The heart rate sensor can be used during sports such as cycling, running, and fitness, but it is not supported for use during swimming.

If excessive sweat and salt accumulate on the chest strap of the heart rate sensor, it will affect the accuracy of the heart rate sensor measurement data.

1. Please rinse the chest strap with clean water after each use.

2. Please do not use a washing machine or dryer to clean and dry the chest strap

3. Please hang or lay the sensor flat to dry.

The H303 is specifically designed for exercise, and its algorithm and hardware design have been optimized for exercise.

If users must test their resting heart rate, please keep the sensor electrode moist, and keep the body seated and not lying down as lying down can cause poor contact between the electrodes and the skin.

After exercise, please remove the sensor from the chest strap. The chest strap is wet after exercise, and the sensor can still detect extremely weak voltage signals. When wearing a heart rate sensor normally, this voltage signal will be filtered and will not affect the accuracy of heart rate detection. If the heart rate sensor is not removed, it will also automatically sleep after 1-3 minutes.

The smartwatch and smart bracelet use the PPG to measure heart rate.

Blood contains heme, and the degree of absorption and reflection of light by heme with different oxygen levels also varies. When the heart contracts, the heme density is high and it absorbs more green light. When the heart relaxes, the heme density is low and more green light is reflected. Wearing smartwatches and bracelets on the wrist can easily leak light. The light emitted by fluorescent lamps and energy-saving lamps can cause data errors. The relative movement between optical sensors (LEDs and photodetectors) and the skin can also reduce the sensitivity of light signals.

The chest strap uses a dry electrode, but when the dry electrode is first placed on the body, the impedance is very high. This means that the ECG signal may decay into a small signal. The problem of dry electrode activation usually lasts for a short time. Once the wearer has fully exercised and started sweating, the impedance can be reduced and the signal level can be increased, and the heart rate data will return to normal.