Improving lighting to reduce sleep and body clock problems during space travel

Melatonin suppression was significantly stronger at 460 nm light compared to 555 nm in a study with 12 subjects.

• Light exposure at 460 nm was found to suppress plasma melatonin more effectively than exposure at 555 nm.
• Equal photon densities of 7.18 x 10(12) photons/cm2/s were used for both light wavelengths during the study.
• An extension of the action spectrum revealed that light at 420 nm also significantly suppressed melatonin at certain intensities.
• The effects of light on melatonin regulation can be monitored through plasma melatonin measurements.

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