Effective sun protection: what you should know

Why effective sun protection is so important

The incidence of skin cancer has risen sharply. In the last two decades, the number of deaths from skin cancer in Germany has risen by around 55% and the number of hospitalised skin cancer patients has even increased by 75% (1).   

The increase in white skin cancer is particularly worrying. Among employees in agriculture, forestry and horticulture, white skin cancer is now at the top of the list of reported occupational diseases, which is why prevention work is so important (2).  

In addition to the risk of skin cancer, intense sunlight also leads to premature skin ageing. Visible signs of this are pigmentation spots and wrinkles caused by the damaging effect of the sun on the skin structure.  

Why is the incidence of skin cancer increasing?  

There are several reasons that could play a role in why the incidence of skin cancer is increasing:  

• Demographic change: people are getting older and spending more time in the sun over the course of their lives. Cumulative UV exposure increases with age, which increases the risk of skin cancer.  
• Vacationing: More people are spending their holidays in sunny regions, even in winter. This increased UV exposure can increase the risk of skin cancer.  
• Improved screening: Advances in medical diagnostics are leading to skin cancer being recognised earlier and more often.  
• Climate change: Experts suspect that climate change has an influence on the increase in skin cancer. Changes in the ozone layer lead to higher UV exposure. A warmer climate also means that people spend more time outdoors, which further increases UV exposure (3).  

Differentiation: UVA and UVB radiation  

Sun protection is particularly concerned with protection against ultraviolet radiation (UV radiation). Like visible light and the infrared range, UV radiation is part of the electromagnetic spectrum of solar radiation. The UV range includes the electromagnetic wavelengths from 100 to 400 nanometres (nm).   

A distinction is made between UVA, UVB and UVC radiation (3):  

UVC radiation: UVC radiation is particularly energy-rich and includes wavelengths below 280 nm. However, this radiation is filtered out by the ozone layer of the earth's atmosphere and does not reach the earth's surface.  

UVB radiation: UVB radiation has a wavelength range of 280 to 315 nm. About 5 % of the UV radiation that reaches the earth is UVB.  

UVA radiation: This includes wavelengths from 315 to 400 nm. UVA radiation accounts for around 95% of the UV radiation that reaches the earth's surface.  

How does UV radiation damage our skin? 

Both UVA and UVB rays can damage our skin. Effective sun protection must therefore be effective against both types of radiation.  

UVB radiation  

UVB radiation is more energetic than UVA radiation, but only penetrates as far as the epidermis due to its shorter wavelength. UVB radiation can cause direct damage to the DNA of skin cells by triggering changes in the DNA structure. If this damage is not repaired, it can lead to the development of skin cancer in the long term.  

In addition to epithelial cells, the epidermis also holds pigment-forming cells known as melanocytes. The melanocytes are stimulated to produce pigment, i.e. melanin, through contact with UVB radiation. The increasing melanin content improves the skin's own protection against UV radiation. The resulting tanning of the skin is therefore a protective mechanism.  

UVA radiation  

UVA radiation penetrates deeper into the skin and can lead to indirect damage by generating free radicals and thus oxidative stress. Free radicals are highly reactive particles that can attack other molecules in the environment. This can lead to damage to proteins, fats or DNA, for example. UVB rays also contribute to the development of oxidative stress in the skin, but to a lesser extent than UVA rays.  

UVA rays play a key role in the skin ageing process. In the dermis, the oxidative stress produced leads, among other things, to damage to the collagen and elastic connective tissue fibres, so that the skin increasingly loses its elasticity and resilience and becomes flabbier and wrinkled. Oxidative stress also promotes hyperpigmentation and thus the development of pigmentation spots.  

DNA can also be attacked by free radicals. UVA rays therefore also increase the risk of skin cancer.  

Sunburn  

Sunburn occurs when the skin is exposed to an excessive dose of UV radiation, especially UVB radiation, within a brief period. This results in burning of the skin, which can be accompanied by redness, pain, swelling and, in severe cases, blistering. Sunburn is therefore severe damage to the skin.   

Sun damage suffered in childhood and adolescence can significantly increase the risk of developing skin cancer later in life. Repeated sunburns and excessive sun exposure at an early age can cause cumulative DNA damage that can later lead to skin cancer.  

Other harmful effects  

In addition to skin damage, UV radiation can also cause other adverse health effects:  

Damage to the eyes: long-term UV exposure can lead to the development of cataracts, which is a clouding of the lens of the eye.  

Immunosuppression: UV radiation can weaken the immune system, reducing the body's defences against infections and diseases. This also increases the risk of skin cancer (3).  

How does skin cancer develop?  

Skin cancer is caused by damage to the DNA in skin cells, which leads to degeneration and uncontrolled proliferation of these cells. In addition to UV radiation, which can come from the sun or from artificial UV sources such as solariums, a genetic predisposition, environmental toxins (e.g. arsenic), ionising radiation (e.g. X-rays) or phototoxic substances that sensitise the skin to UV radiation also play a role in the development of skin cancer.  

Depending on which cell type in the skin is affected, different forms of skin cancer develop:  

Black skin cancer: In black skin cancer (melanoma), the pigment-forming melanocytes are affected. Melanomas are particularly dangerous and can metastasise quickly.  

White skin cancer: This includes basal cell carcinoma and squamous cell carcinoma. White skin cancer is more common but less aggressive than black skin cancer.  

Elements of effective sun protection:

• The most important pillars of effective sun protection are  
• Self-protection of the skin  
• Avoiding strong UV radiation  
• Sun protective clothing  
• Sun cream  

Preventing skin cancer  

In the following, we go into the individual points in more detail and explain what you should pay particular attention to.  

Natural sun protection of the skin  

UV sensitivity can vary greatly from person to person. To better assess UV sensitivity, the skin is categorised into six different skin types. The self-protection time means how long you can stay in the sun without getting sunburnt.  

A distinction is made between the following skin types (4):   

Skin type I: Very light-coloured skin, often with freckles, reddish or reddish-blonde hair, blue or green eyes. Self-protection time: approx. 5 to 10 minutes. Gets sunburnt quickly and hardly ever tans.  

Skin type II: Light skin, blonde to brown hair, blue, green, or grey eyes. Self-protection time: approx. 10 to 20 minutes. Frequently gets sunburnt and tans only moderately.  

Skin type III: Light brown skin, dark blond or brown hair, grey or brown eyes. Self-protection time: approx. 20 to 30 minutes. Tans faster than skin type II and is less likely to get sunburnt.  

Skin type IV: Olive-coloured skin, dark brown hair, brown eyes. Self-protection time: approx. 30 to 40 minutes. Rarely gets sunburnt and tans quickly.  

Skin types V and VI: These skin types include dark-skinned people. A tanning effect is only visible here with extreme sunlight. Sunburn hardly ever occurs. The self-protection time can be over an hour.  

In addition to genetically determined UV sensitivity, there are other factors that influence the skin's resistance. These include acclimatisation to the sun, i.e. whether the skin is already tanned. This extends the self-protection time, but only slightly.  

The supply of micronutrients to the skin is also important. If the skin lacks important vital substances, metabolic processes and repair processes cannot take place correctly. Please also read our article "Beauty from within: Nutrients for skin, hair & nails" and "Natural sun protection from within".  

Avoid intense sunlight  

The intensity of UV radiation varies throughout the day. Around midday, when the sun is at its zenith, UV radiation reaches its maximum intensity. Dermatologists therefore recommend avoiding exposure to the sun between 11 am and 3 pm. During this period, you should therefore preferably stay indoors or in well-protected shady areas.  

What does the UV index mean?  

The UV index is used to compare the intensity of UV radiation. This is internationally recognised and provides information about the current intensity of UV radiation at a particular location.  

The UV index is given on an open-ended scale. The higher the numerical value, the higher the UV radiation intensity and the faster you will suffer sunburn if your skin is unprotected. Protective measures are recommended from a UV index of 3.  

In Germany, values of 8 to 9 are reached in summer, in mountainous areas even up to 11. Values of 12 and higher can occur at the equator. You can find out the current UV index in weather apps or on the websites of weather services. During the day, the UV index is highest between 11 am and 3 pm.  

Reflective surfaces such as sand, water and snow can significantly increase the UV index locally, so you should be particularly careful in such situations, e.g. on a beach or skiing holiday. 

Influence of cloud cover and shade?  

Many people neglect sun protection when it is cloudy or in the shade. However, this is not recommended as the UV intensity can still be high. In the shade, for example, you are still exposed to up to 50 % of UV radiation due to the reflection of ambient radiation. 

Light cloud cover also hardly reduces the UV index. Additional scattered radiation can even lead to an increase in the UV index. Dense cloud cover, on the other hand, can block up to 90 % of UV radiation (5).  

Sun protective clothing  

The best protection against UV radiation is achieved with clothing. Headgear and sunglasses protect the sensitive areas of the scalp and eyes.   

Simple, thinner clothing, such as a long-sleeved T-shirt, corresponds to a protection factor of around 20, while more robust clothing has a correspondingly higher protection factor of 50 or more. In contrast to sun cream, the protection provided by clothing is immediate, uniform and remains unchanged (3).   

For particularly good protection, there is also special UV protective clothing made of tightly woven fabrics. UV protective clothing is an excellent choice in summer, especially for children, who are more sensitive to UV radiation than adults.  

Sun cream  

In addition to the measures mentioned so far, the use of sun cream is also a key part of sun protection for the skin. Below we explain how you can compare the protective effect of various products and what you should bear in mind when applying sun cream. In our article on the ingredients of sun cream, you can also find out which ingredients could be harmful to your health.  

To have a good protective effect, it is important that the sun cream used protects against UVA and UVB radiation. However, people often only pay attention to the sun protection factor. However, this information is not sufficient to assess UV protection.  

What is the sun protection factor?  

The sun protection factor (SPF) indicates how well a sun cream protects the skin from UVB rays. The sun protection factor says nothing about UVA protection. The specified value indicates how much longer you can stay in the sun with the sunscreen product without getting sunburnt compared to unprotected skin.   

For example, a sun protection factor of 30 means that you can theoretically stay in the sun 30 times longer before getting sunburnt. However, it should be noted that the actual protection depends on several factors, such as the intensity of the sun exposure, the skin type and the amount of sun cream applied.  

It is also important to note that the sun protection factor only applies once a day. This means that reapplying sun cream several times will not prolong the protection. For example, if you protect yourself for 10 minutes and apply a product with SPF 20, you can stay in the sun for 200 minutes that day, regardless of whether you apply sun cream again.  

How is protection against UVA rays specified?  

According to EU regulations, UVA protection should be at least one third of UVB protection. This is indicated by the "UVA seal" on the packaging, which consists of a circle containing the letters "UVA".  

Another classification is the PA system (Protection Grade of UVA), which was developed in Japan. The PA system uses a plus sign to show the degree of protection. It ranges from PA+ for basic protection against UVA rays to PA++++ for the highest protection.  

How often should you reapply?  

Sweating, contact with water, dirt or rubbing your face can remove the sun cream. In such cases, you should reapply sun cream several times to maintain the existing protection.  

Is "waterproof sun cream" truly waterproof? 

Creams are considered "waterproof" if they still offer at least 50% of the declared protection after rinsing off. Even waterproof sun creams must therefore be reapplied after bathing to maintain protection.   

How much sun cream should you apply?  

You shouldn't skimp on sun cream. We recommend applying at least 30 ml or 3 to 4 tablespoons of sun cream to the entire body. Only by applying a sufficient amount of product is the specified protection guaranteed.  

Early detection of skin cancer  

In Germany, it is recommended that skin cancer screening is carried out every two years from the age of 35. This screening is covered by statutory health insurance and includes a thorough examination of the entire skin by a dermatologist. Screening can also be useful at a younger age. However, this is not covered by all health insurance companies.  

People with a higher risk of skin cancer, for example due to a family history, frequent sun exposure or many moles, should be examined more frequently and should discuss this individually with their doctor.  

Do you need UV protection indoors?  

In general, UV protection is much less necessary indoors than outdoors, as window glass blocks most UVB radiation. However, UVA rays can penetrate through ordinary window glass and affect the skin. 

In certain situations, it may therefore make sense to take UV protection measures indoors as well. These situations include, for example, long car journeys or spending extended periods of time near large windows, especially in direct sunlight. It also makes sense to apply sun protection if you work in an office flooded with light.  

Conclusion - Effective sun protection has many sides  

Protecting the skin from UV radiation is important and should not be taken lightly, as sun damage can add up and often only becomes clear many years later. Effective sun protection goes far beyond simply applying sun cream and includes measures such as avoiding intense sunlight, wearing protective clothing and regular skin cancer screening.  

Sources:

• Number of inpatient skin cancer treatments has risen by 75 % within 20 years. Federal Statistical Office [Internet]. [accessed on: 28/06/2024].
• Doubling of skin cancer cases expected by 2030. Leipzig University Hospital [Internet]. [accessed on: 28/06/2024].
• Health guideline: Prevention of skin cancer. Oncology guideline programme [Internet]. Status February 2022 [accessed on: 28/06/2024].
• The different skin types. Federal Office for Radiation Protection [Internet]. [accessed on: 28/06/2024].
• Factors of UV exposure. Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology [Internet]. [accessed on: 28.06.2024].