The sun is our only source of light on Earth. On the condition of not exposing oneself directly or for a long time to its rays, it is a source of benefits which one must know how to take advantage of.
1 Fortify bones
Under the UVB effect, some cells of the skin react, synthesizing vitamin D (cholecalciferol, ergocalciferol), essential for fixing both calcium and phosphorus. It prevents rickets, as well as osteoporosis in the elderly, and promotes the growth of children. On average, during the year, 15 to 30 minutes of daily exposure suffice.
UV RAYS. Ultraviolet (UV) radiation from the sun breaks down into three rays: UVA, UVB and UVC differ in their wavelengths and their ability to cross certain media. The energy of the radiation is all the stronger as the length is short, their penetration through the skin is therefore deep when the wavelength is high.
2 Regulate the internal clock
The most powerful synchronizer of the biological rhythm is the light, our eyes transmitting this signal to the brain which controls the secretion of specific hormones. The functioning of the body (sleep / wake, temperature, hormones, memory ...) is thus subjected to a biological rhythm set on a cycle of a day of more or less 24 hours. The internal clock - located in the suprachiasmatic nuclei of the brain - is thus permanently resynchronized on this precise cycle.
3 Synchronize your sleep
The light perceived by the retina is transmitted directly to the suprachiasmatic nuclei of the brain that relay information to a small gland, the epiphysis. At the end of the day, it secretes melatonin, a hormone that makes it easier to fall asleep. The external brightness can stimulate or diminish its production. Exposure to light in the evening, delays the production of melatonin, and therefore falling asleep. A bright exposure in the morning will, on the contrary, advance the clock.
4 Improve morale
In 1984, the American psychiatrist Norman Rosenthal demonstrated the link between light and depression. Since then, work has postulated that this stimulating action on the morale acted through the serotonin, a neurotransmitter involved in the regulation of mood, sleep and appetite. The use of light therapy for seasonal depression was validated in 2005.
5 Decrease hyperactivity
Lack of light intensity may explain one-third of children with ADHD and up to 57% of adults with ADHD, according to researchers at Brainclinics -Low). Indeed, prevalence maps of ADHD and those of solar intensity measured in ten countries are consistent. People enjoying a high intensity of light would be "protected", thanks to better sleep patterns.
6 Better learning
Light is a powerful stimulant for awakening and cognition. Its impact on the brain regions needed to perform a cognitive task depends on the specific color of light received over an hour ago. According to the University of Liège and Inserm. A prior exposure to an orange light helps to better perform a task than a blue light, that of computers in particular. And this by the photopigment (melanopsin) of the suprachiasmatic nuclei that receives the light reacts differently according to the color of it.
7 Treat skin diseases
Yes, the light heals (phototherapy). Everything happens not on the beach ... but in the hospital, in cabins specially developed. Two types of radiation (UVA, UVB) are used against the sporiasis, the eczema ... But beware, if the UV rays seem beneficial to the lesions of acne which regress at first, they explode in the autumn because an inflammatory flare secondary to sun exposure.