It stands to reason that, like a Valentine's Day heart, a red heart emoji means love. But what does a white heart emoji mean? And how do you use it?

Heart rate zone 1, or just “Zone 1” usually appears as a blue or similarly cool-toned color on fitness trackers, and is generally around 50-60% of your maximum heart rate according to Polar.

If you're wondering what all the different colour heart emojis mean and when to send each one, here's a comprehensive guide on how to use all the heart emojis ...