Interval Trainer with Heart Rate Monitor is a simple, effective timer for HIIT (High Intensity Interval Training) workouts.

Please note, you'll need an Apple Watch to track your heart rate as the iPhone cannot do this by itself.

The Interval Trainer Apple Watch app integrates with Apple's Health App. If you use Interval Trainer with your Apple Watch, Interval Trainer will track your heart rate as well as total calories burned during your workout. After tapping "End Workout" on your Apple Watch, you will be given the option to either save your workout data to the Health app or discard it. Interval Trainer does not integrate with the Health app if you do not use Apple Watch to track your workout.

I created this app because I wanted gentle alerts telling me when it was time to switch between "Push" and "Recover" during my HIIT workouts while I listened to music on my iPhone. This app accomplishes this in two ways:

1) If you use Interval Trainer on an iPhone while listening to music, the app will briefly lower the volume of your music while it plays a clap sound effect when it is time to switch.

2) If you use Interval Trainer on an Apple Watch with the watch on silent, you'll get a notification vibration two seconds before it's time to switch and another notification vibration when it is time to switch. The reason for two notifications is because with one notification sometimes I wasn't sure if I really felt it. Two notifications takes away the guesswork.

A note to Apple Watch users: In order for Interval Trainer to keep working when your watch screen goes off, the app needs to create a workout session. Your watch can only have one workout session going at a time. This means you can't use Apple's Workout app at the same time as Interval Trainer. My favorite thing about Apple's Workout app is that it shows me my heart rate during workouts. That's why I included the heart rate monitor in Interval Trainer. Now I don't miss not being able to use Apple's workout app while I use Interval Trainer. Additionally, Interval Trainer provides you the option to either save or discard your workout data at the conclusion of your workout. Save it if you want it to count towards your activity rings and be saved in Apple's Health app.

I hope you enjoy using Interval Trainer with Heart Rate Monitor.

Please don't hesitate to contact me if there is anything I do to improve your experience. Just tap the "Feedback" button in the app's Settings.

Now go get sweaty!
Justin