## 1 Introduction
The Monit4 Healthy system was designed specifically to meet these gaps by providing a cohesive and flexible approach that overcomes the present drawbacks of IoT health monitoring technology. Even though several IoT-enabled health monitoring systems have emerged lately, they often face significant shortcomings when it comes to integrating several sensors easily, processing data adaptively, and communicating effectively in real time when resources are limited. Particularly in wearable and portable health monitoring circumstances, high latency, inefficient bandwidth, and increased energy consumption are caused by the inflexible architectures found in several current digital health solutions, such as in cloud-dependent processing and continuous raw data streaming. An extensive number of IoT-based health solutions rely on single-sensor data collection processes and are not sufficiently versatile to provide scaled, context-aware health monitoring in a variety of settings. Section 2, which assesses the current situation of IoT-based health communication technologies and underlines the functional constraints of present systems, provides a detailed analysis of these shortcomings. In order to ensure low-latency communication and interoperability with current digital health infrastructures, adaptive, modular IoT health systems that can perform multi-sensor fusion, structured data transmission, and edge-level signal processing are required. These challenges highlight a clearly defined research gap. As a way to bridge this gap, the digital health solutions must be able to minimize computational overhead and energy consumption while constantly adjusting gathering and transmission techniques in response to the real-time physiological parameters and limitations of the network. In an attempt to swiftly tackle these operational and technological issues, the Monit4 Healthy system was designed and developed. In particular, in environments that demand trustworthy remote management and compatibility with connected health ecosystems, such as smart city healthcare infrastructures, its modular architecture, context-aware signal processing, and structured, event-driven data transmission framework as a whole comprise an alternative and integrated way of advancing IoT-based health monitoring. Thus, the Monit4 Healthy system is a base for future implementations in real-world healthcare and city environments, offering a scalable and adaptable solution to the present drawbacks of IoT health monitoring systems. This paper's remaining sections are organized as follows: Section 2 provides a comprehensive review of IoT-based health communication technologies, focusing on advancements in sensor fusion and real-time biomedical signal processing. Section 3 details the Monit4 Healthy system architecture, covering sensor integration, communication frameworks, and data acquisition processes. Current results are discussed in Section 4, where the system's sensor performance, data transmission efficiency, and overall functional reliability are evaluated. The Monit4 Healthy system's broader impacts are covered in Section 5, which also examines its potential to integrate with smart city infrastructures. Lastly, Section 6 highlights the significance of IoT in forming next-generation healthcare solutions while summarizing significant accomplishments and outlining future research areas.