解暑知識小科普 這個夏天讓你“透心涼、心飛揚”

6月中旬以來，我國北方地區出現持續大范圍高溫天氣。北京、天津、河北、內蒙古東南部、遼寧大部、山東北部等地出現35℃以上的高溫天氣，其中北京北部、河北東部、遼寧西部局地氣溫突破40℃。多日的高溫洗禮使得北方提前開啟“燒烤”模式，這讓不少北方民眾感到不太適應。

有網友曬出南北方氣溫對比的圖片，稱作為東北人，從來沒受過這么大“委屈”。還有網友戲稱，看來重慶、武漢、南昌、長沙“四大火爐”的稱號是要易主了。

面對步步逼近的高溫天氣，應該如何保持清涼舒爽呢？是泡在冰水里？

還是一頭鉆進冰箱？

或者干脆抱著冰塊消暑？

其實除了空調、電扇、涼水、冰飲料，還有很多科學的防暑小知識，學會這些保證你整個夏天“透心涼、心飛揚”。

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

A white cotton top and shorts is obviously the best thing to wear, right? Sort of.
白色棉質上衣搭配短褲顯然是最佳著裝，對嗎？在某種程度上是的。

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.
亞麻、棉布等天然布料吸汗且透氣。比聚酯纖維等人造纖維要好得多，聚酯纖維會困住皮膚上的水分，讓你感到悶熱不適。

But when it comes to colour, things get a little more complicated.
但說到顏色，情況更復雜一些。

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.
如果直接在太陽下暴曬，那么白色是沒錯的。相比其他顏色，白色能更好反射熱光。但是如果你身處陰涼處，那么黑色的效果會更好，因為它能把熱量釋放到環境中，為你降溫。

Drinking hot drinks actually lowers your body temperature
喝熱飲實際上會降低體溫

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.
保持水分非常關鍵。據英國國家醫療服務體系稱，如果不攝入大量的水分或果汁等飲品，人們就會出現頭痛、疲勞等不適癥狀。這可能導致熱衰竭和中暑，最嚴重時可能危及生命。

But what about hot drinks? Can they help cool you down? Well, it comes back to sweat again.
那么熱飲怎么樣呢？它能讓你涼快起來嗎？好吧，又要從流汗說起了。

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.
原理就是喝熱飲會讓人體溫升高，開始流汗。出汗能讓你涼快，因為汗水蒸發會帶走身體的部分熱量。

But sweating also means that you are losing liquid from your body, meaning you need to take on more to stay hydrated.
但出汗也意味著體內水分正在流失，所以你需要喝更多水補充水分。

Keep the curtains closed - block out the sun
拉上窗簾，遮擋太陽

This is another one where there is no precise answer.
這是另一個沒有標準答案的問題。

If you have thick dark curtains then keep them open, otherwise the fabric can keep the heat trapped in the room.
如果你家窗簾是深黑色的，那就把它拉開，否則窗簾會將熱量關在房間里。

Lighter curtains can help reflect the sun's rays back out of the room, so keep them closed.
顏色較淺的窗簾有助于將太陽光反射出房間，所以請把它拉上。

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東西可以反射熱量，讓房間保持涼爽。

I never shut the windows during summer - you need to circulate the air
我夏天從不關窗戶，因為空氣需要流通

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，這個問題也沒有硬性規定。當你開窗或開門時，應該要時刻考慮家里的安全性。

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.
如果房間的溫度比外面的溫度低，那么就關上窗戶，否則你只會把熱空氣放進來。

But if the room is warmer then opening the windows will help cool your home down.
但如果房間里更熱，那么打開窗會讓你家更涼快些。

英文來源：BBC
翻譯&編輯：董靜
審校：yaning