Annals of the Academy of Medicine, SingaporeSep 18, 2008

Using light to treat sleep problems caused by body clock disorders

Circadian Biology Weekly Brief ↗PubMed ↗

Updated Apr 2, 2026

Abstract

Bright light therapy is established as an effective treatment for sleep-wake and circadian misalignment.

Circadian rhythm sleep disorders can lead to insomnia, fatigue, and decreased performance due to misalignment with the external environment.
Exposure to bright light at appropriate times may reset sleep and wake patterns, enhancing sleep quality and daytime alertness.
The effectiveness of bright light therapy is influenced by the timing of light exposure within the circadian cycle.
Bright light therapy can be applied to various conditions, including advanced and delayed sleep-phase disorder, free-running disorder, shiftwork disorder, and jet lag.
Guidelines for the safe use and timing of bright light therapy are discussed based on laboratory and field studies.

Simplified

The human circadian system is normally synchronised with the solar day, insuring that alertness and performance peak during daytime hours and consolidated sleep occurs during the night. In circadian rhythm sleep disorders, the pattern of sleep-wake is misaligned with the patient's circadian system or the external environment, resulting in insomnia, fatigue, and deterioration in performance. Appropriately-timed exposure to bright light can reset the timing of sleep and wake to the desired times, and improve sleep quality and daytime alertness. The efficacy of bright light therapy, however, is dependent on the time-of-day of the circadian cycle that the light is administered. In this article, we examine the physiological basis for bright light therapy, and we discuss the application of light in the treatment of circadian rhythm sleep disorders including advanced and delayed sleep-phase disorder, free-running disorder (nonentrained type), shiftwork disorder and jet lag disorder. We review the laboratory and field studies which have established bright light therapy as an effective treatment for sleep-wake and circadian misalignment, and we also provide guidelines for the appropriate timing and safe use of bright light therapy.

Using light to treat sleep problems caused by body clock disorders

Abstract

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

Abstract

Related papers

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