Sunlight helps you to fight colds, tiredness and depression. Lack of sunlight causes an increase in the production of melatonin (the hormone which makes us feel sleepy) and a decrease in serotonin (the hormone which makes us feel happy).
The form of light therapy most commonly used today is known as bright-light therapy. It requires that you sit near a special light box fitted with high-intensity light bulbs, which may provide either full-spectrum or white light. This type of light therapy has been proven to be particularly useful in treating seasonal affective disorder (SAD), also known as the "winter blues," a form of depression that occurs as the amount of daylight wanes with the change of seasons. It has also been shown to be effective for some sleep disorders. The amount of exposure you need depends on the intensity of light you use and could range anywhere from 15 minutes to 2 hours. The intensity of light usually ranges between 2,500 and 10,000 lux (10,000 lux is about 20 times as bright as normal indoor lighting).
How does light therapy work?
Exposure to bright light effects changes in a person's circadian rhythms. Thousands of people find relief through bright light therapy, although the physiological mechanism is still uncertain. Such exposures suppress the secretion of melatonin (which makes us sleepy), and increase the secretion of seratonin (which keeps us alert and full of energy), but which of these influences are the primary mechanism is not yet known.
The best way to get light therapy is to go outside for about 30 minutes and raise your face to the sky (don't look directly into the sun, however). Even on a cloudy day, the sun provides the full spectrum of light that the body needs.
When should light therapy be used?
Recent studies show that light therapy may be most effective when used first thing in the morning upon awakening. You and your health professional can determine when light therapy works best for you. While response to this therapy usually occurs within 2 to 4 days, it may take up to 3 weeks of light therapy before symptoms of SAD (such as depression) are relieved.
Other Benefits of Light Therapy
Light therapy has also been used to treat the depression associated with PMS, chronic anxiety and panic attacks, severe jet lag, and eating disorders such as anorexia nervosa and bulimia.
Some people have been able to avoid, or at least minimize the effect of, jet lag with light therapy. Experts recommend that if you are planning a trip eastward-to Europe, for example-you may want to try to get up a few hours earlier than normal on the day you intend to fly. Take a walk and soak up the sun, or stay inside with all the lights on. Stay awake and surround yourself with light. Then, once you arrive at your destination, try to stay outside in the sun for an hour or two. By doing so, you may be able to move your clock forward to more closely match the rhythm of life in the new time zone.
Early Morning Insomnia
Those suffering from this illness, find that they cannot sleep in the early morning. In a 1993 study conducted at South Australia, 9 persons who have suffered from early morning insomnia underwent bright-light stimulation in the evening. They were given photo therapy that involved exposure to 2,500 lux light from 10 p.m. to midnight. The result: They fell asleep at their normal times; but, stayed asleep an average of one and a half hours longer than usual.
Types of light therapy are:
Coloured Light Therapy
It is type of light therapy utilizes filtered floodlights or small beams of light to bathe the skin in different shades of color (usually red, but also white, blue, violet, and occasionally other colors), sometimes in flashing patterns.
A large study in schools in Alberta, Canada, conducted over a whole school year, compared pupils in classrooms with conventional fluorescent lights and dull coloured walls against pupils in classrooms with full-spectrum lighting and walls painted with with warm colours. Both changes separately showed significant improvements in academic performance and discipline and decreases in absenteeism due to illness, and the combination of changes was even more effective.
There is also an entire school of optometrists who use coloured light to treat patients. The light is shone into the patients' eyes from a special light source equipped with a variety of coloured filters. The underlying principle of this therapy is to balance the activities of the sympathetic and parasympathetic nervous systems using colours that are either stimulating or calming. Practitioners can be found in many countries, though the treatment is most widespread in the US.
Pulsed Light Therapy
If bright light and coloured light can have such an effect on the brain, mind and body, it is to be expected that pulsed light would have even more effect. Pulsed light certainly grabs one's attention; neurologically speaking, neurons tend to report only changing stimuli, quickly tiring of anything steady. So pulsed light might be considered to be a more aggressive form of light therapy, for more severe conditions.
Pulsed light is shone into the eyes either from a mask or goggles worn by the patient or by having the patient sit in front of a larger pulsed light source one or two feet away. Typically the treatment is applied for 15 or 20 minutes per day.
The major difference between home made and purchased light boxes is that the ones bought from reputable manufacturers have an ultraviolet filter built in. Without such a filter, use of the light box increases the possibility of skin cancer and cataracts.
Who Should Avoid Light Therapy?
- Light therapy is not advisable if your skin or eyes are highly sensitive to light.
- A wide variety of drugs can increase your sensitivity to light.
- Check with a health-care professional before starting any form of light therapy.
- Never look directly into the light source during your therapy.