Do you bike, hike, ski or perform any activity that involves lots of hills? Did you ever wonder just how much climbing and descending you're doing? If so, Elevation Tracker is for you.

This app uses the iPhone's GPS receiver to track elevation changes, calculates your total climbing and descending as well as your average and maximum gradients, average speed, and distance, and generates an elevation profile, all in real time. You can also connect a Bluetooth heart rate monitor for training zone tracking, and display key info on a Pebble smart watch for quick access during your activities.

When you're done, you can save routes to your history, email route summaries and profile images, send GPX data to other applications, or download refinements from an online elevation database. You can even drag range selectors onto the profile to view the stats for just one section of your route.

The app works in the background or with your device locked, and can run alongside other GPS apps you might be using.

Disclaimer: Continued use of GPS running in the background can dramatically decrease battery life.