How light affects a person’s health

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1. Overview

Artificial lights in your home or office can influence the way you feel and can even affect your health.

In fact, exposure to certain types of artificial light before bedtime and at night may increase risk of type 2 diabetes, hypertension and cancer.


1. Overview
2. Why is light so important?
3. How much light is necessary for a person?
4. Additional sources of artificial light in winter
5. How often should the additional sources of light be used?
6. Light boxes can be used safely
7. Are there any side effects of the use of light boxes?

2. Why is light so important?

Our bodies need a certain amount of medium-intensity light, in some moments of the day to act as benchmarks for the body’s internal clock.

Light helps us wake up in the morning, provide energy and alertness, while evening light indicates that the time is advanced and it is time to sleep. Light is essential for the health and welfare of any person.

Adequate amount of light in certain parts of the day affects the level of alertness, mood, productivity, sleep, and many aspects of a person’s physiology.

3. How much light is necessary for a person?

The amount of light that a person needs depends on the time of day and the activities they carry out. During the day you need a high level of light to maintain alertness and vigilance necessary to conduct daily tasks, while evening and night light will be reduced for the body to relax and prepare for rest.

To ensure that the body receives enough light during the day it is important to spend an hour or more outdoors. A walk during your lunch break, even under the summer sun will be beneficial to health, because natural light is always better than artificial, being stronger and lighter.

In fact, sunlight measured between 50,000 to 100,000 lux (unit of measurement for light) compared with normal light (250-500 lux) or even a light box that can reach 1000 lux.

Using artificial light at night, approximately between 9 pm and 8 am (depending on regular sleep pattern), decreases the levels of melatonin, a hormone produced by the pineal gland in the brain.

The hormone is vital for healthy body because it controls hearth rhythm or biological clock. If the amount of melatonin is low, physiological and mental functions are affected. This has an impact on:
- Ability of a person to sleep well;
- A person’s ability to think clearly;
- Biological clock and hormone production;
- Regulation of blood pressure and glucose levels.

Poor sleep quality that persists over time increases the risk of developing various diseases and conditions such as diabetes and depression.

4. Additional sources of artificial light in winter

It is quite difficult for anyone to enjoy outdoor natural light in winter, especially if working late, for example.

An alternative therapy could be additional sources of artificial light. Phototherapy can have positive effects on the body. There are several types of light boxes and artificial sources of light that can be used when drowsiness occurs. They are designed to apply biological responses that make a person more energetic and alert.

These can also be useful for seasonal depression or lethargy. When using a light box or other artificial light source, it is important to use it especially in the morning, to get maximum effect and not late at night, when they can disrupt sleep and the body’s biological clock.

5. How often should the additional sources of light be used?

Phototherapy effects vary from one individual to another and depend on the reason for which they are used. Phototherapy may be necessary in any of the following situations:
- To compensate for the lack of light in a dark office;
- As an incentive if lethargy or fatigue occurs;
- As an alternative for the treatment of seasonal depression, in the dark days of winter.

6. Light boxes can be used safely

When purchased from an accredited manufacturer, light boxes are safe and can be used safely. However, should not buy products that are not certified as medical devices, otherwise there is no real guarantee that a box was especially designed for therapeutic purposes.

Sometimes bright light can be harmful to eye health; products intended for phototherapy will include special screens and filters that will minimize the amount of UV rays.

7. Are there any side effects of the use of light boxes?

Rarely, some people may experience side effects such as headache, nausea and hyperactivity. These disadvantages can be ameliorated by turning the light off and the duration of time finding provides beneficial organism.

Nighttime use of phototherapy is dangerous for health. Normal functioning of the human body requires regular alternation of day and night, light and darkness. In the dark, the pineal gland synthesizes melatonin, but the influence of light in night hours suppresses this synthesis.

Melatonin is a biological blocker of malignant tumors. The more intense light at night, the stronger is suppressed melatonin synthesis. Some people are more sensitive to light at night than others, and women are more susceptible than men.

Light pollution can cause premature aging of the reproductive system and can increase the risk of breast cancer and large bowel in women. Those who work at night often suffer from colorectal cancer. In addition irregular light can cause sleep disturbances, gastrointestinal and cardiovascular diseases, metabolic disorders and diabetes.

These conclusions were confirmed by the results of experiments with rodents that constantly react to light in the same way as humans. Cancer cells often have multiplied in mice which were exposed permanently to bright light; they are more susceptible to chemical carcinogens and malignant cell inoculation.



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