Sunlight brings countless benefits to our body! |

How does sunlight melt fat?

“When waves of blue sunlight penetrate our skin and reach fat cells just below its surface, it causes adipocyte contraction, which reduces their size, thanks to which adipose tissue is reduced” – explains the author of the study [ 1] Dr. Peter Light from the University of Alberta.

The results of this discovery lead to the conclusion that insufficient exposure to sunlight during the fall and winter months may favor fat storage for some of us. This discovery could pave the way for new weight loss strategies based on light therapy to treat obesity and diabetes. Dr. Peter Light points out that more research is needed into the effects of the sun on our functioning so that sunlight therapy can be recommended for people to improve metabolic health.

Light regulates our circadian rhythm, affecting every aspect of our lives!

Your eye is not only a camera through which you see the world. There is an additional visual pigment in your eyes, melanopsin, discovered quite recently in the early XNUMXs, which is involved in “non-visual” responses to light, such as the regulation of biological rhythm. Melanopsin is sensitive to a blue light source which keeps your internal circadian clock in perfect sync with the rhythm of the day and night.

Your central brain clock is the suprachiasmatic nuclei – located in the front of the hypothalamus, which regulate the level of activity depending on the time of day, responding to light stimuli received by photosensitive retinal ganglion cells – intrinsically phoptosensitive retinal ganglion cells, ipRGSs for short (learn this name and tell your friends about it) , watching their expressions 😉). It is in these cells that melanopsin is found. Human metabolism is very closely related to nature, and circadian rhythms synchronized with the cycle of light and dark appeared in humans to increase their chances of survival.

In 2017, three American scientists (Jeffrey C. Hall, Michael Rosbash, Michael W. Young) received the Nobel Prize for the discovery of the molecular mechanisms responsible for the circadian rhythm. The science of the influence of time on our body and its processes is called chronobiology. Our life depends on various biological clocks, both internal and external.

The internal biological clock adjusts our physiology to the different phases of the day, regulating our hormone levels, body temperature, metabolism, blood pressure and even well-being depending on the day or night hours. Scientists compare the functioning of our body in a circadian rhythm to a symphony orchestra, where all biological processes work together like different instruments in an orchestra. The main conductor of this inner “orchestra” is the circadian rhythm, where the term circadian comes from the Latin words circa for “around” and diem for “day”.

Irregular meal times, especially eating late in the evening just before going to bed, working on various shifts (morning, afternoon, nightly), frequent travel to other time zones, inactivity outside, spending time in front of the computer in the evening, insomnia – all this can cause dysregulation our natural circadian rhythms. Your body is billing this modern lifestyle: daytime fatigue, insulin resistance, metabolic diseases, inflammation, obesity, and weight loss issues, to name just a few, and the list goes on.

Below is a graphic showing all possible complications and health problems that can develop in each of us in a few or several years, when we do not follow the daily rhythms set by nature.

Of course, everyone’s sensitivity to these stressful conditions is different. I know many people who have worked all their lives in three shifts, including night shifts, and it did not drastically affect their health. However, you should know that night shift work is particularly dangerous and was classified in 2007 by the International Agency for Research on Cancer (IARC) as promoting the development of cancer. Two of my colleagues died of cancer after working in three shifts for many years. One was healed, but the doctor forbade her to work on the blinds so as not to provoke a recurrence of the disease. 

The danger of overusing blue light after dark

Modern LED lighting in our apartments, on the streets or in computers is much brighter than old light sources, such as energy-consuming bulbs from 20 years ago, candles, kerosene lamps, because it contains more light in the blue spectrum. Sometimes a low level of this type of lighting in the evening is enough to disturb our biological clock, because naturally blue light occurs outside from morning to noon. Sitting late at night in front of a laptop or using a cell phone, our brain thinks it’s daytime.

Melatonin is called the “night hormone” and is secreted into the bloodstream by the pineal gland in response to a signal sent by the suprachiasmatic nucleus. Melatonin levels are not only affected by our main biological clock. Its secretion can be stopped or limited by light, mainly blue light, coming from our cells, laptops or TV sets. Scientists call this phenomenon „light pollution”which is light pollution. Not only does it adversely affect the circadian rhythm, which may shift, but can also contribute to insomnia and related health problems by failing to regenerate at night.

Sleep disorder expert Dr. Steven Lockley of Brigham and Women’s Hospital in Boston warns that sitting regularly late into the evening with the lights on could cause your internal clock to misalign and completely disrupt your system. Everyone has a different tolerance to blue light in the evening hours. There are people whose biological clocks work flawlessly and have a well-tuned circadian rhythm that watching TV or reading on a tablet in the evening will not affect their ability to fall asleep.

Neurobiologist Steven Lockley emphasizes that some people have exceptional biological sensitivity to light, so they should avoid its intense source even for several hours before bedtime. Insomnia specialists have noticed that in photosensitive people, even relatively dim light when it comes close to the eyes can limit or delay melatonin secretion and thus prevent you from falling asleep quickly.

Bright light also raises our body temperature and heart rate, which drop to their lowest values ​​at night. These light-induced changes are short-lived and slight, but they can adversely affect our body if the situation is repeated regularly.

Excessive use of blue light sources after dark may raise the level of cortisol, which blocks the release of melatonin. In addition, some people get hungry when instead of going to sleep they browse the computer at night. These practices obviously sabotage successful weight reduction. If these arguments do not convince you to give up the nightlife lifestyle, maybe the information that blue light can cause skin aging faster will be more important to you 😉

Instead of LED lighting after dusk, it is worth considering the use of candles whose light is warmer and less intense. If someone still has to or wants to use a cell phone or laptop, watch Netflix after dark, they can install filters that reduce blue light and change the color of the light to a warmer one (I have the f.lux program in my laptop) or buy special glasses that block blue light. For super light sensitive people, it is not recommended to use electronic devices after sunset.

Why is exposure to a natural light source important?

Most of the blue light spectrum occurs in the morning, along with the rising sun, and lasts until noon. This light has a stimulating effect on us, thanks to which the level of melatonin – the sleep hormone in the body decreases, and it increases the level of cortisol, which is needed in the morning to start the day vigorously. This is how nature works, and our circadian rhythm is also dependent on the morning dose of light.

If you have difficulty waking up in the early morning, experts advise you to go outside, preferably around sunrise (7am to 00am) to expose yourself to natural sunlight. On cloudy days, the exposure time should be about 9 minutes, on sunny days, even a few minutes are enough for the bright light to be recorded by melanopsin in ipRGSs cells and fulfill its stimulating task. Note that the intensity of natural light outside is much greater than that inside our homes or workplaces.

In the living room, the light intensity is about 50 lux [lux], in the office there is a little more – from 100 to 500 lux. Occupational safety agency Heallth and Safety Executive recommends 200 lux for the workplace, and when no perception of detail is required (in most factories) – that’s only 100 lux. Nobody takes into account our circadian rhythms in these light recommendations. People aware of the influence of light, its color and intensity postulate to use a dynamic type of lighting that mimics the natural circadian rhythm.

Here are other examples – on a cloudy day, the light intensity measured in lux is 1000. On a clear, sunny day, the light dose is from 10.000 to 25.000 lux. Direct sunlight, a very sunny day, is a huge dose of lux: 32.000 – 130.000. A very dark and cloudy day is a paltry 100 lux. The full moon on a clear night is only 0.27 lux. You can install the lux measurement application on your smartphone and check the level of light intensity in different places and at different times of the day. I use the application: Lux Light Meter.

Scientists help people with insomnia by recommending them contact with daylight in the morning. It has been reported that people who received a light dose between 18 a.m. and 45 p.m. fell asleep after 20 minutes, compared to XNUMX minutes for those patients who had contact only with a weak light source while inside buildings. They also slept for about XNUMX minutes longer, and the more light they provided during the day, the longer their deep sleep became, which made them feel well rested.

What is social jet lag?

Professor Till Roenneberg of the Ludwig Maximilian University in Munich is a specialist in chronobiology who warns people not to stay indoors for too long where there is not enough natural light. It is needed for our biological clock to be ticking flawlessly. The sun should be present in our lives as it has been for millennia. Humans have evolved under the open sky, so to this day our bodies respond positively to exposure to sunlight, and our circadian rhythms work perfectly.

Till Roenneberg is the author of the concept of “social jet lag” [2]. He studied the sleep times of more than two hundred thousand people around the world and found that only 13 percent of the population did not experience social jet lag, while others had their circadian rhythms shifted by an hour, two or more a week. It looks like you delay going to bed during the weekend and stay active until 1 a.m. or even longer, while sleeping fully. However, when Monday comes – you are brutally awakened from sleep at 6 am, that is, you get up when your body wants to sleep. Roenneberg describes it with these words: “This behavior is comparable to a Friday night flight from Paris to New York or from Los Angeles to Tokyo returning home on Monday. It is quite like the classic jet lag when time zones change due to air travel, so we called it social jet lag. “

Professor Till Roenneberg warns that by exposing to changes in the social time zone, the risk of being overweight or obese increases with each hour of shifting the circadian rhythm by about 33% [3]. At the same time, it emphasizes the importance of the regularity of our daily routine and taking care to live in accordance with our owl or lark chronotype.

Light and our well-being

During the winter months, approximately 3 percent of Europeans, 10 percent of North Americans and 1 percent of Asians suffer from SAD (seasonal affective dissorder) – that is, seasonal mood swings, depressed mood, and depressive states of varying severity associated with a reduction in the dose of daylight. This affliction is more common in women. Perhaps you belong to those people who quickly fall into the pits in winter, and their mood worsens when it is gray and dark outside, and there is no sun.

It has been found that people with a more general form of depression tend to lose their appetite while suffering from insomnia, while people with SAD sleep longer than during the summer months and tend to overeat carbohydrates. In these cases, light therapy with an intensity of 10.000 lux or long walks outside, even in a cloudy sky, can be helpful.

Most people’s moods also show a strong circadian rhythm. We wake up in a bad mood, but over time our attitude towards life, people, the world improves and we become more cheerful. In the evening, my well-being worsens slightly again. Intense morning light has an anti-depressant effect, speeds up the circadian rhythm and increases concentration in the same way as drinking two cups of coffee. Sunlight releases the production of serotonin in our brain, and endorphins are also produced when sunlight hits the skin. Remember how you feel on a beautiful sunny day, and how you feel during the week when it is constantly raining and dark. Do you have fluctuations in humor and energy depending on the weather and the intensity of the light?

Very important, the latest scientific discoveries that shed new light on … sunlight

Near infrared rays emitted by the sun can penetrate our skin and reach a depth of 1 cm to even 8 cm into the skin layers. You will feel them on yourself from the morning hours between 10:00 and 11:00 on a sunny day, because they give you a feeling of pleasant warmth. These rays reach the mitochondria, which are energy factories and stimulate the production of melatonin, which has an antioxidant effect and protects cells against excess free radicals that arise in the process of energy production [4] [5].

This type of melatonin is produced inside the cells and has nothing to do with the melatonin secreted into the blood by the pineal gland in the evening, which helps us fall asleep. It is estimated that the daily production of melatonin is as high as 95%, while the night production is only 5%.

Scientists report that near-infrared rays stimulate the production of melatonin during the day, which is twice as powerful as an antioxidant than vitamins E and C and is more powerful than glutathione, which until now was considered our most important antioxidant, protecting our bodies against free radicals and reactive oxygen species. With this knowledge, you can consider using the sun to prevent diseases that are rooted in mitochondrial disorders such as cancer, inflammation, dementia, and diabetes.

You don’t need to be directly exposed to the sun to feel the positive effects of near-infrared radiation. It turns out that green spaces in the city, such as parks or forests outside the city, reflect this type of light and diffuse it over a large area. Studies have been conducted in which scientists proved that people living in green areas enjoy better health [6]. I wrote about the beneficial effects of walks in the woods in my first article on and I encouraged you to use the benefits of shinrin-yoku for free.

Heliotherapy and sun worship

Over the centuries, different civilizations, separated by thousands of kilometers of land and oceans, have worshiped the sun as an important deity or god, recognizing its life-giving power.

Ancient medics in China and India already understood the great potential of treating various diseases with sunlight. They recommended sun baths and compresses made of plants that had been exposed to sunlight. This form of treatment is called photochemotherapy.

Sun treatment is known as heliotherapy, and the discovery of the beneficial effects of the sun was awarded the Nobel Prize in 1903, which was awarded to the Danish doctor Niels Finsen. He proposed treating skin diseases and rickets in children with the sun’s rays.

The Swiss surgeon Auguste Rollier, inspired by the work of Finsen, built a clinic high in the Alps in Leysin, with patients’ beds outside or by large windows. They treated tuberculosis, smallpox, lupus and non-healing wounds with sun exposure.

Summation

We currently have an ambivalent approach to the sun. We are scared of the harmful UV radiation (ultraviolet) that can cause skin cancer, and at the same time exposure to the sun to produce vitamin D. Some of you never go out on sunny days without using sunscreen, others completely they do not care and use the sun wisely or spontaneously.

This article is an attempt to look at the sun and sunlight from a completely different angle, showing how much our organisms are dependent on the changing rhythm of the day and night, how connected we are with nature, although we do not seem to remember it every day. It is said that some people now spend about 93% of their lives indoors. What will the health effects of this be for future generations?

Remember your childhood and how much time you have been active outside, and how is it with you now? Perhaps you suffer from dysregulation of circadian rhythms, insomnia, low mood, problems with night snacking and morning fatigue. Look at your life in terms of exposure to the type of light, maybe here is a solution to your pains and frustrations.

If you are interested in this topic and you would like to deepen your knowledge on these issues, I suggest reading the book by Linda Geddes “Chasing the Sun”, which I used for this article. I also recommend the film documentary «Chronobiology. How our biological clock works ». If you know English, you can watch a lecture on the effects of sun and sunlight on our life and health by Dr. Roger Seheult, who is incredibly substantive and interesting.

If so far you have not paid attention to how much time you spend in the open air, after reading this article you can change your habits and attitudes. Do not forget to walk outside, leave the apartment today and go to the park! Spring is the best time of the year to start spending more time outdoors. The sun is shining more and more every day, nature comes to life, and you also enjoy it. Wake up! I wish you nice, sunny days, a lot of good humor, health and effective fat-melting thanks to the sun 😉, after all, science cannot be wrong.