The European journal of neuroscienceDec 4, 2018

Reducing evening blue light helps shift sleep and melatonin earlier to lower social jetlag

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Mar 25, 2026

Abstract

Decreasing evening blue light exposure led to an advance in melatonin and sleep onset on workdays.

Circadian rhythms are influenced by a combination of genetic, physiological, and environmental factors, resulting in individual differences in sleep timing.
Social jetlag occurs when there is a mismatch between the body's circadian clock and societal obligations, leading to irregular sleep patterns and accumulated sleep debt.
Interventions aimed at reducing social jetlag included decreasing evening light exposure with blue-light-blocking glasses and increasing morning light exposure using curtains.
While decreasing evening blue light exposure advanced melatonin secretion and sleep onset, increasing morning light exposure did not significantly affect these measures.
Neither intervention resulted in a significant change in the extent of social jetlag, but evening light management may assist late chronotypes in adjusting to early schedules.

Simplified

The timing of sleep is under the control of the circadian clock, which uses light to entrain to the external light-dark cycle. A combination of genetic, physiological and environmental factors produces individual differences in chronotype (entrained phase as manifest in sleep timing). A mismatch between circadian and societal (e.g., work) clocks leads to a condition called social jetlag, which is characterized by changing sleep times over work and free days and accumulation of sleep debt. Social jetlag, which is prevalent in late chronotypes, has been related to several health issues. One way to reduce social jetlag would be to advance the circadian clock via modifications of the light environment. We thus performed two intervention field studies to describe methods for decreasing social jetlag. One study decreased evening light exposure (via blue-light-blocking glasses) and the other used increased morning light (via the use of curtains). We measured behaviour as well as melatonin; the latter in order to validate that behaviour was consistent with this neuroendocrinological phase marker of the circadian clock. We found that a decrease in evening blue light exposure led to an advance in melatonin and sleep onset on workdays. Increased morning light exposure advanced neither melatonin secretion nor sleep timing. Neither protocol led to a significant change in social jetlag. Despite this, our findings show that controlling light exposure at home can be effective in advancing melatonin secretion and sleep, thereby helping late chronotypes to better cope with early social schedules.

Full Text

Full text is available at the source.

View Full Text ↗

Reducing evening blue light helps shift sleep and melatonin earlier to lower social jetlag

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

What Lands in Your Inbox Each Week:

Recent issues from the circadian biology brief