Acute effects of blue and red light exposure on cognitive performance, exercise capacity, perceived effort, and dynamic balance: A randomized crossover study

Abstract

Background: This study investigated the acute effects of narrow-band blue (460 nm) and red (630 nm) light exposure on cognitive performance, exercise capacity, perceived fatigue, and dynamic balance in healthy young males. To our knowledge, this is the first randomized crossover study to systematically assess the combined impact of pre-exercise light exposure on both cognitive-motor integration and aerobic performance within an exercise context. Methods: Fifty physically active young males participated in a randomized crossover design. Participants were exposed to either blue or red light, followed immediately by assessments of simple reaction time (SRT), Incremental Shuttle Walk Test (ISWT) distance, heart rate, perceived exertion, and Y-Balance Test performance. Results: Blue light exposure led to a significant and large improvement in SRT (Δ = −53.33 ms; p < 0.001, η2p = 0.270) and enhanced dynamic balance. Red light exposure produced greater increases in ISWT distance (Δ = +36.98 m; p = 0.004, η2p = 0.453) and significant reductions in perceived fatigue and dyspnea. A moderate positive correlation was observed between SRT improvement and ISWT distance under blue light (β = 0.1869, p = 0.008). Conclusion: This study demonstrates that short-term, wavelength-specific light exposure may optimize both cognitive and physiological readiness prior to exercise. These findings provide novel evidence supporting the integration of individualized light-based strategies in athletic preparation protocols.

Keywords

• Blue light
• Reaction time
• Cross-over studies
• Fatigue
• Postural balance