Typically, incorrect heart rate data originates in the Heart Rate Monitor (HRM) and not in the device.

If the device is reporting high heart rate spikes or an irregularly low heart rate there are a few things that may be at fault.

Tips to eliminate erratic heart rate data

• Apply moisture to sensors and contact patch using water;
• Make sure the module had been correctly positioned. the left side should be placed on the left side of your body.    
• Adjust the strap length to fit your chest to make sure the strap is worn snugly and not allowed to slide down your body.
• Re-position the HRM to either your side or back to make sure the contact patch touch firmly with your skin and the LOGO of iGPSPORT is up.                     
• Warm up for 5–10 minutes before activity.
• Try a cotton shirt or wetting your shirt: synthetic fabrics can rub or flap against the HRM creating static electricity which can interfere with HR signals.
• Avoid strong electromagnetic fields and 2.4 GHz wireless sensors, such as high voltage power lines, microwave ovens, 2.4 GHz cordless phones,and other wireless access points.

Other possible causes of erratic heart rate data:

• Improper care of the Premium HRM can cause permanent damage. Review the care article for further clarification
• Medicine, such as Beta blockers, and devices, such as pacemakers or implantable cardiac defibrillators could potentially interfere with HRM readings. Consult a physician regarding this possibility and for possible solutions.
• NOTE: For HRMs that have a removable module, ensure the module is cleaned and dried regularly after use to avoid the build up of rust and corrosion. 

Being aware of possible troubleshooting steps and causes for erratic HRM data will help ensure the best possible experience when using a HRM.