When light makes aging visible

Aging is part of life. It's nothing new. But the fact that the sun not only makes us look radiant but can also noticeably age us might be a new concept for some. We are talking here about light-induced aging, also known as photoaging.

The next class reunion is coming up. The question is always the same: What are my old classmates doing now? And at every reunion, you look at people more carefully. Phrases like “Well, she still looks young” or “His wrinkles tell you his story” are commonplace. Anyone who has taken care of themselves and their health while using sunscreen over the past few decades will be pleased that their own wrinkles may not be as numerous nor as deep as those of other “old” friends this time around.

Why do we mention sunscreen here? It's simple: The use of suitable sunscreens is its own special type of skincare. UV filters help to protect you from beautiful yet harmful UV rays. Not only can sunburn be caused by excessive sunbathing, but long-term skin damage can accumulate over the years. Wrinkles are an outcome of this skin damage. It wouldn't be too much of a stretch to say that sunscreen is one of the best anti-aging products you can buy. UV radiation from the sun has an enormous influence on the extent and speed at which the skin ages.

Aging is part of life – that's just a fact. And time doesn't pass by without leaving a trace on our skin. “Natural” skin aging, as it is known, affects everyone. The first visible changes can be expected from around the age of 25. But here's a twist: Aging actually starts before we're even born. And everything we do to our skin in our younger years becomes visible later on.

The course of nature

There are many reasons why the skin ages, and the extent and progression depend on the individual. But nobody is spared. It starts with small laughter lines or crow’s feet, usually at the outer edge of the eyes. Our facial expressions are responsible for the first lines on our foreheads. What starts as a delicate, barely noticeable process becomes very noticeable as the years go by: Our wrinkles become deeper, longer and there are more of them. Gravity can also make itself felt as the skin starts to sag.

Let’s look at the natural changes in the three different skin layers: the epidermis, dermis and hypodermis. Each layer ages and produces different signs of skin aging as part of the natural aging process: Genetic factors play an important role in these processes in the skin's layers. What happens in the skin?

Epidermis
Cell metabolism slows and lipid production decreases.
Dermis
Aging weakens the elastic fibers and collagen. The boundary layer to the epidermis flattens out. The dermis begins to atrophy.
Hypodermis
The number and size of fat cells decrease, leading to more loss of volume. All the visible signs of aging are magnified.

But not all skin is the same. Your congenital skin type, ethnic origin and your habits determine how quickly and to what extent the described phenomena occur. Dark skin ages more slowly than light skin. You can even say that the darker the skin tone, the slower it ages. To be clear: We are not talking about tanned skin here, but about ethnic differences in people born with dark skin.

Here's a brief look at the effects of sunlight on health and well-being:

We owe our daylight to the fact that every square meter of the sun emits more light than a million light bulbs and that the sunlight which reaches the Earth is scattered by our planet's atmosphere.
Sunlight stimulates our breathing, blood circulation and metabolism
When there is enough sunlight, the body releases more of the happy hormone serotonin, which puts people in a better mood and makes them feel calmer, more satisfied and happier
Sunlight inhibits the creation of the sleep hormone melatonin that makes us feel tired
The sun’s rays stimulate the formation of nitric oxide in the skin, which in turn encourages the expansion of blood vessels, reducing arterial pressure and lowering blood pressure. This reduces the risk of heart attack and stroke over the long term
Sunlight is the most important natural source enabling the body to produce vitamin D.

The sun makes us look old

In addition to the internal, genetically-induced processes of aging (so-called intrinsic skin aging), there are external influences (extrinsic skin aging) that play a role. Factors determined by our lifestyle and climate intensify the process of skin aging.

The main driving factor here is UV radiation from sunlight. Experts refer to this as light-induced aging (photoaging). People who spend a lot of time in the sun or enjoy sunbathing show early signs of aging. It can be assumed that sunlight is responsible for up to 90% of visible skin changes and aging.

Our skin and our eyes are the organs that absorb radiation. UVB radiation that hits the earth accounts for about 5% of total UV radiation. The other 95% is in the longer UVA wave range. What happens when we encounter UV radiation, or rather, when UV radiation hits our unprotected skin? A small portion of the radiation is directly reflected on the surface of the skin. However, much of this radiation literally penetrates the skin.

Skin properties

Youthful skin is characterized by firmness, malleability, elasticity and even pigmentation
Older skin is characterized by dryness, roughness, flaking, itching, wrinkles, irregularities in pigmentation, sagging and thinning

The wavelength makes the difference when it comes to the penetration depth. UVB radiation is mainly found in the epidermis, while UVA rays can penetrate deeper into the skin. This is associated with chemical reactions and biological processes that are fundamental to our lives, but also involve dangers. And they can make us look old many years down the line.

As UV exposure increases – and especially when UVA rays reach the dermis – our antioxidant defenses are impaired and an increasing number of free radicals escape being eliminated by the antioxidant defense system. These free radicals can then cause various types of cell damage, including lipid peroxidation and modification of proteins and DNA. In addition, the influence of UVA can cause the body’s own DNA repair system to lose its capabilities and cause inflammation.

UVA rays can also affect melanocytes in the deeper layer of the epidermis, which can lead to pigment disorders and age spots. This is why it is important that in the future, modern sunscreen products offer a UVA-PF (protection factor) that is higher than the current standard of one third of the SPF. The aim should be to have half or even two thirds of the SPF.

We all get old. However, whether you can really see how old we are also depends on how well we protect ourselves from the sun. Aging well begins at a young age. Remember this the next time you’re out sunbathing. And look forward to your next class reunion with old friends.