解暑知识小科普 这个夏天让你“透心凉、心飞扬”

6月中旬以来，我国北方地区出现持续大范围高温天气。北京、天津、河北、内蒙古东南部、辽宁大部、山东北部等地出现35℃以上的高温天气，其中北京北部、河北东部、辽宁西部局地气温突破40℃。多日的高温洗礼使得北方提前开启“烧烤”模式，这让不少北方民众感到不太适应。

有网友晒出南北方气温对比的图片，称作为东北人，从来没受过这么大“委屈”。还有网友戏称，看来重庆、武汉、南昌、长沙“四大火炉”的称号是要易主了。

面对步步逼近的高温天气，应该如何保持清凉舒爽呢？是泡在冰水里？

还是一头钻进冰箱？

或者干脆抱着冰块消暑？

其实除了空调、电扇、凉水、冰饮料，还有很多科学的防暑小知识，学会这些保证你整个夏天“透心凉、心飞扬”。

Cotton is the only fabric that keeps me cool
棉布是唯一可以保持凉爽的布料

A white cotton top and shorts is obviously the best thing to wear, right? Sort of.
白色棉质上衣搭配短裤显然是最佳着装，对吗？在某种程度上是的。

Natural fabrics like linen and cotton absorb sweat and allow it to breathe. They're much better than man-made fibres like polyester, which can trap the moisture against your skin, leaving you hot and uncomfortable.
亚麻、棉布等天然布料吸汗且透气。比聚酯纤维等人造纤维要好得多，聚酯纤维会困住皮肤上的水分，让你感到闷热不适。

But when it comes to colour, things get a little more complicated.
但说到颜色，情况更复杂一些。

White is good if you're out in direct sunlight a lot - it will reflect the heat better than any other colour. But if you're spending time in the shade, black is a more effective colour to wear as it radiates out heat into your environment, cooling you down.
如果直接在太阳下暴晒，那么白色是没错的。相比其他颜色，白色能更好反射热光。但是如果你身处阴凉处，那么黑色的效果会更好，因为它能把热量释放到环境中，为你降温。

Drinking hot drinks actually lowers your body temperature
喝热饮实际上会降低体温

Staying hydrated is key. According to the NHS, if you don't drink lots of water and beverages like fruit juice, you can start to become unwell, with symptoms of headache and tiredness. It can lead to heat exhaustion and heatstroke, which in the worst cases can be fatal.
保持水分非常关键。据英国国家医疗服务体系称，如果不摄入大量的水分或果汁等饮品，人们就会出现头痛、疲劳等不适症状。这可能导致热衰竭和中暑，最严重时可能危及生命。

But what about hot drinks? Can they help cool you down? Well, it comes back to sweat again.
那么热饮怎么样呢？它能让你凉快起来吗？好吧，又要从流汗说起了。

The thinking is, drinking a hot drink raises your body temperature, causing you to sweat. Sweating cools you down because as the moisture evaporates it takes away some of the heat of your body.
原理就是喝热饮会让人体温升高，开始流汗。出汗能让你凉快，因为汗水蒸发会带走身体的部分热量。

But sweating also means that you are losing liquid from your body, meaning you need to take on more to stay hydrated.
但出汗也意味着体内水分正在流失，所以你需要喝更多水补充水分。

Keep the curtains closed - block out the sun
拉上窗帘，遮挡太阳

This is another one where there is no precise answer.
这是另一个没有标准答案的问题。

If you have thick dark curtains then keep them open, otherwise the fabric can keep the heat trapped in the room.
如果你家窗帘是深黑色的，那就把它拉开，否则窗帘会将热量关在房间里。

Lighter curtains can help reflect the sun's rays back out of the room, so keep them closed.
颜色较浅的窗帘有助于将太阳光反射出房间，所以请把它拉上。

Putting something reflective on the outside of the glass can bounce the heat away, keeping the room cool.
在窗玻璃外面放一些反光的东西可以反射热量，让房间保持凉爽。

I never shut the windows during summer - you need to circulate the air
我夏天从不关窗户，因为空气需要流通

Sorry - this is another one where there is no hard and fast rule. And you should always consider home security and safety when it comes to leaving windows and doors open.
抱歉，这个问题也没有硬性规定。当你开窗或开门时，应该要时刻考虑家里的安全性。

If the room you are in is actually cooler than the temperature outside then keep the windows closed, otherwise all you are doing is letting hot air in.
如果房间的温度比外面的温度低，那么就关上窗户，否则你只会把热空气放进来。

But if the room is warmer then opening the windows will help cool your home down.
但如果房间里更热，那么打开窗会让你家更凉快些。

英文来源：BBC
翻译&编辑：董静
审校：yaning