I don't mean to sound like a Monty Python sketch, but when I was a student and the pipes froze, if we wanted a cup of coffee we had to melt some snow first. That was not the most amazing thing, though. The most amazing thing, I now realise, was that for the whole of an unusually harsh winter, spent in a house later condemned as unfit for human habitation, I did not wear a vest. I did not even own a vest. I dealt with the extreme cold by piling on jumpers and jackets and coats, usually from the menswear rail in charity shops.
A quarter of a century later, I have a whole drawer full of vests. Most are cotton, but some are silk; some have spaghetti straps, others lead a double life as T-shirts in the summer. Their proliferation is partly because clothes have changed. The whole underwear-as-outerwear thing has left its legacy, and women’s tops are often sheer, lacy or cut so low that you need something beneath to preserve a bit of modesty. But mostly they are for warmth: I even have a cashmere vest, which goes under my party clothes when I suspect an evening of glacial air-conditioning lies ahead.
In Britain, "vest" means underwear, but in America it is a kind of outerwear: it can be the waistcoat of a three-piece suit, a sleeveless pullover, or a protective layer which might be bullet-proof or high visibility. What the British call a vest, Americans know as a tank top or—charmingly, if worn on its own by a man—a wife-beater. What is fundamental, though, on both sides of the Atlantic, is that a vest has no sleeves: it covers your core.
Not so long ago the word "core" was only ever attached to "apple" or "Earth's". Today, it’s a part of our anatomy. Fitness instructors go on about strengthening your core, to guard against back injury, to get a flat stomach, or to help your posture. A whole generation of young men is obsessed with core workouts, and you can barely leave home without seeing a naked core, usually David Beckham's. And just as the core is the key to fitness, in both the ancient and modern senses of that word, so too is it the key to keeping warm. If your core—formerly known as your torso—is warm enough, it will send blood to your extremities, which will in turn feel warm. But if your core is cold, your hands, feet and nose don’t get a look-in: the body's priority is to keep the engine-room going.
Humans are basically tropical creatures who survive in colder climates because of evolutionary adaptations and clothing; without clothes we wouldn’t have made it far out of Africa. Without clothes, modern polar explorers would quickly die of hypothermia—in a world obsessed with breaking records, no one has attempted to be First Naked Person to either of the poles. It is sobering to think of the kit that was available to Robert Scott and his team in the Antarctic just over a century ago. They wore woollen underwear, and reindeer-skin boots lined with felt and insulated with a kind of hay. An outer canvas jacket did for wind-proofing, while the layers they wore between undies and jacket trapped and insulated the air warmed by their bodies.
This is what is known as "loft". It’s not just a space full of junk at the top of a house, but the thickness of the insulation you might put in there, or of a duvet, or of those full-length padded coats that look like sleeping bags and are only slightly easier to walk in. Loft is the key when it comes to keeping warm—ask any serious climber or mountaineer. Like Scott, they up their loft by dressing in layers—but of high-tech fabrics that are lightweight, hydrophobic, able to “wick away” the moisture from our skin, and probably light the Primus stove too.
People who spend their youth in a cold climate might not need so much loft, as they develop modifications to their circulatory systems. Evidently the house I grew up in was too warm for that, even though it wasn’t unknown to find snow on the windowsill inside my parents’ bedroom. I remain stubbornly unevolved in the circulation department, so I rely on clothes to do the work. In January and February I am never far away from—and usually inside—a down-filled gilet from Uniqlo, which weighs about the same as my mobile phone and squashes down to the size of a fist. The shop calls it an Ultra Light Down Vest, but it's the American kind of vest, worn on top of your clothes. Of course I wear the English kind too, underneath. Winter is a two-vest problem.