You have to convert the audio to a bluetooth compatible codec like LDAC instead of just using the audio file which is in a format like mp3 with a higher bitrate. Compressing the signal can make the audio sound worse. (I would say bluetooth makes it sound worse for most situations but by how much is somewhat of an opinion question)
I think the results below might say that faster walkers tend to be at a healthier weight. Better lipid panels and less inflammation probably means fewer are overweight and obese.