Biological Rhythms and the Body Clock - Part I:

The Basis of Light Therapy for Sleep Disorders

In all mammals, including humans, there is a "body clock" in the brain that coordinates the daily (circadian) rhythms that the body experiences throughout the day. These rhythms include the cycle of waking and sleeping, the rise and fall of blood pressure and heart rate, and daily rhythms of gastrointestinal, renal, and immune system activity.

The body clock aligns its timing to the external environment through exposure to light. In mammals the pathway through which the environmental light signal enters the brain originates in the retina of the eye. While this pathway evolved to be sensitive to sunlight, artificial light of an appropriate form can also be used. With the normal polychromatic (white) light normally used for indoor lighting, very high intensities of light are needed to regulate human circadian rhythms.

The "body clock" in the brain usually does not have a period of exactly 24 hours. It re-aligns itself to the external pattern of night and day on a daily basis through exposure to sunlight. Light therapy can be used to synchronize sleep patterns in a manner similar to the way sunlight normally synchronizes the "body clock". If the clock is stimulated by light before it expects the sun to have risen, it will reset to an earlier time. If stimulated by light after the time it expects the sun to have set, the body clock will reset itself to a later time. Ref

It was originally thought that exposure to very bright visible light is needed to influence brain physiology and reset the human body clock. It has been confirmed that the most effective wavelengths of visible light are those identified when GreenLIGHT technology used in Lo-LIGHT lamps was patented. Independent studies from laboratories around the world and published in highly rated, peer-reviewed journals have found that Sunnex Biotechnologies' low-intensity light therapy technology influences the body clock as effectively as bright light, but in a safer and more comfortable manner. More on regulation of the body clock by light exposure.

Light therapy can be used to correct sleep phase disorders, which occur when a person's internal biological clock is delayed or advanced from the external environment. Delayed Sleep Phase Syndrome (DSPS), which often begins at a young age, makes it difficult to fall asleep until the early morning hours. Ref People with Advanced Sleep Phase Syndrome (ASPS), which usually starts later in life, tend to become tired in the afternoon or early evening, and then find themselves wide awake in the middle of the night. More on aging, and how it affects the body clock.

Light therapy for people with delayed sleep phase disorder -DSPS

For people with a delayed circadian rhythm, the internal biological clock can often be shifted to an earlier position and aligned with the external environment through exposure to appropriately timed light therapy in the morning. Similarly, for people whose internal clocks are set too early, the internal clock can be often shifted to a later position with evening light therapy. Refs However, the timing of light treatment with respect to the position of the internal clock is critical. People with delayed or advanced sleep phase syndromes would be well advised to consult with a qualified sleep therapist before embarking on a program of light therapy.

The insight by Sunnex Biotechnologies scientists 2 decades ago that wavelength is as important as intensity for shifting the body clock has now been confirmed by research groups around the world. Independent university and military laboratories have also confirmed that the most efficient wavelengths for shifting the body clock are provided by the patented Sunnex Biotechnologies low-intensity GreenLIGHT technology used in Lo-LIGHT therapy lamps. MORE on why the low-intensity Lo-LIGHT is as effective as bright light therapy

The patented Lo-LIGHT technology comfortably shifts the internal body clock as effectively as bright white light. Lo-LIGHT lamps screen out the hazardous wavelengths of blue visible light. The Lo-LIGHT can therefore be used by people whose conditions make them sensitive to eye damage. This includes people with pre-existing ocular conditions, those with diabetes or other diseases that predispose them to retinal damage, and those taking photosensitizing medications, or herbal supplements like St Johns Wort.

PART II: Seasonal Changes, The Body Clock, and Depression (SAD)

NOTE: Studies at university and military research centers show low-intensity GreenLIGHT technology is also useful for helping people adapt to working the night shift.
See GreenLIGHT Fatigue Counter-Measures for Night Shift Workers.