Organisms are cued by the 24-hour light dark cycle, which is built into their biological processes and acts in magnitude as a paramount influence on human behaviour (Chellapa, Godijn & Cajochen, 2011). Light is something we take for granted, yet it is closely linked to our behaviour, endocrines, pulse rate, alertness, mood, performance, vasoconstriction or vasodilation, body temperature and gene expression (Beaven & Ekström, 2013; Chellapa et al., 2011). Blue light therapy is used to mimic morning daylight which encourages the body and brain to awaken (Gabel et al., 2013).
Vandewalle et al. (2013) have revealed through functional magnetic resonance imaging (fMRI) that even blind individuals can respond to light. Their study involved an auditory working memory task; what they found was that just one minute of blue light therapy led to increased activity in the prefrontal and thalamic cortices, which are brain regions involved in alertness and cognitive regulation (Vandewalle et al., 2013). Gabel et al. (2013) note that light interacts with the suprachiasmatic nucleus (SCN), the brain region responsible for regulating our circadian rhythm, which is then able to modulate and influence the neural activity in widespread brain regions (Gabel et al., 2013). This overarching brain activation creates the wakefulness state that we are all accustomed to.
Benefits and Effects
Short-wavelength light such as blue light (460-nm) has been found to decrease subjective sleepiness, improve attentional capacity and vigilance and lower EEG wavelength density in the delta-theta frequency, which are wavelengths associated with sleep (Chellapa et al., 2011; Lehrl et al., 2007). Numerous studies have shown the ability of blue light therapy to induce wakefulness, further promote improved cognitive performance, mood, and subjective-wellbeing as well as reduce stress (Beaven & Ekström, 2013; Chellappa et al., 2011; Ekström & Beaven, 2014; Gabel et al., 2013; Lehrl et al., 2007; Vandewalle et al., 2013). Gabel et al. (2013), noted that blue light therapy does not replace sleep quality, as the benefits of this short-wavelength light are less pronounced with increased sleep restriction.
According to Gabel et al. (2013), to produce optimal and lasting changes in cognitive performance throughout your day, you may introduce 30 minutes of blue light, gradually increasing in intensity followed by 20 minutes of moderate intensity, for a total of 50 minutes. Chellappa et al. (2011) note that only 1 minute of light exposure can produce benefits in cognition for up to 20 minutes.
Beaven, C. M., & Ekström, J. (2013). A comparison of blue light and caffeine effects on cognitive function and alertness in humans. PloS one, 8(10), e76707. DOI: 10.1371/journal.pone.0076707
Chellappa, S. L., Gordijn, M. C., & Cajochen, C. (2011). Can light make us bright? Effects of light on cognition and sleep. In Progress in brain research (Vol. 190, pp. 119-133). Elsevier.
Ekström, J. G., & Beaven, C. M. (2014). Effects of blue light and caffeine on mood. Psychopharmacology, 231(18), 3677-3683. DOI: 10.1007/s00213-014-3503-8
Gabel, V., Maire, M., Reichert, C. F., Chellappa, S. L., Schmidt, C., Hommes, V., … & Cajochen, C. (2013). Effects of artificial dawn and morning blue light on daytime cognitive performance, well-being, cortisol and melatonin levels. Chronobiology international, 30(8), 988-997. DOI: DOI: 10.3109/07420528.2013.793196
Lehrl, S., Gerstmeyer, K., Jacob, J. H., Frieling, H., Henkel, A. W., Meyrer, R., … & Bleich, S. (2007). Blue light improves cognitive performance. Journal of neural transmission, 114(4), 457-460. DOI: 10.1007/s00702-006-0621-4
Vandewalle, G., Collignon, O., Hull, J. T., Daneault, V., Albouy, G., Lepore, F., … & Lockley, S. W. (2013). Blue light stimulates cognitive brain activity in visually blind individuals. Journal of cognitive neuroscience, 25(12), 2072-2085. DOI: 10.1162/jocn_a_00450