In winter UV exposure goes down to the poles, but does that mean we should use less SPF?
Jon Bower/Alay
This article is part of a special issue investigating key questions about skin care. Find the complete series here.
Even if we live far from the equator, we are often told to apply sun protection factor (SPF) lotions all year round to protect our skin from premature aging and wrinkles. But does solid science back this up?
Simply put 13.5 percent US adults use SPF creams as part of their daily routine, according to a survey. This is clearly a problem in the summer, when the sun is at its brightest. Even if we don’t show any signs of burning, UV rays can penetrate and damage the deeper layers of the skin. In addition to contributing to wrinkles, this can lead to skin cancer, and people who use sunscreen are at a much lower risk.
Photoaging is a cumulative effect that builds up over decades
However, these rays are much weaker in winter at northern or southern latitudes, and the benefits of SPF must be balanced against the costs. Brian DiffeyThe emeritus professor of photobiology at Newcastle University in the UK has stated Using SPF in winter can help with vitamin D deficiencyfor example SPFs can also have an environmental cost, as research shows they can end up in the oceans, where their chemical components can be absorbed by corals and other marine life, harming them.
Diffey used historical climate records how to calculate…
