Reducing Test Anxiety: A Randomized Controlled Pilot Study of Evening Bright Light Exposure in University Students

Background: University students often experience high levels of stress and anxiety during exam periods, adversely affecting their well-being and academic performance. This study investigated the short-term effects of evening bright light (BL) exposure on several psychophysiological stress measures during exam preparation. Methods: In this preregistered randomized controlled pilot study, 35 university students were assigned either to an intervention group exposed to BL (1500 lx, 4000 K; n = 18) or a control light (CL) group with standard lighting (100 lx, 3000 K; n = 17) for 4 h over five consecutive evenings. Outcomes included questionnaires (test anxiety, general anxiety, psychological distress), cognitive performance (2-back, go-/no-go task [GNT]), physiological stress (heart rate variability [HRV]), and subjective and objective sleep quality measures (actigraphy). Results: The BL group showed significant reductions in test anxiety by the last evening. Both groups improved in working memory performance over time. HRV analysis revealed mixed results, with some indications of reduced stress in the BL group on the first day. No adverse effects of evening BL were found on sleep parameters, and participants reported significantly higher satisfaction with the BL exposure. Conclusions: Evening BL exposure during exam preparation may help reduce test anxiety without significantly disrupting sleep. Although cognitive performance effects were limited, the perceived usefulness suggests that BL could be a well-accepted supportive measure for students during stressful academic periods. Further research is needed to optimize light-based interventions for student well-being.