Recently, Wireless Body Sensor Networks (WBSNs) have been broadly applied to various healthcare services.Due to their diverse requirements and heterogeneous nature, energy-efficient and battery-friendly communication system is considered as an integral part of WBSNs in this era of energy crises.An essential task is to maximize the energy-efficiency of the nodes in WBSNs as a result of their limited energy resources, continuous recharge from external power sources, small size, lightweight, and fixed energy supply.Furthermore, the replacement or recharging of the battery of the nodes is not always an easy task because it may damage or put the patients life at risk.In an attempt to address these problems, energy-efficient solutions such as, battery driven and Transmission Power Control (TPC) driven methods are proposed in this study.The proposed methods are aimed at addressing the problems of energy consumption and limited battery lifetime of the nodes during communication in WBSNs.It is reported that a significant amount of energy is consumed during communication, which shortens operation and battery lifetime of the nodes for particular applications in WBSNs.Therefore, in this context it is very vital to develop energy-efficient and battery-friendly solutions that can minimize energy-deficiency and extend battery lifetime of WBSNs.A proposed framework of application named medical monitoring of emergency patients through ambulance in remote areas is considered.In this research, a video image of a highly critical conditioned patient in ambulance is taken by built-in cameras in ambulance then sent to a physician in the hospital to diagnose his/her condition.However, video transmission consumes more power due to high peak variable data rates, therefore to address these problems, energy-efficient and battery-friendly algorithms must be developed in WBSNs.Furthermore, energy hungry video transmission process and slow progress in battery technologies have become major problems in WBSNs.The main challenges addressed in this research are to minimize energy drain, battery charge consumption, and extend the battery lifetime of the nodes during Variable Bit Rate (VBR) video and vital sign signals (i.e.12-lead electrocardiogram) transmissions in WBSNs.To overcome these problems, sustainable and energy-efficient approaches such as, Lazy Video Transmission Algorithm (LVTA) and Video Transmission Control Algorithm (VTRCA) are proposed with analytical battery model.These algorithms potentially minimized energy consumption during transmission, battery charge consumption and high peak load current profile.The LVTA and VTRCA enhance energy-efficiency and the lifetime of nodes where energy-efficient and prolonged video transmission occurs.The simulation results demonstrate that LVTA and VTRCA improve the energy-efficiency and battery lifetime of the WBSNs up to 49.49％, 47.8％ and 1.18％, 19.8％, accordingly.Moreover, due to large temporal variations in the wireless on-body channel, typical conventional techniques do not provide the sufficient energy saving in WBSNs.To overcome this problem an energy-efficient transmission solution with TPC that adaptively adjusts transmission power (TP) level based on the feedback from base station is proposed.The main advantages of the proposed algorithm are more energy-efficiency with acceptable packet loss ratio (PLR) and lower complexity.An average transmission power is used while the required parameters are optimized and analyzed for the enhancement of the systems performance.The proposed algorithm achieved significantly higher energy savings of 40.9％, which is demonstrated by Monte Carlo simulations in MATLAB.However, a limitation of proposed algorithm is a slightly higher PLR value in comparison to the conventional TPC such as, constant transmission power and the methods proposed by Gao and Xiao.The methods proposed in this study are valid for two different cases i.e., energy consumption due to high peak variable rates, high transmission power consumption, and dynamic nature of wireless channel.Each method is categorized for separate applications.First method focuses on constant transmission power level and high variable data rates such as, medical monitoring of emergency patients while the second method concentrates on driving the system towards the highest possible transmission power level and constant rate such as, physiological parameters (i.e.12-lead ECG) respectively for patients in WBSNs.To conclude this research, a comparison of LVTA, VTRCA, and TPC algorithms is performed.Obtained results reveals that the average current in milli amperes and the average data rate in bits per sec at the transmitter node determine the energy-efficiency of the proposed algorithms.These simulation results show that LVTA and VTRCA save more energy of 49.49％ and 47.8％,respectively than TPC algorithm which saves energy of 40.9％ in WBSNs.