Cardio Diary - Heart Rate

Curious about HRV but not ready to buy a smartwatch? Cardio Diary lets you explore heart rate variability using just your phone camera. No extra devices, no subscriptions to hardware, no wrist straps. HOW IT WORKS Place your fingertip on the camera lens and flash. The app detects subtle color changes in your skin caused by blood flow. Within 30 seconds, you get readings of your heart rate and HRV. WHY USE YOUR PHONE Smartwatches and fitness bands can cost hundreds of dollars. Cardio Diary gives you a way to explore HRV tracking before investing in dedicated hardware. Your phone is always with you, always charged, and now it can measure your pulse too. WHAT YOU CAN MEASURE Heart Rate (BPM) Get instant pulse readings anytime. Check your resting heart rate in the morning or see how it changes throughout the day. Heart Rate Variability (HRV) HRV measures the variation in time between heartbeats. The app calculates RMSSD, a metric commonly used in wellness apps and research. Track your personal patterns over time to see what affects your readings. Relaxation Score See a simple score based on your HRV reading. Notice patterns in your daily routine and how different activities affect your numbers. KEY FEATURES - Camera-based PPG measurement - Real-time pulse waveform display - Age-adjusted HRV reference ranges - Measurement history and trends - Signal quality indicator - Works offline with no account required - Data stays private on your device WHO IS THIS FOR - People curious about HRV without buying a smartwatch - Anyone who wants to try pulse tracking for free - Those interested in daily heart rate patterns - People exploring mindfulness and body awareness MEASUREMENT TIPS For consistent readings, measure in a similar state each time. Sit down, relax for a minute, then measure. Readings can vary based on caffeine, activity level, and time of day. Cover both the camera lens and flash completely with your fingertip. Hold still during the measurement. PREMIUM FEATURES Free users can take 3 measurements per week. Upgrade to Premium for unlimited measurements and full history access. IMPORTANT NOTICE Cardio Diary is for personal curiosity and wellness exploration only. It is not a medical device and cannot diagnose, treat, or prevent any health condition. Do not use this app to make decisions about exercise, medication, or health treatment. Always consult a healthcare professional for medical advice. Download Cardio Diary and start exploring your heart rate patterns.

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