I have started testing Beddit device and it does track Heart rate while you rest or sleep.
I find it interesting because the sensor in on your bed, you don't feel it.
Measurement is automated and captured in the online app.
I have attached screen shot of the heart rate graph in this post.
Let me know if I should share more about this solution in case you have questions. It will also help me learn at the same time possibilities offered by Beddit and other solution for sleep tracking.
When you collect more sleep data, you can of course start have some graphs like the one I just attached. I just discovered it in the Beddit online tracker where my data is compiled.
I feel I do not have yet enough experience and data collected but believe I can learn more after I return from holidays.
Any other screen capture of tracking tools members are using ?