You have gaps in HRV data or it seems inaccurate
If your HRV (Heart Rate Variability) data seems inaccurate or if you get different results than you do with a heart rate monitor, perform the following steps:
- Make sure your watch is properly positioned on your non-dominant wrist, 1 cm from the wrist bone.
- Make sure you wear your watch tightly enough. It shouldn't be able to move around your wrist, but should be loose enough to allow blood to flow.
Note: You may notice inaccurate HRV data if you wear a metal or leather wristband. - Make sure the sensor below your watch emits a blinking green light when the watch display is on.
- Make sure your watch is clean, so the LEDs are not obstructed by dust or dirt.
- Make sure your wrist is moisturized but neither overly dry nor sweaty or overly wet.
You can position your watch on the lower part of your wrist. Note that we cannot guarantee the accuracy of the heart rate data, because the product is not aimed to be positioned on the lower part of your wrist.
To obtain the most accurate results please follow these additional guidelines:
- The watch should be worn tightly enough that the sensor on the back of the watch face touches your skin.
- Wear the watch 1 to 2 finger width away from your wrist bone. Getting too close to or touching the wristbone can cause accuracy issues.
- Use the wristband Withings provides with your watch.
- Make sure that your watch stays in place during exercise. If it moves around at all, tighten your band one notch.
- Make sure your band is secure, but not too tight. It should be comfortable and allow proper circulation.
- Wear the watch your non-dominant wrist, as this often provides the most accurate results. We encourage testing on both wrists, however.
Additional factors that prevent good HRV recordings:
Skin perfusion
Skin perfusion, or how much blood is flowing through the skin, varies among individuals and according to the environment. In certain circumstances, the watch may not be able to provide an accurate heart rate measurement.
Skin and blood properties
The technology used by the watch is based on the light absorbed by your skin and blood. Any permanent or temporary changes to your skin, such as tattoos, sweat, or even hair on the wrist may affect the measurements.
Environment
Environmental factors may affect the ability of the watch to take an accurate measurement. For example, water may obstruct or modify the light dispersion, and cold weather may impact skin perfusion.
Excessive Motion
The watch needs to stay securely in place to provide a heart rate measurement. Excessive movement during the night that causes force to the wrist may not allow the watch to provide an accurate HRV.
The HRV data doesn't match the data of another tracker
Typically this is caused by a different algorithm being used between your Withings device and another tracker. However, if you follow the above guidelines on how the watch should be worn, you should receive accurate HRV measurements.