Temperatures in Canberra are finally starting to hit the low 20s, which is, of course, pool party weather. For those of us not blessed with the ability to tan, sunscreen is becoming a hot topic. Oddly enough, the next big advance in sun-shielding technology might be thanks to sweaty hippos.
Everyone knows that too much sun is bad for you, and there’s growing evidence suggesting that too little sun can be just as dangerous. The kinds of ultraviolet (UV) radiation that affect us the most are separated into two different ranges of frequencies: UVA and UVB. UVB affects the outer layers of our skin. It is responsible for sunburn and the occurrence of most skin cancers. UVA, on the other hand, penetrates further and affects the deeper layers of skin. UVA causes both wrinkles and loss of skin elasticity, and some skin cancers have been associated with this range of radiation too. UVA also causes tanning, which is the body’s response to DNA damage.
Neither kind of radiation is ideal for prolonged, unprotected exposure, but hiding indoors for fear of melanoma is neither fun nor sensible. Vitamin D is produced in our skin when we are exposed to UVB radiation. Lack of exposure to sunlight can result in vitamin D deficiency, which is associated with reduced immune system effectiveness, bouts of flu, tiredness, and muscle weakness. Vitamin D deficiency has also been linked to asthma, heart disease and cancer.
Here in Canberra, the ideal amount of unprotected sun exposure varies from a few minutes a day in summer to several hours a week in winter. People with fairer skin may need even less than these recommended times, while people with darker skin may need more sunlight to reach healthy vitamin D levels.
After you’ve met your vitamin D requirements, it’s probably a good idea to lather on some sunscreen. Modern sunscreens are fantastic concoctions that typically combine chemical ‘screens’ and physical ‘blocks’ for UV radiation. Chemical components absorb UV before it reaches your skin, while physical ingredients reflect UV away. The higher the listed sun protection factor (SPF), the longer you can be exposed to sun before damage to your skin will occur. SPF 15 will protect you for fifteen times longer than your natural defences, SPF 30 for thirty times longer, and so on.
Unlike humans, who have to cover ourselves with sunscreens, hippos have the amazing ability to sweat out their own sunscreen. Hippos secrete a bizarre red substance that resembles blood, but actually absorbs and reflects harmful UV very effectively. This hippo sweat is also an insect repellent and an antiseptic. It’s basically a sticky crimson wonder-substance. Investigations into how to harness this hippo-power are underway. You might be buying hippo-inspired sunscreens in the near future, and given sunscreens are known to be the best anti-ageing creams available, your skin will thank you for it.