Evaluating correctly others’ pain is a crucial prosocial ability, especially relevant for the healthcare system. In clinical settings, caregivers assess their patients’ pain under high workload and fatigue, often while dealing with competing information/tasks. However, the effect played by such cognitive strain in the appraisal of others’ pain remains unclear. Following embodied accounts that posit a shared representational code between self and others’ states, it could be hypothesized that the representation of people’s pain might be influenced by cognitive exertion similarly to first-hand experiences. Fifty participants underwent one of two demanding tasks, involving either working memory (Experiment 1 - N-Back task) or cognitive interference (Experiment 2 - Stroop task). After each task, participants were exposed to painful laser stimulations at three intensity levels (low, medium, high), or video-clips of patients experiencing three intensity levels of pain (low, medium, high). Participants rated the intensity of each pain event on a visual analogue scale. We found that the two tasks influenced rating of both one’s own and others’ pain, by decreasing the sensitivity to medium and high events. This was observed either when comparing the demanding condition to a control (Stroop), or when modelling linearly the difficulty/performance of each depleting task (N-Back). These effects were mirrored by the analysis of physiological responses (Heart Variability and Skin Conductance) evoked by one’s own pain. We provide converging evidence that cognitive exertion affects the subsequent appraisal of one’s own and likewise others’ pain. Healthcare personnel should be aware that high workload might alter their cognitive abilities.