Mac OS X and iOS: Breathing Zone is a simple app that helps slow your breathing rhythm to calm you down and make you feel more relaxed. If you’re a bit stressed or anxious, it’s a good way to help you alleviate those feelings in just a few minutes.
The app works in a very simple way. You set the target number of breaths per minute you want to reach (eight is the default) and Breathing Zone helps you reduce you breathing rate to that number. The app guides you and helps you focus on achieving this goal in five minutes, and this can help you reduce any stress and anxiety you're feeling at the moment. Over time it can even help lower higher blood pressure, and the app is even recommended by the Harvard Medical School. You can pick up a free version for the Mac, but paid versions are available for both Mac and iOS.