Ultraviolet (UV) radiation, a natural part of sunlight, plays a complex role in human health. While it is often associated with negative effects like skin cancer, scientific evidence shows that UV exposure can also offer important health benefits. Two recent studies published in *Photochemical & Photobiological Sciences* shed light on both the positive and negative health impacts of UV radiation, especially in regions like Australia and New Zealand.

1.The Bright Side of UV: Health Benefits

The review by Riedmann et al. (2025) provides an in-depth examination of how UV radiation, especially UVB, can have beneficial effects when exposure is balanced and controlled. One of the most well-known advantages is the stimulation of vitamin D synthesis in the skin. Vitamin D is crucial for bone health, immune function, and potentially for protection against certain diseases, including some cancers and autoimmune conditions.
Besides vitamin D production, UV radiation might also play a role in regulating blood pressure and mood. According to the review, UV exposure can lead to the release of nitric oxide from the skin, which may help reduce blood pressure and support cardiovascular health. There’s also some evidence that sunlight exposure can help alleviate symptoms of seasonal affective disorder (SAD), a form of depression linked to lack of sunlight during certain seasons.
The authors stress that the key lies in moderate exposure. For most people, short daily periods of sun exposure—without sunscreen but outside of peak hours—can help maintain sufficient vitamin D levels without significantly increasing the risk of skin damage.

2. The Darker Side: Risks of Overexposure

Despite the benefits, the risks of too much UV radiation remain a major public health concern. Excessive UV exposure is the leading cause of skin cancers, including melanoma and non-melanoma types. It also contributes to premature skin aging and can cause eye damage such as cataracts.
The authors highlight the need for public awareness strategies to promote safe sun behavior. They recommend using protective clothing, hats, sunglasses, and sunscreen—especially during midday hours and in regions with strong UV radiation.

3. Economic and Health Burden: Insights from the SUNEX Model

To quantify the broader impact of UV exposure, the second paper by Collins et al. (2025) introduces the SUNEX simulation model. This tool estimates the health and economic outcomes related to both over- and under-exposure to solar UV radiation in Australia and New Zealand.
The study reveals a nuanced picture. On one hand, excessive UV exposure leads to a significant number of skin cancer cases, resulting in high treatment costs and lost productivity. On the other hand, insufficient sun exposure also imposes health costs—mostly related to vitamin D deficiency and associated diseases like osteoporosis, cardiovascular disease, and some forms of cancer.
One striking finding is that underexposure may be causing a hidden burden on public health. The authors estimate that a balanced UV exposure strategy could prevent thousands of cases of disease and save millions of dollars annually in healthcare costs across both countries.

4. A Call for Balance

Both studies emphasize the need to find a “Goldilocks zone” for UV exposure—not too little and not too much. This means tailoring sun safety guidelines based on individual risk factors (like skin type and age), environmental conditions (such as season and latitude), and public health priorities.
Educating the public about safe sun practices is critical. For example, brief daily exposure to sunlight on the arms and face might be enough for vitamin D synthesis, especially during summer. At the same time, high-risk groups should be especially cautious during peak UV hours.

5. Implications for Public Health Policy

These findings have important implications for health policy. Governments and health organizations should promote nuanced sun safety messages that do not encourage complete sun avoidance. Public campaigns must balance the risks of skin cancer with the growing awareness of the health problems associated with low UV exposure.
Incorporating UV exposure guidelines into national health recommendations—just like guidelines for diet and physical activity—can help individuals make informed choices about their sun behavior.

Conclusion

UV radiation is neither purely harmful nor purely beneficial—it depends on how much we get and how we manage it. As the studies by Riedmann et al. and Collins et al. show, moderate, sensible sun exposure can support our health, while extreme behaviors at either end—too much or too little—can lead to significant health and economic costs. Public health strategies should aim for a balanced approach, helping people enjoy the sun safely and responsibly.

References:

Riedmann, U., Dibben, C., de Gruijl, F.R. et al. Beneficial health effects of ultraviolet radiation: expert review and conference report. Photochem Photobiol Sci 24, 867–893 (2025). https://doi.org/10.1007/s43630-025-00743-6  

Collins, L.G., Elliott, T.M., Webb, A. et al. Estimated health and economic effects associated with over- and under-exposure to solar ultraviolet radiation in Australia and New Zealand using the SUNEX simulation model. Photochem Photobiol Sci 24, 895–908 (2025). https://doi.org/10.1007/s43630-025-00726-7