Australian study: there is no 'safe' sun exposure without sunscreen

A new study by Australian researchers challenges a widely held belief that sun exposure early in the morning or late in the evening does not cause skin damage. The findings come from a team at the QIMR Berghofer Medical Research Institute in Australia and were published in the scientific journal Photochemistry and Photobiology, according to a press release cited by the Xinhua news agency and reported by Agerpres.

According to the researchers, what matters for skin health is not the duration of sun exposure, but the total dose of ultraviolet (UV) radiation received. As such, a person can accumulate the same amount of UV radiation over a short period at midday as they can over a longer period in the early morning or late evening.

"You can receive the same dose of UV radiation over a short period of time in the middle of the day, or over a longer period early in the morning or late in the evening. Our research has shown that it is the total dose that matters, not how long it takes to receive it," explained Rachel Neale, Professor at QIMR Berghofer and one of the study's lead researchers.

She also drew attention to a real risk: when the intensity of sunlight appears low, people tend to spend more time outdoors without adequate protection, with a false sense of security. "We have demonstrated that this poses a problem in terms of skin damage," Neale noted.

The researchers analysed skin biopsies and identified DNA damage, as well as cellular stress responses, regardless of whether UV exposure occurred rapidly or gradually. Among the biomarkers measured was the p53 protein, associated with DNA damage, and the results showed harmful effects even at radiation levels below those that cause visible skin reddening.

David Whiteman, Professor at QIMR Berghofer and lead researcher on the study, emphasised that repeated exposure, even at low levels of solar radiation, can "have a cumulative impact on the skin and lead to mutations that will trigger skin cancer".

The research team noted, however, that sunlight remains important for vitamin D production and overall health. Their recommendation is that sun protection should be used more consistently, including during brief exposures or when the intensity of sunlight appears low.