Evening and bright light
lux / spectrum
Light at the eye in the evening or at night, especially short-wavelength light. Hours outdoors and minutes of scrolling are different clocks.
Melanopsin cells in the retina read how bright the light is and how much blue is in it. The papers assign evening room light, a screen spectrum, or a light-emitting e-reader against print. Morning sun for vitamin D is time outdoors. Time spent on a phone as content is a different clock from the spectrum at the eye.
Also called evening light, blue light, bright light, artificial light at night.
Connected relationships
Randomized trial · Moderate
Evening and bright light→Sleep duration and regularity
Higher Evening and bright light decreases Sleep duration and regularity.
Chang 2015 randomized twelve young adults: five evenings of a light-emitting e-reader versus a printed book delayed dim-light melatonin onset by more than 1.5 hours, suppressed evening melatonin by about 55 percent, and lengthened sleep latency by about ten minutes.
Sources
- AM Chang et al. (2015). Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness.
- G Zerbini et al. (2021). Strategies to decrease social jetlag: Reducing evening blue light advances sleep and melatonin.
- SL Chellappa et al. (2014). Acute exposure to evening blue-enriched light impacts on human sleep.
- N Santhi et al. (2012). The spectral composition of evening light and individual differences in the suppression of melatonin and delay of sleep in humans.
- A Green et al. (2018). Evening light exposure to computer screens disrupts human sleep, biological rhythms, and attention abilities.
- LE Hartstein et al. (2022). High sensitivity of melatonin suppression response to evening light in preschool-aged children.
- MC Gordijn et al. (1999). Effects of light exposure and sleep displacement on dim light melatonin onset.
- L Tähkämö et al. (2020). Systematic review of light exposure impact on human circadian rhythm.