The quality of the light has a direct impact on the quality of sleep and rest . Choose bulbs with appropriate intensity and color temperature and you will sleep peacefully. Many people find it difficult to start in the morning and find it difficult to focus on work or school without a cup of coffee or tea. The problem may be in the light, or in insufficient lighting at home or in the workplace. Interesting investigations have been conducted to confirm this. A study found that students who study with lighting that reproduce natural lighting on a cloud-free day focus better and have better results.
Man evolved under the scorching rays of the sun, and life on Earth depends on him. Natural light is a vital dynamic and source of health: it gives us rest, energy, vitality and good humor, strengthens the basic immune system, provides vitamin D for calcium absorption and cancer prevention – it acts on the nervous system and regulates the cycle of activity and rest, day and night.
This is why it is important to have suitable artificial lighting that is as similar as possible to the beneficial sunlight, which changes throughout the day.
The color frequencies of the light source can be cold (bluish and greenish) or warm (yellowish and reddish) depending on its temperature, which is measured in degrees Kelvin.
On a very sunny day, the light temperature can be over 5,800 degrees Celsius. On the other hand, the time of sunrise or sunset ranges between 2000 and 2200 degrees Kelvin.
Thus, white and blue LEDs (above 4000 ° C) are best suited for work in the morning, as they energize you, but it is not recommended to expose them in the afternoon or at night, as they may cause excitement and sleep problems.
In the afternoon, the bulbs should emit warm white (below 3500 ° K) and at night, yellow-orange (below 2000 ° C). The problem is that we usually expose ourselves at night to light from all kinds of electronic devices (computers, tablets …), which contain bluish LEDs that interfere with the production of melatonin, the hormone that stimulates sleep.
We should avoid this type of light and prefer something similar to the warmth of a candle.
In the technical specifications of the lamps we can read the abbreviation IRC (or CRI, in English): it is “color rendering index”, that is, the ability of the lamp to reproduce the true colors of objects.
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If the ratio is low, as is the case with fluorescent, then the color differs from the true color. That is why in some clothing stores it is sometimes difficult for us to distinguish between color and to confuse black and dark blue, for example.
A lamp with a CRI greater than 90 or 95% (“full spectrum”) reproduces the maximum solar spectrum and will be most suitable in situations where we need to estimate colors well. Generally speaking, the best CRI lamps have a color temperature above 5000 ° C.
Density is the luminous flux that falls on a certain surface and is measured in lux. In the midst of nature, a maximum of 120,000 lux can be enjoyed on a clear day at noon; 15,000 on a cloudy day, 500 at twilight, and 0.25 on a full moon night. Depending on the activity you are doing in an indoor space, you will need a different intensity, because the visual effort that is made when reading is not the same as that required to walk down the aisle, for example.
When choosing a lamp, in the technical data, the intensity is reflected in lumens. Thus, a 1000 lumen bulb would achieve an intensity of 1000 lux if it were to illuminate only 1 meter. Using this data, you can get an idea of how many light sources and how much intensity you need to illuminate a given space. In general, light approaching 1,000 lux in work areas is suitable for feeling awake. In the kitchen 300 is enough, and in the corridor 50.
At home, in the morning, the ideal situation is to open the curtains to allow the sunlight to enter and activate the hormones that keep the body awake (cortisol, adrenaline, and dopamine), at the same time that melatonin, the sleep hormone, is slowed down.