Sometimes, my watch gives me crazy readings such as 221 bpm at rest for my heart beat when I use the chest strap transmitter. What causes that and how can I prevent it? Could it be my WiFi internet network that interfere with the chest strap signal? Thanks.

First, you want to adjust the fit of the chest strap. <br /> <br /> Moistening give a more comfortable fit by reducing friction and will also help create a better connection between your skin and the receiver. It can also increase the lifespan of your belt.<br /> <br /> When properly looked after, your heart rate monitor watch should far outlive the chest strap. More often than not any problems you find with the watch can be traced to the chest strap or the batteryIn terms of conservation, the most important thing you can do is ensure that your watch is no longer monitoring after you return from your run. <br /> <br /> This should be easily achievable through the interface on the watch. Separating the watch from the monitor component by a significant distance will ensure that no unwanted connections continue after use.<br /> <br /> Where possible, make sure to remove the electrical component before rinsing the strap with some running tap water. If the watch and electrical component are particularly dirty, you can use a damp cloth to wipe them down, before putting everything aside to dry. Be sure not to leave the chest strap in the sun as this can cause the material to deform, making it itchy and uncomfortable to wear.