Many people in life like to turn on the night light and accompany themselves to sleep all night; There are also people who like to turn off all the lights and sleep in a dark bedroom.
However, studies have found that long-term exposure to bright light may have adverse effects on physical health.
The brighter the lights at night
The higher the risk of diabetes
In July 2024, a study published in The Lancet found that the brighter the light at night, the higher the risk of developing type 2 diabetes, after studying 84,790 participants!
After adjusting for the model, all the data showed that the brighter the light at night (00:30-06:00), the higher the risk of developing type 2 diabetes. Conversely, brighter light during the day (07:30-20:30) is associated with a lower risk of developing type 2 diabetes.
It can be seen that the length of nighttime light directly leads to an increased risk of type 2 diabetes, and there is no significant gender-specific difference in the relationship between light and diabetes. Avoiding nighttime light may be an effective strategy to reduce the risk of type 2 diabetes.
The study covered a wide range of people, including people who work night shifts, people who like to play with their mobile phones at night before falling asleep, and people who are afraid of the dark and need to turn on the lights to fall asleep, all of which may lead to an increased risk of type 2 diabetes.
To maintain good health, we still need to minimize unnecessary nighttime light exposure as much as possible, such as going to bed early and turning off the lights while sleeping.
The light is too bright at night
And these disadvantages!
1. Increased risk of thyroid cancer
In 2021, the authoritative medical journal "Cancer" published a study on night lights, a large cohort study of 464371 participants, and the results showed that too strong artificial lighting at night can increase the risk of thyroid cancer by 55%, and the risk is higher in women.
Studies have shown that those with the highest levels of exposure have a 55% increased risk of thyroid cancer, with papillary thyroid carcinoma being the main type of thyroid cancer, compared to those who were exposed to the lowest nighttime lights. In terms of gender, nighttime lighting affects women more than men, increasing the risk of cancer by 81% in women and 29% in men.
The reason for this, according to the researchers, is that the exposure to nighttime light disrupts the body's biological clock, thereby increasing the risk of thyroid cancer.
2. Increase the risk of breast cancer and prostate cancer
In fact, there has been research for a long time on the idea that light at night increases the risk of cancer. In 2018, researchers in Spain published a cancer study showing that artificial lighting at night can increase the risk of cancer.
The results showed that there was little correlation between nocturnal exposure in the visible light spectrum and the risk of breast cancer. However, the impact of blue light spectrum light on breast cancer is very obvious, and exposure to the blue light spectrum (mainly in cities with LED lighting) increases the risk of breast cancer by 1.47 times.
In the blue light spectrum, the risk of prostate cancer increases with the increase of exposure, and the risk of developing prostate cancer increases by 2.05 times.
The researchers suggest that night lighting can be considered using ordinary bulbs or long-wavelength light for illumination, and try not to use LED lights.
3. More likely to be overweight and obese
In addition to cancer, studies have shown that exposure to nighttime lights can also make people fat!
A 2019 study published in the Journal of Internal Medicine of the United States Medical Association followed 43,722 women and found that people who turned on the lights or TV while sleeping were more likely to gain weight.
These women had a 17 per cent higher risk of gaining more than 5 kilograms of weight and a 22 per cent and 33 per cent higher risk of developing sudden overweight or obesity compared to those who slept without a light source in the house.
It was found that the risk of weight gain increased as long as artificial light sources were exposed while sleeping. Researchers say it may be because light interrupts sleep, reduces sleep duration and quality, and increases human desire to find high-energy foods. At the same time, light exposure will also directly inhibit the production of melatonin in humans, disrupt the biological clock, etc.
4. Cause vision loss in the eyes
Lian Wenrui, an attending physician of the Department of General Medicine of Shanxi Provincial People's Hospital, said in an article published in Popular Science China in 2021 that some people keep the lights on at night, which makes too strong light pass through the eyelids during sleep, which may affect the ciliary muscles of children's eyes during sleep, and the ciliary muscles cannot be rested and relaxed, and they are prone to myopia.
There are light-sensing cells on the normal retina, which can sense the intensity of light, and the brain receives signals to regulate the secretion of hormones such as melatonin in the body. If some individuals have a high sensitivity to light, circadian rhythms can be disrupted, leading to disease.
5. May cause other chronic diseases
According to Dr. Lian Wenrui, many studies have found that nighttime light can affect the cardiovascular system, endocrine system, and nervous system. Excessive light may lead to obesity, high blood pressure, dyslipidemia, dementia, diabetes, insomnia, etc., all of which may be related to night light.
Artificial light at night disrupts these photoperiod signals, causing effects on humans and wildlife, including sleep disruption, physiological stress, and increased risk of cardiovascular disease.
Studies have also shown that people who don't use screen-screen phones sleep better and are more likely to get enough sleep than when they use them.
These are common nighttime lights
Night lights, in fact, are night lights, with a wide range, and the common lights in life that will affect people's sleep are as follows:
1. Desk lamps, night lights, hanging lights, wall lamps, LED lights, etc.
2. Outdoor street lights, car lights, etc.;
3. Watch the light emitted by electronic products such as mobile phones, tablets, computers, TVs, etc. before going to bed.
Many people are accustomed to turning on a small night light when they sleep, believing that the light can bring a sense of warmth and security, but it seems that sleeping with the night light on may affect their health. Sleep in the dark.
It's better to sleep this way
1. Reduce the lighting time of desk lamps, night lights, hanging lights, wall lamps, etc. at home.
2. Avoid outdoor street lights, car lights, etc., use more blackout curtains at home, and you can also use eye masks to reduce external interference.
3. Choose the right light color, avoid using too bright white or blue light, and choose amber, red or orange light.
4. Dim the ambient lights 2-3 hours before bedtime and leave the lights on when you go to bed.
5. 30 minutes to 1 hour before bedtime, it is recommended to reduce the viewing of electronic products, such as mobile phones, tablets, computers, TVs, etc., and remove unnecessary light sources in the bedroom.
Source: Health Times
Editor: Cheng Qian
Editor-in-charge: Wang Bo
*Please indicate the source of the reprint from "Shanghai Changning"