PurposeAt the dawn of a new decade, as ever more corporations are pursuing sustainable working conditions and advocating employee well-being, employees are increasingly tending to feel fatigued and drained by their work, which compromises their performance. Drawing on the job demands–resources model and social acceleration debate, the authors test a moderated mediation model. Specifically, the authors hypothesise that unreasonable tasks raise perceptions of emotional exhaustion when the pace of work is increased and investigate the moderating role of psychological detachment.Design/methodology/approachThis study used a sample of 245 employees from Europe, all knowledge workers, to test the hypotheses.FindingsApart from unreasonable tasks being directly related with emotional exhaustion, this relationship was mediated by the perceived work pace. In addition, the authors establish psychological detachment as a relevant moderator for the mediating effect.Practical implicationsManagers and HR practitioners are equipped with a better understanding of the effects of an increasing speed of work, the conditions leading to it and the individual and organizational resources that may help to create healthy and meaningful job positions, which facilitate employee efficiency.Originality/valueOur study expands the literature on contemporary stressors and adds to what is known about the ‘dark side’ of job demands that affect the organizational bottom-line, as well as the resource-based mechanism that can buffer the negative effects.