如何在夏天保持凉爽

Summer is coming. When those days come, every second you spend outside feels like a dehydrating walk through the sauna. But don’t sweat. There are ways to cool your body down without resorting to a portable AC unit.
酷夏即将来临。当最热的时候到来时，在室外的每一秒都像是桑拿屋里的脱水之旅。但是别紧张，总有让你不用便携空调也能保持身体凉爽的方法。

Scientists first started studying how weather contributes to human comfort in the 1960s. That’s around the time when the invention of air conditioning finally let us control the temperatures of office buildings and homes. A scientist named Povl Ole Fanger came up with an equation called the comfort equation, which took into account a variety of different variables, including temperature, humidity, air velocity, clothing resistance, and activity level. His equation has also helped us better understand how the human body cools itself—and how to stay chill even on the hottest of days.
科学家第一次研究天气对人体舒适度的影响是在20世纪60年代。差不多在同时期，空调的发明让我们可以随意调节办公楼和家里的温度。一位名叫伯维尔·欧乐·范格的科学家提出了一个舒适度方程，方程要考虑的变量包括温度、湿度、气流速度、穿着和活动量。他的这个方程帮我们更好地了解人体自我降温的原理，以及如何在最热的天气里保持凉爽的。

Wear loose clothing, mostly cotton
穿棉质宽松的衣服

This seems obvious, but wearing clothing that is loose rather than tight allows air to flow past the skin. This carries away the warmth that your body generates and allows cooler air to flow back in. Clothes like tight jeans or a snug jacket trap that heat against your skin, which just makes you feel hotter. On the other hand, less fitted clothes like loose pants, a flowy shirt, or a dress all allow air to keep circulating.
这一条似乎显而易见，比起穿紧身的衣服，宽松的衣服可以使空气在皮肤上流动。这样（宽松的衣服）可以带走你身体产生的热量，也可以让凉爽的空气流入进来。紧身牛仔裤和紧身夹克之类的衣服会把热气禁锢在你皮肤上，会让你觉得更热。另外，像是宽松的裤子、飘逸的衬衫或裙子等等不那么紧身的衣物可以保持空气的流通。

The type of fabric you wear has an influence, too. When it’s really hot out, materials that “breathe”—allowing the flow of air through the fabric itself—also work to keep you cool. Cotton and linen are among the most breathable fabrics, so look for clothes made of those substances, as opposed to less permeable synthetics.
衣物的面料也是有影响的。室外十分炎热的时候，可以“呼吸”的面料也能让你感到更凉爽，因为空气可以穿过面料本身。棉和亚麻是最透气的面料，所以多穿这些面料的衣物，少穿透气性差的人造纤维面料。

Apply cold packs strategically
巧用冷敷袋

Your body regulates its temperature via a small peanut-shaped section of the brain known as the hypothalamus. This region works almost like a thermostat in a home, turning the temperature up or down based on various factors—such as how cold or hot the skin is.
人的身体通过脑部花生大小的下丘脑来调节体温。下丘脑的工作原理和家中的恒温器相似，根据不同的因素来调高或降低体温，比如说，根据皮肤温度的冷热。

Certain parts of the skin have a larger influence than others. These areas are called pulse points. They get their name because you can feel your pulse there, and the reason you can do that is because vessels are so close to the edge of your skin that one can easily hear or feel the flow of blood.
有些特定部位的皮肤对下丘脑的影响比其他部位更显著，这些位置就是脉搏点。之所以叫脉搏点是因为在这些地方可以感受到脉搏，而且因为这里的血管和皮肤最近，人们可以轻易地听到或感触到血液的流动。

When you want to lower your body temperature, chilling those pulse points with cold water or ice sends a signal to the brain that says, “I’m cold.” This tricks your brain into turning down its thermostat. Focus on pulse points that are easy to reach: the insides of your wrists, the area around your temple, and your neck. Holding an ice pack or even a cold washcloth against the skin on these regions will make your entire body feel cooler.
想降低体温时，用冷水或者冰块冷敷这些脉搏点会向大脑传递一个信号——“我好冷”。这样做可以欺骗大脑让它降低身体“恒温器”的温度。你可以从几个方便的脉搏点着手：手腕的内侧、太阳穴附近的区域还有颈部的区域。用一个冷敷袋或是一块凉毛巾放在这些地方的皮肤上会让你整个人都感觉凉快一些。

Count your steps
少运动

Exercising in extreme heat is usually not recommended. That’s because exercise actually heats the body up further and causes you to sweat, both of which make you feel more uncomfortable. When you’re sweating more, you’re also at greater risk of dehydration. So when it’s terribly hot outside, make sure you don’t exercise too much.
通常不推荐在酷热的天气里锻炼。因为运动会使人体体温进一步升高并且会导致出汗，这两样都不会让人感觉太舒服。人大量出汗时，还会增加脱水的风险。所以在室外特别炎热的时候，确保不要运动得太厉害。

Hydrate
补充水分

Speaking of sweat, that’s the best method our bodies have evolved to regulate body temperatures. Sweating helps to cool off the skin, which keeps the rest of us cool. And the human body can regulate itself far more easily when it’s fully hydrated.
谈到出汗，这是我们身体调节体温的最佳方式。出汗可以使皮肤温度下降，这样也会让我们觉得很凉爽。而且当人体水分充足时，也是调节体温最容易的时候。

Proper hydration regulates blood flow, which, in turn, helps to determine the temperature of the skin. That then tells our master thermostat, the hypothalamus, how to regulate our internal temperature.
适当的水分可以调节血流，反过来也能决定皮肤的温度。而且这还能告知作为“恒温器”的下丘脑如何来调节人体的内部温度。

The sad part is that, by the time you feel thirsty, you are already dehydrated. So, to prevent dehydration and its negative effects, you should be drinking water throughout the day on a regular basis—even before you feel thirst.
悲剧的是，等你感觉到口渴的时候，你已经脱水了。所以，为了避免脱水和它带来的负面影响，我们应该在一天中定时补充水分，而且要在感觉到口渴之前就喝水。