This study aims to investigate the effect of exoskeletons on workers’ cognitive processing during hazard identification tasks after physically demanding construction lifting tasks. To do so, a within-subject experiment was designed with 10 participants. They completed hazard identification tasks for various construction scenarios before and after performing lifting tasks for a specified duration, both with and without the exoskeleton. Brain activities in left and right dorsal prefrontal cortex (DLPFC) were measured and functional connectivity of the area was conducted using functional near-infrared spectroscopy (fNIRS). The results indicated significantly higher DLPFC activation during the cognitive tasks post-lifting with an exoskeleton (p = 0.013 < 0.05) compared to the same activity without an exoskeleton. The finding suggests that wearing exoskeletons could enhance cognitive processing and hazard identification performance by mitigating both physical exertion and mental load. This study provides valuable insights into the benefits of exoskeletons in construction settings, highlighting their potential to reduce fatigue-related cognitive decline and improve overall safety performance.