Blue light can significantly reduce blood pressure Blue light exposure significantly decreased systolic blood pressure and increased heart rate as compared to control. In parallel, blue light significantly increased forearm blood flow, flow-mediated dilation, circulating nitric oxide species and nitroso compounds while it decreased forearm vascular resistance and pulse wave velocity Manuel Stern, Melanie Broja, Roberto Sansone, Michael Gröne, Simon S Skene, Joerg Liebmann, Christoph V Suschek, Matthias Born, Malte Kelm, Christian Heiss. Blue light exposure decreases systolic blood pressure, arterial stiffness, and improves endothelial function in humans. European Journal of Preventive Cardiology, 2018; 204748731880007 DOI: 10.1177/2047487318800072