Why is the ECG waveform not clear and sometimes not stable?

The small sawtooth waveform are noises generated by muscle electricity, movement and/or poor conductivity. To minimize noises, please:

1. Sit down, keep calm and relax.
2. Put hands on table or thigh to relax arms.
3. Hold the device gently and steadily, make sure that your finger and palm have a stabilizing contact with ECG electrodes.
4. Moisten fingers and/or palm to improve conductivity when necessary. Dry skin or thick stratum corneum affects conductivity.