Over the past few decades, there has been a revolution in ICT, and this has led to the evolution of wireless sensor networks(WSN), in particular, wireless body area networks. Such networks comprise a specialized collection of sensor nodes(SNs) that may be deployed randomly in a body area network to collect data from the human body. In a health monitoring system, it may be essential to maintain constant environmental conditions within a specific area in the hospital. In this paper, we propose a temperature-monitoring system and describe a case study of a health-monitoring system for patents critically ill with the same disease and in the same environment. We propose Enhanced LEACH Selective Cluster(E-LEACH-SC) routing protocol for monitoring the temperature of an area in a hospital. We modified existing Selective Cluster LEACH protocol by using a fixed-distance-based threshold to divide the coverage region in two subregions. Direct data transmission and selective cluster-based data transmission approaches were used to provide short-range and long-distance coverage for the collection of data from the body of ill patients. Extensive simulations were run by varying the ratio of node densities of the two subregions in the health-monitoring system. Last Node Alive(LNA), which is a measure of network lifespan, was the parameter for evaluating the performance of the proposed scheme. The simulation results show that the proposed scheme significantly increases network lifespan compared with traditional LEACH and LEACH-SC protocols, which by themselves improve the overall performance of the health-monitoring system. Over the past few decades, there has been a revolution in ICT, and this has led to the evolution of wireless sensor networks (WSN), in particular, wireless body area networks. Such networks include a specialized collection of sensor nodes (SNs) that In a health monitoring system, it may be essential to maintain constant environmental environmental conditions within a specific area in the hospital. In this paper, we propose a temperature-monitoring system and describe a case study of a health-monitoring system for patents critically ill with the same disease and in the same environment. We propose Enhanced LEACH Selective Cluster (E-LEACH-SC) routing protocol for monitoring the temperature of an area in a hospital. We modified existing LEACH protocol by using a fixed-distance-based threshold to divide the coverage region in two subregions. Direct data transmission and selective cluster-based data tran smission approaches were used to provide short-range and long-distance coverage for the collection of data from the body of ill patients. Extensive simulations were run by varying the ratio of node densities of the two subregions in the health-monitoring system. Alive (LNA), which is a measure of network lifespan, was the parameter for evaluating the performance of the proposed scheme. The simulation results show that the proposed scheme significant increases network lifespan compared with traditional LEACH and LEACH-SC protocols, which by themselves improve the overall performance of the health-monitoring system.