Personalization and recommendations are a staple of many services, particularly music services that aim to provide their users with music they want before they know they want it. Spotify could be boosting that idea in the future with a recommendation system that dishes up music based on the user's current heart rate, ensuring there are some tracks at hand for every occasion.
The feature doesn't exist yet, but is apparently an idea behind tossed around behind closed doors at the music streaming service, and wouldn't necessarily be limited to exercising, which is what first comes to mind when heart rates are mentioned. Instead, the feature could -- theoretically -- be used in conjunction with different sensors for heart rate, body temperature, and more to try and determine what is going on with the user in that moment.
The sensors could be worn on the skin, or they could be embedded within a smartphone that could detect them when held. The information shuttled to Spotify could then be used to decide if the user is sleeping, driving, running, or maybe even feeling a bit passionate at the moment. Using that listener's existing listening habits could then better shape an algorithm that uses the body information.
Combining it all together, the service could then potentially offer up a playlist that is tailored towards whatever activity is happening in the moment. Said Spotify's Donovan Sung to the folks at TechRadar: "The more we know about you, the better the engine can be. Maybe with motion sensors in phones, we can start guessing things like 'are you running, biking or driving?' Maybe it has a temperature sensor, or a heart rate sensor so we can get a sense of whether you're tense. Maybe it connects to some other services, for example if we know more about your sleeping habits we know what time you're likely to go to sleep or what time you wake up it can be personalised."