The effects of coherent breathing and blue light after an acute stress on sleepiness and the stress response in a workplace setting: A randomized double-blind cross-over trial

This study evaluates the effectiveness of an innovative tertiary stress management intervention for workplace application, combining 0.1 Hz coherent breathing with blue light exposure via the ÉOS device. We hypothesize that the intervention can mitigate acute stress reactions and sleepiness more effectively than passive rest without external stimulation. Using a randomized-controlled crossover double-blind design in a workplace-based laboratory setting, we assessed the effect of an intervention following exposition to Maastricht Acute Stress Test in 29 individuals. Subjective stress (single item scale), sleepiness (Karolinska Sleepiness Scale), positive and negative affect (Positive and Negative Affect Schedule), along with heart rate variability (HRV) and electroencephalography metrics were evaluated using linear mixed-effect models. The intervention significantly reduced subjective stress by 31.23% (CI 21.41% and 41.83%), decreased sleepiness by 0.84 points (SE 0.17), and increased positive affect by 1.85 points (SE 0.54). No significant effect was found on negative affect, HRV, frontal alpha asymmetry or theta/beta ratio. The findings suggest that combining coherent breathing with blue light exposure effectively reduces acute stress and enhances mood without causing sleepiness, making it a promising workplace stress intervention. This study contributes to stress management research by demonstrating the potential of these tertiary stress management interventions to improve well-being and performance in occupational settings. Future research should evaluate the individual effects of each component, examine long-term outcomes, and include diverse populations to strengthen these findings.