BPM Music allows you to select and stream Music for your requested BPM when you are for example in the gym or running outside... You need a Premium Spotify account for this app!
Heart rate, or heart pulse, is the speed of the heartbeat measured by the number of heartbeats per unit of time — typically beats per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excrete carbon dioxide.
First, you need to decide what BPM you are looking for and what kind of run this is. For example:
*** 5k - very fast run, need high BPM songs for the whole time, and a short playlist (since it usually doesn't take more than 40 minutes to finish).
*** Marathon - very slow run, you need mostly low BPM songs but not too low (in the 120-130 range and maybe a few higher ones to boost morale), and a very long list.
Once you know your target BPM, you can easely use BPM Music with your spotify account to select and play songs for that BPM.