The following is reprinted from Apollo Health

As with most medical discoveries, the science of light therapy is advancing rapidly. Technology is changing and our understanding of how and when to apply light is much better than it was even ten years ago. Products are becoming smaller and more portable, and yet are becoming more effective at delivering the specific type of light that will yield a quicker, stronger response. The following information explains the most important developments, and how they can help light therapy users respond more effectively than with conventional light therapy treatment:

Groundbreaking discovery

In 1984, Dr. Norman Rosenthal at the National Institute of Health published the groundbreaking report on Winter Blues and light therapy. Since that time, researchers have tried to determine what type of light, the time of day and how much light yielded the most effective response. This is known as the dose response relationship, or in layman's terms, the light therapy equation, and answering these questions will help light therapy users respond more effectively than with conventional equipment.

15 minutes vs. 2-3 hours

As researchers have learned more about the dose response relationship, they have been able to significantly improve response while reducing the amount of time one needs to be exposed to light. For example, one can now receive better results from 15 minutes of light than sessions that took two to three hours a decade ago.

Circadian rhythms & the timing of light

Fellow researchers at the NIH, Dr's. Alfred Lewy and Robert Sack, discovered that Winter Blues was associated with 'out of whack' circadian rhythms. Circadian rhythms are the daily signals the body clock produces that tell us when to wake up, be energetic and go to sleep. These rhythms also control the daily mood and energy hormones. Dr's. Lewy and Sack found that Winter Blues patients had body clocks that were not in sync with a 24 hour clock, and that using light at specific times of the day could re-entrain their circadian rhythms to a normal pattern. Once their body clocks were corrected, they would produce the right hormones at the right time of day, relieving the symptoms of Winter Blues. Dr. Lewy also helped elucidate the phase response curve, explaining how different intensities of light during the night cause varying reactions. Their 'Phase Shift Hypothesis' is the currently accepted explanation of how light works with circadian rhythm problems such as Winter Blues.

Light intensity

In the early studies on light therapy, researchers noted that a light level of 2,500 lux was needed to produce a therapeutic response. The problem was that this therapy was too inconvenient, as it required two to three hours/day. Dr. Michael Terman and colleges at Columbia Presbyterian Medical University in New York began experimenting with increasing light intensities. They found that as the intensity increased, so did the response, and patients needed less time to respond. 10,000 lux seemed to yield the greatest response with the shortest treatment time of only 30 minutes. Intensities beyond 10,000 lux yielded no greater response.

Type of light

In the early years of light therapy, Dr. Lam and colleges at the University of British Columbia, conducted studies on what type of light was most important. One small study comparing broad spectrum UV light to broad spectrum, non-UV light showed a slight advantage with UV light. However, larger follow-up studies showed no increased advantage with UV light, and because of the risk of eye damage, UV light was discouraged. Unfortunately, some small companies used these first results and still advocate using UV light for Winter Blues related conditions.

Full spectrum vs. broad spectrum or white light

Dr. Lam's studies with full-spectrum light vs. broad spectrum or white light showed that both light sources worked with equal efficacy. Although some small studies originally touted the benefits of full spectrum light on general health, no study has found full spectrum light to be superior to white light in relieving Winter Blues or circadian rhythm problems. Although many smaller companies will push full spectrum, CRI and Kelvin color temperature, these claims are exaggerated, and none of these companies have participated in any published light therapy research. Further, these measurements are not accepted by the SLTBR or medical review journals.

Effective bandwidths

Dr. George Brainard and colleges at Thomas Jefferson Medical University in Philadelphia are perhaps the foremost experts on the effects of different types of light. For over a decade, Dr. Brainard has been working to understand how specific bandwidths of light affect the body. Researchers at TJU constructed spheres that could illuminate a monochromatic wavelength of light. Participants placed their heads in these spheres during the middle of the night, when their body clocks were most receptive to light.

Discovery of the decade

What Dr. Brainard and his colleges discovered is perhaps the most significant advancement in light therapy in the last decade. Light in the range of 447-484 nm (nanometers) is responsible for suppressing melatonin and shifting circadian rhythms. Indeed, this specific bandwidth of light is up to ten times more effective than other wavelengths. By using this specific light or boosting it in conventional light therapy, researchers hope to be even more effective in eliciting a more effective and quicker response. In one recent research report, Dr. Brainard's colleges concluded that light therapy via a 470 nm LED array appears to be an effective treatment for subjects with Winter Blues.

Would you like to balance your circadian rhythms? We carry the best that Apollo Health has to offer in Light Therapy.