Members of the medical faculty at the University Dusseldorf investigated whether entire body exposure to visible blue light can decrease blood pressure the same way that UV light is known to do. They also looked at endothelial function (flow-mediated dilation).
They exposed 14 healthy male subjects on 2 days to monochromatic blue light or blue light with a filter foil (control light) over 30 minutes. Then, they measured blood pressure (primary endpoint), heart rate, and endothelial function (flow-mediated dilation), among a list of other things up to two hours after exposure.
They found that exposure to visible blue light significantly decreased systolic blood pressure and increased heart rate as compared to control. Overall, they found that whole body irradiation with visible blue light at real-world doses reduces blood pressure, and improves endothelial function via the release of nitric oxide.
The researchers detailed their findings in the European Journal of Preventative Cardiology.
Stern, M., Broja, M., Sansone, R., et al. Blue light exposure decreases systolic blood pressure, arterial stiffness, and improves endothelial function in humans. European Journal of Preventative Cardiology, Volume: 25 issue: 17, page(s): 1875-1883.