This app was mentioned in 5 comments, with an average of 1.00 upvote
Found an option for Android (although doesn't have voice support as that doesn't make sense after having tried in real-time how much your heart rate jumps around and it's difficult to track through audio):
Cardio training (not sure if it's on iOS): https://play.google.com/store/apps/details?id=org.angel.heartmonitorfree.activities&hl=en_GB
Here it the best APP I've found: Cardio Training
Pros:
Cons:
Hey! I was basically in the same spot as you for an app a few months ago, although I also wanted to export to CSV without having to pay $4+. I ended up finding Cardio Training: https://play.google.com/store/apps/details?id=org.angel.heartmonitorfree.activities
Yeah, it's not the prettiest thing ever, but it works for everything you want, I think. I haven't tried the voice coaching/notifications, but that's just my personal taste.
It will tell you some other stuff, but you can also configure the running screen to only display what you want. For instance, I just ignore the kcal count on the save screen.
Seems this app does that. I just installed it and will try it.
https://play.google.com/store/apps/details?id=org.angel.heartmonitorfree.activities Cardio Training