Brain Link. Sunlight is vitally important for your brain. Rays entering through your eyes help recalibrate the circadian-rhythm clock in your brain so it “keeps correct time.” Without a well-functioning clock, your brain and body could become confused and might not know when they were supposed to do their jobs, sleep, or wake up. Exposure to the ultraviolet radiation in sunlight has both beneficial and deleterious effects. Excessive can be defined as inappropriate amounts of exposure to the sun’s ultraviolet radiation (UVR) for your skin type. Beyond the known effects related to Vitamin D production and calcium utilization, sunlight turns on internal chemical reactions and stimulates enzymes to work more effectively. Healthy exposure to sunlight can boost the production of serotonin, a hormone that impacts mood. Brain plasticity and depression, regulated in part by Brain-Derived Neurotrophic Factor (BDNF), show a correlation with the amount of ambient sunlight. Debates continue about how much sunlight is optimum, although avoiding sunburn is not up for debate. Flood your home with sunlight and be prudent about your own exposure.
May the sun always shine on your window pane. May a rainbow be certain to follow each rain. —Irish Wish
You might want to think of sunlight as the good, the bad, and the ugly. Sunlight allows you to live on Planet Earth. Sunlight can damage or kill you. Sunlight or solar radiation is the electromagnetic radiation or energy from the sun that is visible at earth’s surface. The amount of sunlight is dependent on the extent of the daytime cloud cover. The sun never sleeps. Even at night or on a cloudy day, the sun is shining somewhere. The only star in Planet Earth’s solar system, Old Sol—a nickname—is the most important source of energy for life on earth.
Plasma-Universe.com has described the sun as a huge ball of hot plasma consisting mostly of three-fourths hydrogen and the remainder as helium ions, with lesser amounts of oxygen, carbon, neon, and iron. Over 800,000 miles (1.3 million km) in diameter, it radiates energy from fusion reactions in its core.
One Sun warms and enlightens the world; two suns would destroy it. —Shahab al-Din Yahya ibn Habash Suhrawardi
NASA has described what appears to be jet streams or rivers of hot electrically charged gas flowing beneath the surface of the sun. The corona, the outermost part of the sun’s atmosphere, extends millions of kilometers into outer space, creates solar winds, and is most easily seen during a total solar eclipse. Coronal mass ejections that blow out from the sun can interfere with the Earth’s magnetic fields, which can cause the colorful auroras that swirl around at the North and South poles.
Theoretically, if the Earth suddenly stopped moving, it would be a catastrophe as the atmosphere would still be moving at the original speed of the Earth’s rotation. Everything would be swept off the land: topsoil, rock, trees, buildings, creatures—and people. Fortunately, there is no chance of this actually happening as the gravity on Planet Earth is stronger than its spinning motion.
Planet Earth is spinning around the sun at a speed of 67,000 mph (107,000 km/h). —Cornell University
View the Educational Video #7. If possible, stand and walk in place for at least a portion of the video to increase blood flow to your brain.
Behind the cloud the sun is still shining. —Abraham Lincoln
When hydrogen is changed into helium, the chemical reactions create both light and heat that leave the sun and go out into space as sunlight. It takes about eight light- minutes for sunlight to reach earth. Sunlight is composed of electromagnetic particles that travel the universe in waves of energy known as the electromagnetic spectrum. Categories include radio waves (long length), microwaves, infrared, visible, ultraviolet, X-rays, and gamma rays (short length). According to Sciencing.com, ultraviolet, X-rays and gamma rays can damage living tissues—microwaves can cook them. The effects of electromagnetic radiation (EMR) on the human body have been seen in the bombing of Hiroshima and Nagasaki. Also, in the nuclear accidents of Chernobyl, Ukraine, Fukushima, Japan, and elsewhere.
Ultraviolet rays consist of UVA, UVB, and UVC radiation. UVC is absorbed by the Earth’s atmosphere and does not pose a health risk. However, artificially produced UVC radiation (as in some tanning lights and welding light) can be dangerous. The human eye is sensitive only to a subset of the sun’s electromagnetic spectrum, i.e., the visible light or color portion, located between ultraviolet rays and infrared lights. The colors in visible light are red, orange, yellow, green, blue, indigo, and violet—just as seen in a natural rainbow.
The Sun is the most important thing in everybody’s life, whether you’re a plant, an animal, or a fish, and we take it for granted. —Danny Boyle
Although the sun may be 93 million miles away, it is so fiercely hot that its light and heat can cause the scorching of anything on the earth’s surface. At its surface, the sun’s temperature is estimated to be about 10,000 degrees o F (5,600 o C). According to Space.com temperatures at its core can reach more than 27 million degrees o F (15 million o C). The corona, the outermost part of the Sun’s atmosphere and usually hidden by the bright light of the Sun’s surface, is hotter than the sun’s surface. Corona temperatures range from 1.7 million o F (1 million) o C to more than 17 million o F (10 million o C).
This is important to realize as rays from the sun can damage your brain and your skin and even kill you. For example, recently the temperature in Death Valley was reported at 128 degrees F. Apparently, a motorcycle rider—attempting to cross the desert in the daytime rather than at night—never made it. He died from heat exposure and dehydration.
UV radiation in sunlight constitutes about 10% of the total electromagnetic radiation output from the sun: 95% is UVA and 5% is the slightly stronger UVB. UV rays are not blocked by clouds so you can still get too much UV exposure even on a cloudy day. Unprotected excessive exposure to sunlight that is defined as inappropriate amounts for your skin type, can cause problems due to this UV radiation. Interestingly, UVA rays can pass through glass, while UVB rays cannot. This means you cannot get a sunburn through glass. UVA rays, although slightly weaker, can still create damage.
Old Sol sends its heat energy to earth usually in the form of light, and many of its rays are in the ultraviolet spectrum. The transfer of heat in this way is known as thermal radiation. —Wanda Thibodeaux
Sunlight is responsible for keeping your brain’s internal circadian-rhythm clock on time. This clock regulates biological processes, such as sleep, wakefulness, and hormone production. Without a well-functioning clock, your brain and body could become confused and might not know when they were supposed to do their jobs, sleep, or wake up. Circadian rhythms have a period close to 24 hours and are synchronized daily by environmental time cues. In humans and other mammals, this clock consists of a group of cells in the brain’s hypothalamus known as the suprachiasmatic nucleus (SCN).
The SCN uses signals from the eyes to keep the human circadian rhythm in sync with the sun. Rays entering through your eyes help recalibrate the circadian-rhythm clock in your brain, so it keeps correct time—resetting or recalibrating this 24-hour biological clock on a regular basis. Known as entrainment, this process occurs when natural sunlight enters the eyes triggering light-sensitive cells in the retina to send electrical signals to the SCN. These electrical signals activate the SCN, and the circadian-rhythm clock then wakes up the body organs, notifying the pineal gland to stop secreting the hormone melatonin. Many people are unaware that their ability to sleep at night and be awake in the day is controlled primarily by their internal circadian rhythm clock.
No one has an exclusive opportunity. When the sun rises, it rises for everyone. —Chinese Proverb
The production and release of melatonin in the brain is connected to time of day. It increases when it’s dark and decreases when it’s light. At sundown, the SCN tells the pineal gland to release melatonin, which helps to promote a sense of being sleepy and helps regulate biological rhythms. Melatonin production tends to decline with age. This can be one factor that makes elderly people struggle with sleeping well.
As mentioned in Module #4, some teenagers experience what is known as a Sleep- Phase Delay. This means their melatonin levels naturally rise later at night as compared with others. The teenagers feel alert later, making it difficult to fall asleep before eleven o’clock—or even midnight. Sleep deprivation, compounded by early school start-times, can negatively influence life in general and learning in particular for these individuals. Keeping lights dim as bedtime approaches, turning off electronics an hour before bedtime (or wearing special glasses to block LED light), along with exposure to bright light as soon as possible in the morning may be helpful.
The Earth would die if the sun stopped kissing her. —Hafez
The sun provides an almost unbelievable array of benefits to Planet Earth. Following is a list of just a few of them.
1) Provides light by day so creatures and humans can see.
2) Maintains the brain’s internal circadian rhythm clock.
3) Helps plants with photosynthesis. Chlorophyll absorbs sunlight and turn it into chemical energy that in turn changes water and carbon dioxide into glucose.
4) Can lower the level of viable bacteria that live indoors in dust.
5) Provides some light at night as the moon reflects between 3-12% of the sunlight that strikes it.
6) Enables the body to make Vitamin D from cholesterol in skin cells, which helps your body absorb calcium—essential for strong bones
7) Provides heat that makes life on earth possible.
8) Keeps water in a liquid state so it can be used to generate electricity from hydroelectric action.
9) Helps boost Serotonin, lower levels of which are associated with Major Depressive Disorder (MDD) with Seasonal Pattern, formerly known as Seasonal Affective Disorder (SAD).
10) Can boost immune system function.
11) When sunlight hits the ocean surface, about 95% is transmitted through the water where plankton and other ocean contents eventually absorb it, etc. The zone of penetration of sunlight into the water column is called the euphotic zone.
It is no secret that the moon has no light of her own, but is, as it were, a mirror, receiving from the influence of the sun. —Vitruvius
When sunlight shines on human skin, the skin is enabled to make vitamin D, often referred to as the ‘sunshine’ vitamin. Vitamin D is a group of fat-soluble secosteroids, derived from steroids. Vitamin D₃ is believed a particularly important compound in this group. Estimates are that many adults are deficient in vitamin D. This deficiency has been linked with low energy, brain fog, low mood, aches and pains, difficulty sleeping, cancer, osteoporosis, and muscle weakness. Vitamin D assists with:
1) Intestinal absorption of calcium, magnesium, and phosphate, etc.
2) Muscle function including recovery from physical exercise
3) Activating the hormone leptin that helps control appetite
4) Supporting immune system function
5) Lowering insulin and helping with insulin resistance
6) Maintaining good lung function
7) Lowering a risk for colon cancer and heart disease
The American Cancer Association suggests obtaining vitamin D from a supplement since rather sunlight itself. That would not increase a skin cancer risk from excessive ultraviolet radiation from sunlight. Typically, it is a more reliable way to get the amount you need. Only a few foods contain vitamin D. Some people like cod liver oil; others prefer Vitamin D 3 by capsule. Those with darker skin may require 1.5 as much vitamin D as compared with individuals with fair skin since darker skin blocks UVB rays from triggering the skin to produce Vitamin D.
To love and be loved is to feel the sun from both sides. ―David Viscott
Sunlight is vitally important, so much so that insufficient amounts can cause serious problems. You may have heard of Non-24-Hour Sleep Wake Disorder or Non-24 for short.
According to the Sleep Foundation, the majority of individuals who are blind have some sunlight perception and circadian rhythms that are synchronized to a 24-hour day-night cycle as in the sighted. Non-24 is common in totally blind individuals because sunlight cannot get to the retina. Thus entrainment (recalibration) of the brain’s circadian rhythm clock does not occur and the cycle of the clock begins to lengthen beyond the usual 24-hours and a few minutes. This can be disruptive to a person’s life causing fluctuating periods of good sleep followed by periods of poor sleep and excessive daytime sleepiness.
Where there is sunlight, the doctor starves. ―Flemish Proverb
Jetlag is a term for what happens when the brain’s 24-hour circadian rhythm clock becomes disoriented. It is in conflict with a person’s normal sleep patterns as the brain scrambles to adjust to crossing many different time zones in fairly rapid succession. For some, this readjustment or recalibration can take a day for every time zone crossed, often causing problems with effective thinking and efficient performance.
Similar symptoms can occur when a person works rotating shifts or when sleep times differ radically on weekends and the brain tries to adapt to shorter, longer, or irregular hours. Individuals who have a new born baby in the house often find their sleep patterns very disrupted and have been known to describe it as a “type of jetlag.”
Hope is like the sun, which, as we journey toward it, casts the shadow of our burden behind us. —Samuel Smiles
Major Depressive Disorder (MDD) with a Seasonal Pattern, formerly known as Seasonal Affective Disorder (SAD), is characterized by recurrent episodes of depression in late fall and winter, alternating with periods of normal mood the rest of the year. Researchers at the National Institute of Mental Health were the first to suggest that this condition was a response to insufficient amounts of sunlight and experimented with the use of bright light to address the symptoms. Scientists have identified that the neurotransmitter serotonin may not be working optimally in many people who experience this disorder.
Although each individual with MDD has different experiences, symptoms may include these.
If you experience MDD—a subset of major depression—NAMI suggests that thinking ahead to reduce symptoms may be helpful. For example:
Too little sun can be detrimental for those who live in northern areas with diminished levels of sunlight during portions of the year (e.g., North and South Poles or within the Arctic Circle). Researchers studying Major Depressive Disorder found that nearly 10% of residents in Fairbanks, who had lived in Alaska for three years or more, met the criteria for MDD. It occurred more often in females by a ratio of 3:2 and was less prevalent among residents over the age of 40. Studies of residents in northern Switzerland showed that nearly 8% met criteria; in northern Finland it was 9%.
Most of the shadows of this life are caused by standing in one’s own sunshine. —Ralph Waldo Emerson
Listen to Chapter 9 of Just the Facts audiobook. If possible, walk around the room while you listen or walk in place.
Rise above the storm and you will find the sunshine. ―Mario Fernandez
The sun gives off a natural form of blue light waves that appears blue turquoise in the visible light spectrum. When the sunlight travels through the atmosphere, the high- energy blue waves crash into the air molecules, scattering blue light everywhere—making the sky look blue. Natural blue light waves help you feel alert, be in a pleasant mood, strengthen your immune system, and regulate your circadian rhythm. Filters in the human eye are better able to filter out this natural source of blue light, although wearing dark glasses when in bright sunlight is recommended for prevention.
So, what is the problem?
Technology!
The closer blue light waves fall toward the Blue-Indigo end of the visible spectrum, the more risk they pose to your eye health. These are the type of blue light waves that emit from the LED screens of computers, smartphones, and tablets—among others. These highest energy blue light waves can cause the most damage to your macula. With the huge increase in LED screen time in recent decades, human eyes are being asked to handle vast amounts of artificial blue light waves, putting a serious strain on vision.
Prolonged exposure may cause retinal damage and contribute to age-related macular degeneration. These shorter artificial electronic blue light waves flicker more easily than natural blue light waves. They are also longer, creating a glare that can reduce visual contrast and affect sharpness and clarity. It may be one of the reasons for eyestrain and headaches along with physical and mental fatigue caused by many hours sitting in front of a computer screen or other electronic device.
It is likely advisable to wear special blue-light blocking glasses or screen protectors when using electronic devices. Again, prevention beats cure!
I always knew that someday I would once again … walk in the sunshine as a free man. ―Nelson Mandela
In addition to life-giving benefits, the power of sunlight can be seen in a variety of undesirable outcomes.
What is life? It is the little shadow which runs across the grass and loses itself in the sunset. ―Crowfoot
The process whereby skin color is darkened from exposure to the sun’s ultraviolet radiation or from artificial sources has been misunderstood. The increase in the skin pigment melanin, which causes the tan color change, is a sign of damage.
There is no safe way to tan and no such thing as a safe tan—either from natural sunlight or from artificial sources such as sun lamps and tanning beds. It can be particularly unhealthy when obtained from an artificial (versus natural) UV source. —American Academy of Dermatology
Human beings can also be exposed to artificial sources of UV rays in the workplace. These can include plasma torches and welding lamps used in industry, and mercury- vapor lamps if the outer bulb breaks.
Sunlamps and sunbeds (e.g., tanning beds and booths) are also sources of UV rays. The amount and type of UV radiation someone is exposed to from a tanning bed (or booth) depends on the specific lamps used, how long a person stays in the bed, and how many times the person uses it. The Skin Cancer Foundation has pointed out that high-pressure sunlamps used in tanning salons generate UV doses up to 12 times that of the sun. Clients are 2.5 times more likely to develop squamous cells and 1.5 times more likely to develop basal cell carcinomas.
UV tanning beds are classed as Class #1 human carcinogens. —World Health Organization (WHO)
There is a move in some countries to prohibit the use of tanning lights and beds by anyone under the age of 18. Studies estimate that the risk increases significantly for people who use a tanning bed before the age of 35. Your risk of melanoma is higher if you started indoor tanning as a teen or young adult. A first exposure to tanning beds in one’s youth can increase one’s melanoma risk by 75%.
The majority of melanomas—the worst forms of skin cancer and responsible for the most skin-cancer related deaths—are estimated to be caused by UV exposure. —US Surgeon General
View the short Birds ‘n Brains video #7. Stand and move around or walk in place at least part of the video.
Clouds in the sky enable us to see beautiful sunsets and dawns. The same is true in our lives. ―Old Proverb
Some people are making such thorough preparation for rainy days that they are not enjoying today’s sunshine. —William Feather
Dark wrapped-around sun glasses help reduce side sunlight and blue light waves that reach the retina. Good quality sun glasses that allow you to read can prevent having to remove them every time you need to read something. Are you wearing a sun hat when you are out in bright sun in addition to dark glasses and effective sun screen on exposed skin? Bright sun is linked with macular degeneration, an eye condition to be prevented if at all possible. It is also linked with damaging the skin and increasing a risk for skin cancers.
Any type of light—blue light waves, especially—suppresses melatonin production and increases alertness. An hour before bedtime, turn off all electronic equipment with blue-light-emitting diodes (LEDs)—unless you wear special glasses that block the blue light from entering your eyes. Suppressing melatonin is exactly what you want to avoid when you need sleep.
If you have a night light on in your bedroom or clock or other equipment that can emit blue light, wear eye protectors to avoid suppressing melatonin if you wake up during the night.
Studies suggest that sitting for hours under fluorescent-light tubes that emit blue light waves can cause headaches and negatively impact one’s overall health.
If possible, replace fluorescent-light tubes that emit blue light waves with natural- light tubes.
Do you see how the sky holds the sun? In a powerful but effortless way that’s shows off her beauty and strength. ―J. A. Anum
Concentrate on Module #7 during this entire week or for longer if needed. Reread the sections, review the videos, and relisten to the Just the Facts audiobook excerpts. It takes the average adult four times through to really absorb new material and practically apply it.
Drink plenty of water to keep your brain hydrated and able to generate the mental energy you need, especially when doing physical exercise or being out in sunlight.
Too little sunlight is unhelpful. Too much sunlight can be damaging. Obtain sunlight appropriately and in balance. Avoid exposure to hot mid-day sun if at all possible. Managing your exposure to sunlight can be lifesaving.
Even after all this time the sun never says to the earth, “You owe me.” Look what happens with a love like that—it lights the whole sky! —Hafez
