BPM in a smartwatch stands for "Beats Per Minute" and refers to the measurement of the heart rate in beats per minute. A smartwatch can monitor BPM using an optical heart rate sensor that tracks blood flow through the wrist. This feature allows users to monitor their heart rate during various activities, including exercise, sleep, and daily routine. By monitoring BPM, a smartwatch can provide users with insights into their overall health and fitness level. It is important to know the normal range of BPM for a persons age, gender, and fitness level, as any deviations from the normal range can indicate potential health issues. However, its important to note that heart rate can also fluctuate throughout the day and in response to various activities and stressors. Smartwatches can provide users with valuable insights into their health and fitness levels by tracking BPM in real-time.