"An average resting heart rate is between 60 to 100 beats each minute.
Because medication may affect your heart rate, it’s important to check with your health care provider before starting an exercise routine."
https://www.allinahealth.org/healthysetgo/move/why-you-should-monitor-your-exercise-heart-rate
"Heart rate is important because the heart's function is so important. The heart circulates oxygen and nutrient-rich blood throughout the body. When it's not working properly, just about everything is affected. Heart rate is central to this process because the function of the heart (called "cardiac output") is directly related to heart rate and stroke volume (the amount of blood pumped out with each beat)."
https://www.health.harvard.edu/heart-health/hows-your-heart-rate-and-why-it-matters
"Heart rate monitors are devices that can detect and track your heart or pulse rate continuously. Most of these devices are wearable, and many are highly accurate. While these devices can be valuable tools in monitoring your health, they aren't as accurate as approved medical devices, and you shouldn’t use them in place of medical care."
https://my.clevelandclinic.org/health/diagnostics/23429-heart-rate-monitor
"A cardiac monitoring device is a small gadget prescribed by the doctor/physician to monitor a patient’s heart condition from a distance, remotely. The device is so small that it can be easily carried in the front pocket of the shirt (preferably near the heart) or taped on the chest. It is then connected to a mobile app through Bluetooth or BLE.
Advanced technology enables the device to catch even the smallest possible sounds and aberrations in the heartbeat. These small anomalies and irregularities are called heart arrhythmias. If the arrhythmias occur consistently, there is a problem in the heart and medical help is needed."
https://bacancysystems.com/blog/importance-of-cardiac-monitoring-devices