How to prevent missing heart rate signals

Following these instructions will help you ensure reliable heart rate measurement during the classes.


1. Replace the heart rate sensor's battery when the charge level gets low


The battery lifetime of the Polar H7 heart rate sensor is 200 hours.  If a heart rate sensor's battery charge level has lowered, the Polar Club app notifies you by displaying a battery low symbol:

If the symbol appears on the screen during a class, there’s no need to worry about the battery running out right away. There’s still enough battery life left to finish the class. However, the battery should be changed as soon as possible.

2. Make sure that the participants know how to wear the heart rate sensor correctly


In order for the heart rate sensors to work properly (detect and transmit heart rate data), wear the heart rate sensor as instructed below:

  1. Wet the plastic electrode areas of the strap under running water and make sure that they are well moistened.
  2. Attach the connector to the strap.
  3. Adjust the strap length to fit tightly but comfortably. Tie the strap around your chest, just below the chest muscles, and attach the hook to the other end of the strap.
  4. Check that the moist electrode areas are firmly against your skin and that the Polar logo of the connector is in a central and upright position.


The heart rate sensor consists of a strap and a connector. The plastic electrode areas on the reverse side of the strap (A) detect heart rate. The connector (B) sends the heart rate signal to the Polar Club app.

3. Care for the heart rate sensors


The heart rate sensor is a high-tech instrument that should be kept clean and treated with care.
The caring instructions below will help you keep the heart rate sensors working well and avoid any issues in heart rate measurement.

Connector: Detach the connector from the strap after every use and clean the connector with a mild soap and water solution. Never use alcohol or any abrasive material (e.g. steel wool or cleaning chemicals).

Strap: Wash the straps regularly in a washing machine at 40 °C (104°F) to ensure that you always have clean straps available for those wanting to borrow a heart rate sensor. Detach the connector from the strap before washing. Always use the washing pouch (included in the set). Do not use bleach or fabric softener.

Never dry the strap or the connector in a dryer!

Storing: Dry and store the strap and the connector separately to maximize the heart rate sensor battery lifetime. Keep the heart rate sensor in a cool and dry place. Do not store the heart rate sensor wet in non-breathing material, such as a sports bag, to prevent snap oxidation. Do not expose the heart rate sensor to direct sunlight for extended periods.