Here is a brief overview of the different sensors and heart rate monitors (HRM) that Garmin currently offers (March 2019), to make it easy for you to choose which one is right for you.
For more detailed information please have a look here:
- All about the Garmin Running Dynamics Pod – https://www.dcrainmaker.com/2017/03/garmins-running-dynamics-pod-rd-pod-everything-you-ever-wanted-to-know.html
- Introduction to Garmin running dynamics – https://www.rizknows.com/garmin-physiological-features/
- EVERYTHING about Physiological Measurements and Running Dynamics https://www.garmin.com/en-US/performance-data/running/
- Review of Garmin HRM-Tri and HRM-Swim – https://www.dcrainmaker.com/2015/11/garmin-hrm-swimtri-review.html