Weartechs - Wearable techonologies

Wearables Glossary

A quick, practical reference for common terms in AI glasses, smart rings, smartwatches, hearables, and fitness trackers. Use it to understand product pages, compare features, and make better buying decisions.

Sensors & Hardware

  • PPG (Photoplethysmography) – Optical sensor that shines light into capillaries to estimate heart rate and HRV. Used in smart rings and watches for continuous monitoring.
  • Green / Red / IR PPG – Different wavelengths; red/IR improve signals through darker skin and are often used for SpO₂ at night.
  • ECG (Electrocardiogram / EKG) – Electrical measurement of heart activity via electrodes; supports rhythm checks and spot tests in some wearables.
  • SpO₂ Sensor – Estimates blood oxygen saturation; useful as a sleep trend, not a medical diagnosis.
  • Skin Temperature Sensor – Tracks nightly temperature deviation from your baseline; can hint at illness, menstrual phases, or jet lag.
  • Accelerometer (3-axis) – Detects movement, steps, and sleep/wake transitions.
  • Gyroscope – Measures rotation; improves activity detection and gesture accuracy.
  • IMU (Inertial Measurement Unit) – Combo of accelerometer + gyroscope (sometimes magnetometer) for more precise motion tracking.
  • EDA/GSR (Electrodermal Activity) – Measures skin conductance; a proxy for stress/ sympathetic activation.
  • BIA (Bioelectrical Impedance Analysis) – Low electrical current used to estimate body composition or hydration (selected devices).
  • Haptics – Vibration feedback for alerts, timers, and guided breathing.
  • Materials (Titanium, Ceramic, Stainless, PVD/DLC) – Affect weight, scratch resistance, and skin comfort.
  • Water Protection (IP rating / ATM) – IP68 = dust/water resistant; 5–10 ATM ≈ swim-ready (always check brand guidance).
  • Battery & mAh – Battery capacity and real-world battery life per charge.
  • Charging Case/Dock – Portable case or small dock used by many smart rings.

Core Health Metrics

  • Heart Rate (HR) – Beats per minute.
  • Resting Heart Rate (RHR) – Your heart rate at rest; often falls as fitness improves.
  • HRV (Heart Rate Variability) – Variation between beats; higher HRV generally reflects better recovery and stress resilience.
  • RMSSD – A common time-domain HRV metric used by consumer wearables.
  • Respiratory Rate – Breaths per minute; often tracked during sleep.
  • SpO₂ (Oxygen Saturation) – Estimated oxygen level in blood; treated as a trend indicator.
  • Skin Temperature / Temperature Deviation – Nightly change from your personal baseline.
  • Calories (TDEE/BMR) – TDEE = total daily energy expenditure; BMR = basal metabolic rate at rest.
  • METs – Activity intensity unit (1 MET ≈ resting).
  • VO₂max (Estimated) – Indicator of cardiorespiratory fitness derived from pace/heart rate models.
  • Stress Score/Index – Model of autonomic balance using HRV, HR, EDA, and motion data.

Sleep & Recovery

  • Sleep Latency – Time it takes to fall asleep.
  • Sleep Stages (Light, Deep, REM) – Algorithmic estimates based on motion + cardiac signals; helpful for trends, not equal to lab polysomnography.
  • Sleep Efficiency – Time asleep divided by time in bed.
  • Awakenings – Brief wake episodes during the night.
  • Readiness / Recovery Score – Daily score combining HRV, RHR, sleep quality, and temperature deviation to guide “push vs. recover.”
  • Energy Score / Daily Readiness – Dashboard view that blends recent sleep and activity into a simple daily indicator.
  • Circadian Rhythm / Jet Lag – Your 24-hour biological clock; disruptions often show up in sleep timing and temperature trends.

Training & Activity

  • Steps / Active Minutes – Everyday movement; good for baseline activity tracking.
  • Training Load / Strain – Aggregate intensity across sessions; helps balance work vs. recovery.
  • Zones / Zone-Based Coaching – Structured guidance to keep weekly effort in the right ranges.
  • GNSS (GPS/GLONASS/Galileo/BeiDou) – Satellite positioning for outdoor runs/rides (typically on watches, not rings).
  • Cadence / Pace / Power – Performance metrics for running and cycling; require sport-focused devices or accessories.

Device Features & Software

  • Companion App (iOS/Android) – Central hub for trends, insights, Apple Health/Google Fit sync, and data export.
  • Membership / Subscription – Some brands place advanced analytics behind a monthly plan. Consider total cost of ownership.
  • Firmware / OTA Updates – Feature and accuracy improvements delivered over the air.
  • Gestures – Tap/double-pinch actions for camera, alarms, media (varies by device).
  • NFC – Near-field communication for payments or access control (supported on some rings and watches).
  • Bluetooth / BLE / ANT+ – Wireless connections to phones and external sensors.
  • Multi-Device Support – Using a ring for sleep and a watch for workouts under one account/ecosystem.

Privacy, Data & Standards

  • Data Export – Ability to export raw or summary data (CSV, JSON) for personal analysis.
  • Integrations – Sync with Apple Health, Google Fit, Strava and other platforms.
  • Consent & Deletion Controls – In-app settings to manage data sharing, account deletion, and connected services.
  • Baseline – Your personal “normal” for HRV, RHR, temperature, etc.; trends are compared to this baseline.
  • Clinical vs. Wellness – Consumer wearables provide wellness insights; they do not diagnose medical conditions.

Buying & Fit

  • Sizing Kit – Trial rings or sizers to find a comfortable, snug fit that improves signal quality.
  • Fit (Index vs. Middle Finger) – Index or middle finger often yields the cleanest nocturnal signals.
  • Finish & Durability – Coatings like PVD/DLC and materials (titanium, ceramic) affect scratch resistance.
  • Battery Life & Charge Time – Real-world days per charge and minutes to a day’s top-up.
  • Water Use – Check brand guidance for showering, swimming, sauna and salt-water exposure.
  • Return/Resize Policy – Important for rings where fit directly affects comfort and accuracy.
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