Light Therapy for Circadian Rhythm Sleep Disorders

 Light therapy or phototherapy has been found to be an effective treatment for Delayed Circadian Rhythm Sleep Disorder. It has been reported by Takahashi et al, that the circadian pacemaker could be reset by as much as 12 hours  by appropriately timed exposure to bright light and darkness.

 People who experience delayed sleep disorder have a circadian pacemaker which runs at a slower than normal pace, sleep onset is delayed, they may have difficulty falling asleep as well as maintaining sleep. They usually prefer to stay up late and enjoy the night hours, an unfortunate consequence of this is difficulty waking at what is considered to be appropriate time the following morning.

The sleep/wake cycle is regulated by a control center located in the hypothalamus area of the brain known as the suprachaismatic nucleus, this is the location of the circadian pacemaker . This body clock responds to both endogenous and exogenous signals, exogenous signals or zeitgebers include bright light particularly sunshine, darkness, sounds, and other external stimuli which are usually associated with certain times of the day. The internal pacemaker depends on these signals to trigger response to the sleep/wake cycle, without these external cues, such as occur with patients in ICU settings where the time cues are absent or minimal, circadian rhythm sleep disorders are common.

The dawn simulator sends an appropriately timed light stimulus to the retina of the eye, then on to the suprachaismatic nucleus located in the hypothalamus.The dawn simulator does exactly that, it behaves like a slowly rising sun, the light intensity increases slowly so that waking is a gradual process.

Light therapy in the form of dawn simulators offer a solution for people who have delayed circadian rhythm sleep disorder, they provide the external cue necessary to trigger waking. DCRS sufferers have a pineal gland which is in slow mode, the pineal gland which secretes melatonin does so in a manner which results in late sleep onset, and difficulty in morning waking.

The dawn simulator causes the pineal gland to readjust to a new time slot, causing you to wake to a new day feeling refreshed and alert, thus providing an ideal, simple and healthy solution to delayed circadian rhythm sleep disorder.

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