. No subscription.
CYOK Band · CYOK Ring
Perforated Sport Strap · 0–21 Strain

PVD Stainless Steel · Sleep & HRV

5–7 days CYOK Ring standby (1.5h case charge) · 7–10 days CYOK Band battery.
Engineered without distracting screens and with no subscription. Sign up to be notified as soon as they arrive.
Screenless Precision Engineered for High-Output Days & Recovery.

A distraction-free, screenless biometric strap built for logarithmic Day Strain (0–21), Muscular Load tonnage tracking, continuous autonomic stress monitoring, and deep overnight recovery.
No subscription
Precision Stainless Steel Recovery & Sleep Architecture on Your Finger.

Precision-crafted surgical-grade stainless steel smart ring with recessed palmar optical sensors for nocturnal HRV, 4-stage sleep hypnograms, Recovery Index, and 5–7 day battery life with wireless charging case.
No subscription
Both CYOK Band and CYOK Ring include full access in the native CYOK companion app to all 9 physiological intelligence pillars—from locked morning readiness and 4-stage sleep hypnograms to mechanical strength tonnage, Symptom Radar, and luteal hormone compensation.
A locked, manipulation-free morning score calibrated against your 14-day personal baseline—with zero anxiety.
HRV 74 ms (+9 ms vs 14d baseline) · RHR 49 bpm · Limiting Factor: None
Combines nocturnal HRV (RMSSD), Resting Heart Rate, Sleep Performance, Respiratory Rate, SpO2, and recent 36-hour Strain into a locked morning readiness score that never inflates from daytime wrist movement.
Visualizes Sleep, HRV, Resting Pulse, and Stress Balance against your 14-day personal baseline and automatically identifies your #1 limiting factor each morning.
Designed around real human physiology and mental peace—whether you are recovering from illness or stepping away from daily percentages.
1-tap dark-mode summary card for sharing your daily Readiness, Sleep, HRV, and RHR with your coach or training community.
Select any pillar to explore its interactive telemetry. Included with no subscription.
A locked, manipulation-free morning score calibrated against your 14-day personal baseline—with zero anxiety.
Combines nocturnal HRV (RMSSD), Resting Heart Rate, Sleep Performance, Respiratory Rate, SpO2, and recent 36-hour Strain into a locked morning readiness score that never inflates from daytime wrist movement.
Visualizes Sleep, HRV, Resting Pulse, and Stress Balance against your 14-day personal baseline and automatically identifies your #1 limiting factor each morning.
Designed around real human physiology and mental peace—whether you are recovering from illness or stepping away from daily percentages.
1-tap dark-mode summary card for sharing your daily Readiness, Sleep, HRV, and RHR with your coach or training community.
4-stage sleep hypnograms, nocturnal heart-rate stabilization curves, dynamic sleep debt planning, and gentle haptic wake.
Tracks Awake, REM, Light (Core), and Deep (Slow-Wave) sleep stages alongside sleep efficiency, sleep latency, and restorative sleep percentage.
Analyzes the geometry of your nocturnal cardiovascular curve to reveal how late meals, stress, or optimal recovery shaped your night.
Calculates tonight's exact sleep need by combining your baseline need + today's Day Strain + accumulated Sleep Debt, minus restorative daytime naps.
Automatically classifies 20–180 minute daytime sleep sessions as naps and credits them toward reducing your active sleep debt.
Wakes you via gentle wrist or finger vibration during your lightest sleep stage inside a configurable 15–30 minute window before your final alarm.
Cardiovascular zone load meets mechanical weightlifting tonnage so low-HR heavy sessions are never under-reported.
Translates all-day heart-rate zone time (Zones 1–5) and passive movement into a 0–21 exertion score matched to an optimal daily Strain target derived from your morning Recovery.
Logs resistance exercises, sets, reps, weight (kg), and RPE (1–10) to compute daily mechanical tonnage and Muscular Strain—solving the problem of low-HR weightlifting under-reporting exertion.
Supports Running, Walking, Cycling, Strength Training, HIIT, Yoga/Mobility, and Swimming with real-time HR zones, pace, GPS route mapping, and Dynamic Island / Lock Screen Live Activities.
Passively detects sustained walking, running, cycling, HIIT, and strength bursts from cadence, accelerometer intensity, and HR elevation.
Multi-parameter biometric deviation tracking that catches physiological strain 24–48 hours before you feel run down.
Tracks Resting Heart Rate, Heart Rate Variability (HRV), Respiratory Rate, Wrist/Skin Temperature Delta (±°C), and Blood Oxygen (SpO2) against your 30-day personal corridor, with a 7-night outlier timeline.
Evaluates simultaneous overnight shifts across Skin Temperature, Respiratory Rate, RHR, and HRV to flag No Signs of Strain, Minor Biometric Strain, or Major Biometric Strain up to 24–48 hours before symptoms appear, with a 1-tap Rest Mode trigger.
Real-time daytime autonomic arousal separation, live HRV-guided breathwork, and biological cardiovascular aging velocity.
Distinguishes non-movement HR/HRV autonomic arousal from physical exercise and breaks your day into 4 states: Restored, Relaxed, Engaged, and Stressed.
Built-in guided Physiological Sigh (double inhale + extended exhale) and Coherent 5.5s Breathing coach with real-time wearable HR & HRV delta feedback.
Estimates your biological Health Age vs. chronological age, Pace of Aging multiplier, 14-Day Acute-to-Chronic Workload Ratio (ACWR), and Circadian Social Jetlag.
Turn your body into a clinical N=1 lab—discovering exactly which habits boost or sabotage your HRV and deep sleep.
Logs 25+ habits (Alcohol, Late Meal, Caffeine Cutoff, Magnesium, Sauna, Cold Plunge, Blue-Light Glasses, Breathwork, Creatine, Zone 2, Screen in Bed, etc.) plus subjective Mood, Energy, Soreness, and Stress.
Calculates how each habit shifts your next-morning Recovery (%), HRV (ms), and Resting HR (bpm) on 'Yes' vs. 'No' nights, with a tap-through Habit History Explorer showing every logged date.
Structured N=1 protocols (Magnesium Before Bed, No Alcohol Reset, 6+ Hours Early Caffeine Cutoff, No Late Meals, Daily Breathwork) with progress rings and baseline vs. experiment biometric deltas.
Physiology-aware scoring that respects natural luteal thermal and heart-rate shifts instead of penalizing your recovery.
Tracks Follicular, Ovulatory, Luteal, and Menstrual phases with training and recovery guidance tailored to hormone shifts.
Automatically compensates for natural progesterone-driven +0.35°C skin temperature and +3 bpm RHR rises during the Luteal phase so luteal nights aren't unfairly penalized as poor recovery.
Dedicated optical calibration for wrist, bicep, or finger placement, Quiet Low-EMF sync control, and safe OTA firmware updates.
Dedicated sensor calibration for Wrist, Bicep Band, and Ring / Finger placement to optimize step-rejection and optical PPG pulse-wave filtering.
Pauses continuous background BLE polling and syncs only on manual pull-to-refresh or when placed on the charger.
Full hardware management in the CYOK app with automatic profile recognition and unified biometric history.
Pre-flight BLE link check, ≥ 30% battery safety gate, and cryptographic firmware status verification.
Your biometrics belong to you—with on-device Physician PDF reports, iOS 18 Control Center widgets, and full English & Romanian support.
Includes CYOK Daily Summary, Overnight Vitals, Day Summary, Workout Launcher, Workout Live Activity, and iOS 18 Control Center controls.
Syncs workouts, sleep, HR, HRV, SpO2, and steps with Apple HealthKit, and correlates busy calendar days with physiological daytime stress.
Local on-device generation of a 30-Day Physician PDF Report, a complete JSON Archive, and a spreadsheet-ready Daily Vitals CSV.
1,457+ localized strings natively crafted across English and Romanian.
Join the VIP waitlist to get notified as soon as launch opens and receive 10% Off at Launch. No subscription.