BPM: Your Heart Rate and What Changes It
Estimated from a single camera (PPG) reading — an educational estimate, not a medical measurement. State labels (Flow, Focus, Alarm…) are rough, experimental patterns, not emotion detection.
What heart rate is
Heart rate is the number of heartbeats per minute (bpm). It rises when your body needs more blood flow, for example during movement, heat, stress, illness or after caffeine, and falls during rest and sleep. Resting heart rate is a useful everyday health marker when you track it over time.
How this tool calculates it
Your fingertip over the camera changes color slightly with each pulse (photoplethysmography, PPG). The tool finds each pulse peak in the red channel, measures the time between peaks (RR intervals), drops implausible ones, and computes heart rate as 60,000 divided by the average interval in milliseconds. Results outside 40–180 bpm are discarded. The tool works on a rolling 15-second window of fingertip video (about 30 frames per second), finds each pulse peak, keeps only beat-to-beat (RR) intervals between 400 and 1,500 ms that are within 22% of the median, and smooths the displayed numbers so they change gradually.
Typical ranges
About 60–100 bpm
The commonly cited normal resting range for adults. Many healthy people, especially active ones, rest lower.
Below 60 bpm
Often normal in fit people and during deep rest; see a doctor if it comes with dizziness, fainting or unusual tiredness.
Above 100 bpm at rest
Can follow caffeine, stress, dehydration or illness. If it stays high at rest or comes with chest pain or breathlessness, seek medical advice.
How accurate is a camera reading?
Camera heart rate is usually close to a reference device when you hold still in good light, but it is less reliable with movement, cold fingers, heavy pressure or dim lighting. It is an educational estimate, not a medical measurement.
Practical tips
Measure resting HR consistently
For example sitting quietly for a minute after waking, before coffee.
Slow breathing
A few minutes of slow breathing with a longer exhale often lowers heart rate a little.
Long-term habits
Regular aerobic exercise, good sleep and limited alcohol tend to lower resting heart rate over weeks.
The ONDA app is a separate product: it focuses on pulse, breathing and, with an Apple Watch, coherence. It does not use the formulas on this page.
The ONDA Principle
Heart rate is easiest to learn from when you measure it the same way each time and look at the trend.
Ready to measure?
The ONDA app works with your iPhone camera, Apple Watch and Apple Health.