Wearing your M600
Your sport-optimized smartwatch has a built-in heart rate sensor that measures your heart rate from the wrist. To measure wrist-based heart rate accurately, you need to secure the wristband firmly around your wrist, just behind the wrist bone, with the display facing up. The sensor must be touching your skin, but the wristband should not be too tight to prevent blood flow.
When you're not working out, you should wear the wristband a little looser, just as you would wear a normal watch. But you should tighten it up for your training sessions to make sure you get accurate heart rate readings from the wrist. If you have tattoos on the skin of your wrist, avoid placing the sensor right on it as it may prevent accurate readings.
It's a good idea to warm up the skin under the sensor if your hands and skin get cold easily. Get the blood going before starting your session!
In sports where it's more challenging to keep the sensor stationary on your wrist or where you have pressure or movement in muscles or tendons near the sensor, we recommend using a Polar heart rate sensor with a chest strap to get better measurement of your heart rate. See Pairing the Polar app with a heart rate sensor for more information.
Although there are many subjective clues as to how your body is doing during exercise (perceived exertion, breathing rate, physical sensations), none of them are as reliable as measuring heart rate. It is objective and affected by both internal and external factors—meaning you will have a dependable measure of your physical state.