Human Skin Didn't Always Fear The Sun, Not Until A Huge Change 10,000 Years Ago
The Sun and people have a tumultuous connection.
People enjoy the sun, but they also become hot. Your eyeballs sweat into them. Then there are all the rituals associated with protection: sunscreen, hats, and sunglasses. Your skin will react angrily with a sunburn if you are out in the sun for too long or haven't done enough safety measures. Heat comes first, followed by pain and then regret.
Was the fear of what the Sun will do to one's body always as intense? I can tell you the quick answer is "no," and they didn't need to be, as a biological anthropologist who has researched how monkeys adapt to their surroundings. Skin has withstood the Sun for ages.
Between you and the world, Skin
Humans developed in the Sun's rays. People's life were characterized by sunlight, which warmed and led them through the days and seasons. Most of Homo sapiens' prehistory and history was spent outdoors, primarily in the absence of clothing. The main point of contact between our ancestors' bodies and the outside world was their skin.
The skin of humans is suited to the environment it is in. When they could, people sought refuge in caves and rock shelters, and they became quite adept at building lightweight, portable shelters out of wood, animal skins, and other acquired materials.
They congregated at night and most likely wrapped themselves in fur "blankets." However, during the busy daylight hours, individuals were outside, and their only real clothing was their exposed skin.
Skin reacts in various ways to regular exposure to the Sun throughout a person's lifespan. By developing additional cell layers, the epidermis, the skin's top layer, thickens.
In most humans, the skin gradually darkens as specialized cells begin to create eumelanin, a protective pigment.
This extraordinary molecule absorbs the majority of visible light, giving it a very dark brown—almost black—appearance. Additionally, eumelanin absorbs harmful UV rays.
Different levels of eumelanin are produced by individuals based on their genetic makeup. Some people start out with a lot and can create a lot more when their skin is exposed to the sun, while others start out with less and may make less.
My studies on the development of human skin pigmentation have demonstrated that prehistoric people's skin tones were adapted to regional environmental factors, particularly to ultraviolet light concentrations.
People that were exposed to intense UV rays year-round, such as those found close to the equator, had darkly pigmented, highly tannable skin that could produce a lot of eumelanin.
People who lived in areas with weaker and more variable UV exposure, such as much of northern Europe and Asia, had lighter skin with a lower capacity to create protective pigment.
Our distant ancestors didn't move about much during their lives, having just their feet to transport them.
By creating more eumelanin and becoming darker in the summer and then shedding some pigment in the fall and winter when the sun wasn't as intense, their skin adjusted to minute, seasonal changes in sunlight and UV conditions.
Because there was never a sudden shock of intense Sun exposure, unpleasant sunburns would have been extremely uncommon, even for persons with lightly colored skin. Instead, over the course of weeks and months of sun exposure, the top layer of their skin would have gradually thickened as the Sun grew stronger during the spring.
The skin would not have been unharmed by today's standards, however, since dermatologists would be horrified by the leathery and wrinkled appearance of our ancestors' sun-exposed skin.
Skin tone altered with the seasons, just as the levels of sunlight, and skin swiftly exhibited aging. In many parts of the world, this is still true for individuals who have conventional lives that involve spending a lot of time outside.
Although there isn't any surviving skin from ancient times for scientists to investigate, we can surmise that the damage was similar based on how modern people are affected by sun exposure. Skin cancer from melanoma, which would be fatal to people in their reproductive years, can develop from repeated exposure to the sun, but this is unusual.
Prior to 10,000 years ago, when humans began to hunt and fish, they subsisted by gathering food. This is a drop in the evolutionary history bucket.
After people began to settle down and dwell in permanent settlements, humanity's relationship with the Sun and sunlight underwent significant alteration. Immovable building development was linked to farming and food storage.
Around 6000 BCE, a large portion of the global population began spending more time indoors and in walled towns.
While most individuals continued to spend the majority of their time outdoors, some chose to stay indoors if they could. When they did venture outside, many of them began to use sun protection.
A whole industry of sun protection emerged by at least 3000 BCE to produce garments, parasols, umbrellas, hats, tents, and other items that would shield people from the discomfort and unavoidable skin darkening caused by prolonged Sun exposure.
Although some of these, like the parasols and umbrellas of ancient Egypt and China, were first only used by the nobles, they started to be produced and used more often.
To protect their exposed skin, humans in some regions even created protective pastes using leftover plant and mineral materials that were the forerunners of modern sunscreens. Some still exist today, such as the thanaka paste that people in Myanmar still use.
In traditional agricultural civilizations, one notable result of these activities was that persons who spent the majority of their time indoors felt themselves privileged, and their lighter complexion served as a status symbol.
A "farmer's tan" was unattractive: Skin tanner was a punishment for hard outdoor labor, not a sign of a relaxing holiday. Throughout the world, from Great Britain to China, Japan, and India, browned skin came to be linked with a hard life.
In recent ages, as people have traveled farther and quicker and spent more time indoors, their skin has not kept up with their movements and way of life.
Your eumelanin levels are probably not properly matched to the local Sun conditions, so they can't protect you the way they might have for your prehistoric predecessors.
Everyone is susceptible to damage brought on by episodes of Sun exposure, especially after extended periods spent completely out of the Sun, regardless of whether they are naturally darkly pigmented or capable of tanning.
The "holiday effect" of quick, intense UV exposure is extremely harmful because a sunburn indicates skin damage that will never fully heal. It's similar to a bad loan that shows up years later as prematurely aged or precancerous skin.
There is no such thing as a healthy tan; in fact, a tan is a sign of damage from the sun, not a way to prevent it.
Although many people adore the Sun, we are not our ancestors. The way humanity interacts with the Sun has altered, and you must adapt in order to protect your skin.
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