Thinking through the lighting in the house, in most cases we consider only its functionality and compliance with the overall style of the interior. Wall and ceiling lamps, as well as table lamps in our understanding should be in harmony with the color of the walls, ceiling, curtains and other elements around us. But many do not even suspect that the use of a banal nightlight may have any impact on our health. How does the lighting of a different color affect our body at night and whether we need a nightlight in principle.
Light, hormone melatonin and circadian rhythms
Electricity, of course, brings great benefits to humanity, facilitates the solution of many problems and makes possible what we could not even think about before. But artificial lighting is still foreign to our body. Our ancestors, living without electricity, worked in the daytime, and slept in complete darkness. Artificial light has radically changed the life of modern man. We can work at night, in the evening, sit in lit rooms, and sleep a little longer during the day.
Light is perceived by the retinal ganglion cells, which use it to adjust the biological clock. Photosensitive pigments of eye sticks (rhodopsin) and cones (iodopsin) help the brain to obtain information about the color, shape and movement of objects in the real world. There are also special ganglion cell containing another photosensitive pigment – melanopsin. Its main function is to regulate circadian rhythm, that is, to control certain biological processes depending on the time of day.
Obtaining information about the onset of darkness, the pineal gland of the brain (epiphysis) begins to actively produce melatonin, a sleep hormone. Its maximum concentration is observed from midnight to five in the morning. During the night, in the absence of any disturbances, about 70% of melatonin is produced, and during the day, under the influence of sunlight, its synthesis is markedly slowed down. Light suppresses the production of a hormone that is involved in the activation of the immune system, slowing down the aging process and many other vital functions of our body.
Some studies have shown that melatonin reduces the intensity of the development of cancer tumors. So, women who are accustomed to sleep in the light are more susceptible to breast cancer. No less dangerous to the health of the night shift work. According to statistics, people who have worked at night for 30 years are 2.2 times more likely to experience cancer. At the same time, men who have only three night shifts a month already fall into the risk group for the development of prostate cancer. Also, night lighting increases the likelihood of tumors in the rectum and colon. In addition, the risk of obesity, the development of metabolic syndrome, coronary heart disease and gastrointestinal ulcer increases.
Employees of Harvard University have found that sleep in the light also threatens with an increase in blood sugar levels and a decrease in the production of leptin, a satiety hormone. Therefore, if a person likes to sleep in the light, he risks “earn” diabetes and obesity.
Effect of light on mood
Experts say that not only the regulation of biological rhythms depends on light. Lighting also affects the cognitive functions of the brain, mood, and emotions. And the value is not only the brightness of the light, but also the color of the lighting. Specialists from the University of Haifa observed people who needed to make an important decision in the face of uncertainty. Volunteers made bets on the lottery simulator, reading information from the monitor on a green and red background. The results of the study showed that when making bets on a red background, people more often thought about losing, and on green – about winning.
In addition to the color of illumination, its intensity also influences emotions. In bright light, volunteers during the study were much more willing to donate their own money to charity, showing greater altruism.
Speaking about the influence of light on the mood, it is worth mentioning another experiment conducted on the hamsters. In the course of the study, female rodents spent nights in the dark for one week, then spent another week at night in the dim light of blue, white, and red. The hamsters’ mood was checked with the help of a sweet syrup, which they practically did not drink when depressed. The results of the study showed that hamsters drank the most syrup after nights spent in darkness or under red lighting. Such conclusions can help minimize harm to people who are forced to work at night.
Another study by staff at Oxford University helped determine which lighting color helps you fall asleep faster. Blue, violet and green colors were chosen for work. The study was performed on mice. It turned out that with green light the rodents fell asleep for 1-3 minutes, with purple for 5-10 minutes, and with blue for 16-19. But the results of such research are ambiguous, because for mice, unlike people, night is the time of wakefulness.
There are separate studies on the effect on the body of blue. It turned out that the effect of blue light on the photoreceptor cells of the retina causes the accumulation of retinal (a form of vitamin A), which becomes toxic in excess. Also, blue light triggers processes that increase the concentration of calcium in the cytoplasm. With constant exposure to blue light, macular degeneration develops, resulting in a loss of visual acuity, as in natural aging processes. A similar experiment was conducted with other colors (yellow, green and red). They were safe for the eyes.
Conclusions: Do I need a nightlight and how to protect my health?
Of course, in many cases it is impossible to do without a nightlight. But it is best to abandon the instruments, working all night and illuminating the room with dim lights. The night light should be placed next to the bed so that it is always possible to turn it on in the dark for a short time without any problems. It is best to give preference to the red color of lighting, which has the least impact on the production of melatonin and, accordingly, the safest for health.
Also important is the type of lamp used. It is best to buy lamps with modern LED light bulbs.
Picture Credit: ErikaWittlieb