Running in Cold Weather Improves Performance
From VOA Learning English, this is the Health & Lifestyle report.
Today's program is for people who like to run.
Cold weather during winter months may keep many people from leaving home and running in the open air.
However, a new study shows that the drop in temperature is a good reason to run. In fact, researchers say, running in cold weather helps improve one's performance.
Many people say running in the winter can be difficult. Two reasons are the low temperatures and bitter winds. Yet many runners might find it easier than running in hot weather.
That could be because lower temperatures reduce stress on the body. When you run in cold weather, your heart rate and the body's dehydration levels are lower than in warmer conditions. The body needs less water on a cold day than in warm weather.
This information comes from sports scientists at St. Mary's University in London. John Brewer is a professor of applied sport science at St. Mary's.
For this study, he and other researchers put a group of people into a room they called an "environmental chamber." The researchers then recreated summer and winter weather conditions in the room. The test subjects were asked to run 10,000 meters under both conditions. Brewer says he and his team recorded biological measurements of the runners.
"We've got a group of subjects into the environmental chamber, we've changed the conditions to replicate the summer or winter and we've got them to run a 10k under both of those conditions and taken various measurements on each runner whilst they've been completing their 10k."
Brewer says every movement runners make produces heat. He explains that one way in which we lose heat is by sweating. The body loses heat through droplets of sweat. He says the body also loses heat by transporting the blood to the surface of the skin.
"That heat builds up in the body and can be really damaging unless you can lose that heat. One of the mechanisms by which we lose heat is through sweating, but we also lose heat by transporting the blood to the surface of the skin where it can lose heat out into the external environment. Now, that puts more strain on the heart, particularly in hot conditions because it's much harder to lose heat when the external environment is warm as well."
And that increased strain, adds Brewer, can be considerable. Running in higher temperatures results in faster heart rates.
"We found, for example, that heart rates were about 6 percent higher in the hotter conditions. We found that the runners dehydrated by around 30, 38 percent more in those hotter conditions. And they found it about 30 percent easier -- the test of their thermal regulation, how they felt, (and) their perception of heat -- was around a third lower when they were running in cold conditions."
The body does not have to work as hard to pump blood to the skin's surface. Brewer says that means running in cooler temperatures requires less energy. He adds that serious runners could cut valuable seconds off their personal best times by choosing to run in the winter.
"If you look at top-level sports, if you look at the likes of Mo Farah running 10Ks and winning world and Olympic championships; the difference between success and failure is seconds, and it's certainly not minutes. We can be very confident that in cooler conditions you can certainly slice a decent percentage of time off your personal best."
Several websites note that the most important thing for people who run in cold conditions is to wear the right clothing. Keeping as dry as possible is most important when exercising in low temperatures. Wear mittens on your hands instead of gloves. Wear shoes that will keep you from falling. And especially, wear more than one layer of clothing to keep sweat away from your skin.
So, if you are a runner, don't let winter weather keep you indoors. Simply get ready for the low temperatures and start running.
I'm Anna Matteo.
1.the open air 露天
We sleep out under the stars, and eat our meals in the open air.
2.as well as 也；和...一样
It is in his best interests as well as yours.
3.a group of 一组；一群
Suddenly the door opened and a group of children burst in.
4.work hard 努力学习
How do you motivate people to work hard and efficiently?
1.And especially, wear more than one layer of clothing to keep sweat away from your skin.
keep away from 使...远离
Keep away from the doors while the train is moving
If you don't keep away from the dog, you may be bitten.
2.Simply get ready for the low temperatures and start running.
get ready for 准备
I suggest you get ready for my hammer!
I have a lot of work to do to get ready for tomorrow.
然而，一项新研究表明，气温下降是跑步的绝佳时机 。研究人员表示，在寒冷的天气中跑步有利于改善身体机能 。
很多人认为冬季跑步阻碍太多 。低温和凛冽寒风是两大阻碍因素 。然而，还有许多跑步者发现严冬时节跑步比炎夏季节更容易 。
这是因为低温环境能够降低身体的压力 。与温暖的环境相比，在寒冷的环境下跑步，你的心率和身体的脱水程度更低 。寒冷的环境下，身体需要的水分较少 。
以上结论由伦敦圣玛丽大学的运动科学家得出 。约翰·布鲁尔（John Brewer）是圣玛丽大学的应用运动科学教授 。
为了进行研究，他和其他工作人员让受试者进入名为“环境室”的房间 。然后研究人员在房间里模拟夏天和冬天的环境 。他们要求受试者在两种环境下跑完10,000米 。布鲁尔表示，他们记录下受试者的各项身体指标 。
布鲁尔还表示，受试者的每一步都会产生热量 。他进一步解释称，流汗是人体散发热量的途径之一 。身体通过汗液进行散热 。身体还会通过将血液输送到皮肤表面进行散热 。
“这种热量会逐渐在体内累积，除非散发出热量，否则可能会受到伤害 。散发热量的途径之一就是出汗，不过也可以通过将血液输送到皮肤表层，皮肤表层可将热量散发到外部环境 。此时，心脏会受到更大的压力，尤其是在炎热环境下，因为外部环境温度较高时，热量难以散发出来 。
布鲁尔补充道，这种不断增加的压力强度非常大 。温度越高，心率会越加频繁 。
“例如，我们发现在较热的环境下，心率比平时高出约6％ 。在气温较高的环境下，跑步者脱水程度约30.38％，而且他们发现，在温度较高的环境下，人体热调节测试比寒冷环境容易30％，而在寒冷环境下对热的感知比高温环境低约三分之一 。
人体无需特意将血液输送到皮肤表层 。布鲁尔表示，也就是指在低温环境下，跑步需要更少的能量 。他还指出，热衷于跑步的人可选择在冬天跑步，那就可以在个人最佳时间内节省关键的几秒钟 。
“如果你观察下高水平的竞技运动，看看莫·法拉（Mo Farah）的长跑10 公里赢得世界和奥运的冠军，成败之别在于秒，当然不是分钟 。我们非常有信心，在寒冷的环境下，你当然可以节省时间，取得个人最佳时间 。
数个网站指出，对于在寒冷环境下跑步的人来说，最重要的是穿着保暖 。在低温下锻炼时，应尽可能保持干燥 。佩戴露指手套而不是密闭手套 。穿上防滑鞋子以免摔倒 。还有一点需要注意，不要只穿一层衣服，因为要保持汗液远离皮肤表层 。
所以，如果你爱好跑步，请不要逃避室外的严寒 。只要做好保暖工作就可以开跑了 。