Light Therapy and Circadian Health for Depression and Other Illnesses

A drug-free, clinically proven approach to wellness and freedom from depression and other illnesses.

Mal-illumination, the Modern Civilization Disease

Earth's animals and planets evolved over millions of years in the presence of the sun’s light, and without this precious light, life as we know it would disappear completely.

Since the dawn of human history, people have lived and worked outdoors during the light of day, being active and vibrant, absorbing light energy from the sun. An average of 10 hours each day, 70 hours weekly, was common. With the advent of Edison’s long-lasting lightbulb, over the last 100 years people have moved indoors, away from the natural light, the light that so faithfully regulated our circadian rhythms and energized our brain cells and bodies.

Today, we spend an average of less than 30 minutes a day, or a mere 3½ hours per week in daylight (often much less than this), according to a study done by Daniel Kripke, MD, Professor of Psychiatry at the Univesity of California at San Diego.

Do you think this meets our bodies’ minimum daylight requirements? Not by a long shot!

Scientific research has proven that our circadian day-night rhythms (see below) are dependent upon light entering our eyes to regulate our bodies’ master clock. Just recently it has been discovered that a certain part of the retina is specifically designed by nature/God to detect light levels. According to the quality and quantity of light received, key hormones like serotonin and melatonin are released in the brain to set our daily rhythms.

Today, most people suffer greatly from mal-illumination-- daylight deprivation and too much artificial light at night. Is it any wonder we experience many of the symptoms of being out of rhythm?

Depression, hormonal imbalances, sleep disorders, fatigue, headaches, weight gain, PMS, lowered immune responses, vitamin D/calcium deficiencies, and lack of vitality are but a few of the many health problems associated with the lack of full-spectrum, natural light.

Worse yet, most of us spend our days at the workplace being bombarded with “light pollution” from inferior indoor lights (flickering fluorescents and computer monitors) that spew painfully inadequate and distorted light frequencies instead of beneficial, full-spectrum daylight.

Circadian Rhythms, the Rhythms of Nature

Much of nature is composed of rhythms or cycles. Common rhythms include the four seasons and earth’s 24-hour rotation. Our bodies also have rhythms, mostly tied to natural rhythms. Nature, through its 24-hour cycle of day and night, has provided us with a template or pattern that anticipates what we need to be healthy. When properly synchronized, our bodies will respond to nature’s cues.

Have you ever wondered why your body needs sleep? Or what causes it to wake up? Or why it gets hungry? These patterns are all part of how your body responds to its cycle, its Circadian Rhythm. Circadian Rhythms are our body’s natural cycles that control appetite, energy, mood, sleep, and libido. Circadian Rhythms control the timing, quantity and quality of hormones and neurotransmitters the body produces and eventually secretes. Hormones and neurotransmitters are the elements determining how we feel, our sleep patterns, our appetite, our sex drive and other sleep- and mood-related issues.

What is Circadian Balance?

As in nature, life follows rhythms and cycles. These cycles are well-defined rhythms and nature’s way of maintaining balance. When functioning properly, our Circadian Rhythms create Circadian Balance. This balance happens when we are in harmony with nature’s cues. We can get up early, feel great during the day, and then sleep well at night. We are feeling our best—because we are in our natural rhythm!

Nature’s most important cues come from the sun. But because of work schedules or changes in seasons, we usually don’t get all the natural light we need, and so we fall out of sync with nature.

Our bodies respond to nature’s cues to create their ideal rhythms. When functioning properly, the human Circadian Rhythm will respond to the morning light of a new day. This light will cue the body to produce serotonin, cortisol, and other hormones and neurotransmitters that fully awaken a person and cause the normal rise of blood pressure and body temperature.

At sunset, the body receives another of nature’s cues. As the sun goes down and light is reduced, the body secretes the hormone melatonin. Blood pressure then drops as the body prepares for sleep and eventually falls into slumber.

What is a Circadian Rhythm Disorder (CRD)?

When we are out of balance, the quantity, quality and timing of hormone and neurotransmitter secretion are impaired and our bodies suffer a Circadian Rhythm Disorder, or CRD.

A CRD means your body is producing hormones, chemicals and neurotransmitters in the wrong amounts and/or at the wrong time of the day. Circadian Rhythms stimulate the timing and production of countless hormones and chemicals that affect your sleep and mood. Circadian Rhythms permeate practically every aspect of our lives because they so heavily influence the chemicals that determine our mood and sleep.

Given nature’s day-night cycle and its tremendous effect on our psychological, behavioral, physiological, and hormonal rhythms, the implication is clear: orderly rhythm is essential for optimal health. The obverse is also terribly true: rhythmic disorder is a recipe for potential disaster to our health and wellness. Numerous scientific clinical studies have proven this.

Clearly, many mood disorders (like depression) and sleep problems (insomnia and also excess sleeping) can be traced to a Circadian Rhythm disturbance.

Because the Circadian Rhythm influences so much of how a person feels or sleeps, if we desire optimal health, we need to properly care for our Circadian Rhythm. If it is out of balance, various aspects of our health will be impacted and we will be out of balance. Fortunately, after decades of research, science has found the way to create Circadian Balance.

Light Therapy Resets/Stabilizes the Circadian Clock

Light is the most effective way to synchronize the body-mind with the 24-hour day-night cycle. In the early 1980s two groundbreaking studies were made. One was conducted at the Albert Einstein College of Medicine in New York, the other, at the National Institute of Mental Health. Both studies concluded: specific wavelengths, intensities and color-spectrum of light (not available in ordinary room lighting) could reset the circadian clock and create Circadian Balance. Since that time, many studies have been conducted to understand how and why light therapy works.

Lighten up! Come into Rhythm Naturally.

Since the dawn of history, humans have lived and worked outside in the light of day, active and vibrant, absorbing light from the sun. Sadly, we have unwittingly become contemporary cave-dwellers who no longer get enough daylight to receive the cues that nature intended. The tragic result is that millions of people suffer from some form of CRD.


The eminent, much-awarded photobiologist Dr. John Ott (1909-2000), author of Health and Light and numerous other publications, for over 40 years pioneered research with full-spectrum, natural light on living organisms—plants, animals and humans. Ken Ceder, founder-president of the BioLight Group, and his colleagues, followed the precise recommendations of Dr. Ott to produce the Intelli Lite as an appropriate full-spectrum task-light for work and home. This revolutionary light therapy system utilizes all three of Dr. Ott’s original patents for the world’s only safe, radiation-shielded, full-spectrum light therapy system with added ultra-violet light (UV) for all-important Vitamin D metabolism. The Intelli Lite’s patented ergonomic design outputs health-enhancing light that actually mimics natural daylight, without the harmful effects of getting too much sunlight. The Intelli Lite can provide the wellness benefits of sunlight (including safe UV) while one works (especially at one's computer), reads, plays, or watches TV. The BioLight Group, along with other companies, also sells “bright light therapeutic devices,” a.k.a. “bright light boxes,” for more intense, shorter periods (15 to 30 minutes) of full-spectrum light therapy.


More Wisdom on Circadian Health: Lights Low and Lights Out for Better Sleep and Regulation of Hormones and Neurotransmitters like Melatonin for Depression, Obesity, etc.

Researchers T.S. Wiley and Bent Formby, in their acclaimed book Lights Out: Sleep, Sugar, and Survival (NY: Simon & Schuster, 2000), reflecting on epidemic diseases in our midst like depression, obesity, heart disease, diabetes, and cancer, examined more than a decade of research (by year 2000) at the National Institutes of Health. Wiley and Formby found that many of these disorders can be helped with a solution as simple as turning off a light bulb and paying more attention to nature’s cycles of day-light and night-darkness.

Before the invention of the longlasting light bulb and the electric power grid, when the sun set each dusk, the environment grew dark. If people stayed up late, their activity was lit by the dim red glow of fire or candles. When night fell, most people went to bed and slept. In the winter, people spent up to 14 hours a day in the dark.

There's definitely a bio-chemical process involved here. Cryptochromes in the blood pick up the blue spectrum of sunlight and carry it throughout the body. In the summer the body gets the message to produce hormones that say, “Eat all you can and build up a fat pad so you will survive the dark winter famine.” Today artificial lights trick the body into thinking every day, year-round, is the “summer season” to eat a lot and gain weight. Long hours of light cause insulin release to store extra carbohydrates as fat and cholesterol, in order to have something to live on when summer is over.

Staying up late under artificially bright lighting means that insulin stays at higher levels in our bodies during the night when it should be falling to lower levels. The hormone cortisol falls so late that it will not come up normally in the morning. Prolactin does not come up until 3.5 hours of melatonin have occurred, so after a night with too much light the prolactin persists at too high levels in the morning. If cortisol is not high enough to enhance dopamine, a person may feel rushed and have poor memory and trouble planning. In the afternoon and night, the appetite comes on voraciously.

Melatonin would have suppressed appetite at night, but does not form with the artificial lights on. After sunset the light bulbs, computer monitor, and TV screen tell the body to eat carbohydrates and gain weight. Attempting to burn off the extra weight through exercise means cortisol level goes up. The insulin response system maximizes to mobilize blood sugar and may eventually lead to insulin-resistance.

The length of hours of light and hours of dark each day regulates hormones like insulin, serotonin, dopamine and melatonin. Light shuts off melatonin production at the preoptic site connecting to the pineal gland. Research on rats showed that even the light of less than a candle in the dark phase (night) disrupts the production of the antioxidant melatonin and increases tumor growth. Whereas long dark nights change the heart’s metabolism from sugar burning to fat burning.

Artificially long hours of light—every day, all year long—eliminate seasons as far as the body can tell. Some people get depressed in the winter. They may also go for months with no exposure to natural sunlight. They are exposed to murky artificial light 24 hours a day.

This unhealthy syndrome can be usefully countered by 1) reducing the amount of artificial light in your environment at night and replacing it with soft full-spectrum lighting, and 2) by getting adequate sunlight or full spectrum indoor light during the day.