I use endomondo on my phone to track my distance and speed, but thinking of getting a heart rate monitor - mainly to get an idea of whether I'm pushing myself hard enough or should be trying harder! I'm only doing 5k, but aiming to increase to 10k and thinking a heart rate monitor might be useful in determining how rapidly to increase my efforts. Can anyone recommend a decent one that will work with an iPhone? Or is this a silly reason to use one? And do they tell you what your HR is as you're running or only at the end or can you set it to alarm if it gets to a certain level or something like that?