Work overload is a significant source of stress in the workplace. Recent research suggests that 9.8% of the world’s population is overworked, and that the percentage of overworked individuals is rising annually. In this context, work overload has been extensively studied in both practice and academia, but yield conflicting conclusions. From a practical standpoint, a survey of 11,024 employees conducted by ZhaoPin, a well-known Chinese recruitment service platform, indicates that employees comprehend work overload in terms of trade-offs and view the overpayment of work overload in relation to its excess return. Nearly 30% of respondents believe that the difficulty of work overload is proportional to the benefit, and they have a favorable attitude towards it. However, past studies have mostly viewed work overload from a stress viewpoint, concentrating primarily on the losses employees experience as a result of work overload, and there are inconsistent research findings. In fact, the future excess returns of work overload are frequently unknown, which can further complicate employee responses to work overload, yet previous research has not fully elucidated the complicated psychological underpinnings of people experiencing work stress. Based on this, the present study investigates, from an exchange viewpoint, the mechanisms behind employees' responses to work overload. Present study focuses on the dyadic exchange relationship between leader and member and investigates the double-edged sword effect of work overload resulting from perceived development practice path and perceived leader exploitation, as well as the moderate effect of leader-member exchange (LMX). Two sub-studies were conducted in this research. In Study 1, we administered a three-wave time lag survey to 400 employees from several companies of Guangdong, Hunan, and Gansu provinces, with each period separated by 15 days, and 293 matched questionnaires were finally returned. In Study 2, a total of 220 working employees were recruited to participate in an experiment between groups, and 199 respondents passed the attention test in the end experiment. The results of a three-period survey and a scenario-based experiment indicate that work overload has a dual effect. The findings of a combined three-period time-lag survey of 293 current employees (Study 1) and a between-group experiment with 199 current employees (Study 2) indicate that work overload has a double-edged sword effect. On the one hand, work overload influences turnover intentions positively through perceived exploitation; on the other hand, work overload positively influences work effort and negatively influences turnover intentions through perceived employee development practices. Moreover, leader-member exchange (LMX) moderates this double-edged sword effect. Compared to employees with low LMX, employees with high LMX are more likely to view leader-induced work overload as an employee development practice, as opposed to exploitation, and are consequently more likely to increase their work effort and decrease their turnover intentions. This research has three primary contributions. First, while previous studies have focused on the loss of work overload from a stress perspective, this study addresses the future excess rewards of work overload (e.g., promotion signals) based on an exchange perspective and reveals the mechanism of positive employee responses to work overload from the perspective of perceived employee development practices. In addition, this research combines the reciprocity principle of social exchange to fully explain the ambivalence and dual response mechanisms of employees facing work overload as a result of the contrast between the immediate excess resource loss of work overload and the uncertain future excess gain, thereby enhancing the work overload research. Second, when analyzing the boundary conditions of employees' responses to work overload, past research mainly focused on static factors such as individual personality traits. This study proposes that LMX is an important boundary condition for employees to assess work overload, hence enhancing exchange-based research on work overload. Finally, this study reveals the negative exchange mechanism between leader and member from the perspective of perceived exploitation, which complements the lack of attention to negative exchange in prior leader-member exchange investigations. From a practical standpoint, this study's findings enable managers and employees to take a more dialectical view of work overload and build on their strengths and avoid their weaknesses.