Innovative approaches to remote patient monitoring have been developed as a result of the adoption of Internet of Things (IoT) technology in the healthcare industry. An example of such an application is the Internet of Things (IoT)-based heart rate monitoring system, which permits continuous and instantaneous heart rate monitoring. In-depth reviews of IoT-based heart rate monitoring systems are provided in this study, together with information on the underlying technologies, architectural frameworks, difficulties, and potential paths for further research. In the design and implementation of these systems, the review emphasises the significance of wearable sensors, communication protocols, data processing methods, and user interfaces. The benefits and drawbacks of certain architectural frameworks, such as distributed and hierarchical structures, are covered. Additionally, the article lists important issues such data security, accuracy, and interoperability and suggests possible fixes to deal with them. An infrared light-emitting diode (IR LED) and a photo diode make up the sensor unit. An infrared light is transmitted into the fingertip by the IR LED, some of which is reflected. from the blood within the arteries in the fingers. The percentage of light that is reflected back is detected by the photodiode. The amount of blood in the fingertip determines how much light is reflected. Thus, the photo diode can detect changes in the amount of reflected infrared light caused by heartbeats. This slight change in the reflected light's amplitude can be transformed into a pulse using a high gain amplifier.