Knowing your current heart rate is useful, but seeing in real time how it varies over a longer period gives you much more information, especially when trying to understand how your body is responding to a training plan. Heart Graph can be used for all types of aerobic exercise including running, cycling, rowing or gym work, and of course you can also use it to study your normal heart rate for general health reasons.

Heart Graph allows you to record new data and see your heart rate graph in real time, as well as importing existing data from Apple Health. Data from previous sessions can then be compared to give a deeper understanding of how your body is changing over time, for example by directly comparing the graphs for equivalent sessions, viewing statistics such as max, mean and resting heart rate across sessions, or seeing the proportion of time spent in different heart rate zones aggregated over weeks or months. (Note some features require a one-off In-App Purchase, as described below.)

FREE features of Heart Graph include:
* Display a real-time graph of heart rate against time on your iPhone or iPad
* Support for both Bluetooth sensors and Apple Watch
* No ads
* Review your sessions offline to spot trends in your data
* Integration with Apple Health: import existing workout data and store new workouts
* Maximise the screen area for graphs on iPhone using landscape orientation
* Group related sessions by adding your own notes, then searching for sessions matching those notes
* Record a standard Reference Set at the start of each session to help determine how your body is really doing; if your heart rate is elevated, you may want to take it easy
* Record data in the background if you want to use other heart rate apps (Bluetooth sensors)
* Calculate calories burned, and set a calorie target for each session

Beyond the basics, a single, one-off In-App Purchase will enable the Premium Features, giving you access to more in-depth analysis tools and the ability to design your training sessions in the app. These Planned Workouts split a session into small pieces, for example sets at the the gym, or intervals on a bike. When you’re exercising, Heart Graph will keep track of where you are in the session and what’s coming up next, alerting you when it’s time to stop or move on. The trigger for moving from one set to the next can be a simple time gap (“wait 30 seconds”), or be based on heart rate to allow a specific amount of recovery before continuing (“wait until heart rate is below 120bpm”). The outcome is a structured plan that adapts to how your body is responding each time you do that session.

Premium Features include:
* View and analyse the time spent in each of five configurable heart rate zones
* Add annotations to the graph during recording to help identify key events
* Heart rate alarms when your heart rate changes zone or goes above or below configurable thresholds
* Import data from the Health app for custom time periods of up to 24 hours
* Directly compare graphs for equivalent sessions
* Compare statistics (such as max, mean and resting heart rate) across sessions
* Record a session to explicitly measure resting heart rate while you relax
* Audio rep counting so you never lose count - make a noise every time you complete a rep and the app keeps track of how many you’ve done
* Import and export heart rate data from other apps or your computer using Garmin TCX format files
* Import Garmin GPX format files
* Export data to CSV files for further analysis in software such as Excel (email, Dropbox, etc)

Heart Graph requires an external sensor to record heart rate, such as:
* A bluetooth (BTLE) sensor such as the Wahoo Tickr / Polar H10 chest straps, or the Mio Alpha watch
* An Apple Watch
* An ANT+ sensor connected using the Wahoo Key

DISCLAIMER: Heart Graph is not a medical device, and you must always seek a doctor’s advice before making any medical decisions.