Spotify used all my battery in around an hour. Phone also got very hot.

[Craigski]

I just noticed my phone getting very hot in my pocket.  Pulled it out to find Spotify had reduced my phone from 100% to under 10% with just over an hour of streaming.  Quick visit to the battery settings showed Spotify had used a large percentage in background activity.  Unfortunately I hadn't reset my data stats for some time so I can't tell for sure if it was also pulling down large amounts of data in the same period.

Does anyone have any suggestions for troubleshooting I should be doing?  I've rebooted the phone and it seems fine now with streaming.