Breathing slowly can help calm and relax you and help to remove stress.
This app is based on a 4 second in breath with a 6 second out breath.
Set the timer for how long you want to practice.
If your device supports vibration, you can use this alongside or instead of the audible alerts. Just tap the sound and vibration icons to turn them on and off.
You can set the timer to automatically repeat if you want to hear a tone between poses/exercises you might be doing.