Sunlight - Wikipedia, the free encyclopedia
Life on Earth
The existence of nearly all life on Earth is fueled by light from the sun. ---
Heterotrophs, such as animals, use light from the sun indirectly by consuming the products of autotrophs, either directly or by consuming other heterotrophs. The sugars and other molecular components produced by the autotrophs are then broken down, releasing stored solar energy, and giving the heterotroph the energy required for survival. This process is known as respiration.
Effects on health
A lack of sunlight, on the other hand, is considered one of the primary causes of seasonal affective disorder (SAD), a serious form of the "winter blues". SAD occurrence is more prevalent in locations further from the tropics, and most of the treatments (other than prescription drugs) involve replicating sunlight via sunlamps tuned to specific wavelengths of light or full-spectrum bulbs.
Full-spectrum light - Wikipedia, the free encyclopedia
"Full-spectrum" is not a technical term when applied to an electrical light bulb but rather a marketing term implying that the product emulates natural light.
Products marketed as "full-spectrum" may produce light throughout the entire spectrum, but actually do not produce an even spectral distribution, and may not even differ substantially from lights not marketed as "full-spectrum".
Measurement
Color temperature and Color Rendering Index (CRI) are the standards for measuring light. In general, Kelvin temperature ratings of 5000 K or higher and CRI of 90 or higher denote a truer, full-spectrum light.
Use in seasonal affective disorder
In recent years, full-spectrum lighting has been used in the treatment of seasonal affective disorder (SAD) through the use of "light boxes" that mimic natural sunlight, which may not be available in some areas during the winter months. Light is an environmental stimulus for regulating circadian cycles.
Lightbox therapy, otherwise known as phototherapy, is a recognized modality for depression (such as SAD). Depending on the quality of the light, it is estimated that 10,000 lux is needed for effective treatment. Not all light boxes are the same. It is possible the phosphors used to mimic the natural light emit harmful ultraviolet radiation.
Artificial sunlight - Wikipedia, the free encyclopedia
Light therapy
Artificial sunlight is found useful in treating and preventing Seasonal affective disorder (also known as winter depression, which brings about depressive symptoms specifically in winter), and Delayed sleep phase syndrome, in which the circadian (day V/s night)-rhythm is disturbed, and the individual tends to fall asleep at the same time much after midnight.
Artificial sunlight may also be useful in prevention, or minimizing the severity of jet lag. Although, UV light is used in treatment of psoriasis and eczema (as PUVA therapy), and in treatment of acne, (in which case it is also accompanied by application of red light), it is not the entire spectrum of visible light that is employed.
There's also the fact that people have noticed more active birds when using full spectrum lighting... so I do believe that natural or artificial sunlight is beneficial to birds in some way!