Please check the chest strap. Possible error sources are:
- The chest strap is not placed correctly
- The skin is too cold or too dry
- The sensor contact surfaces are not moistened or are dirty
- Atmospheric or radio interferences occur, eg. From high-voltage lines (above or below ground), overhead cables, electric motors, car motors, mobile phones, aircraft, etc.
- Battery in chest strap is too weak – please replace
- Distance to the chest strap from the watch is too large (max. 60cm / 2ft)
- Signals from other chest straps in a vicinity of less than 2 metres (6ft 6inch) can cause incorrect values.