Frostbite is one of the most common.

　　冻伤就是最常见的危险之一。

　　Edward Ward is a doctor at Rush University Medical Center. He explains how frostbite happens.

　　爱德华.沃德是拉什大学医学中心的医生。他解释了冻伤是如何发生的。

　　"When the air temperature drops below zero especially factoring wind chill, things freeze. And that includes the fluids that’s within your fingers or your toes, nose, ears, anything that’s exposed to that wind chill can be affected by frostbite."

　　他说：“当气温下降到零度以下，尤其是加上风寒，万物就会冻住，其中就包括人们的手指、脚趾、鼻子、耳朵里的液体。任何暴露在风寒中的物体都可能会受到冻伤影响。”

　　Protecting your fingers, toes, ears and nose is very important. Cold winds affect these parts of the body more quickly than other parts.

　　保护你的手指、脚趾、耳朵和鼻子是非常重要的。寒风对人体这些部位的影响比其它部位更快。

　　Christopher Sampson is a doctor with University of Missouri Health Care. He explains that frostbite can happen rapidly -- in less than 30 minutes.

　　克里斯托弗.桑普森是密苏里州大学卫生保健部门的一位医生。他解释说，冻伤可能会在30分钟内迅速发生。

　　"With frostbite people can start experiencing symptoms pretty rapidly, on average with mild winds and cold temperatures it can occur in as less than 30 minutes, with extreme cases. When it’s very, very cold and winds are very, very strong, sometimes frostbite can develop in as little as 5 minutes."

　　他说：“人们冻伤后很快会开始出现症状。一般在微风和寒冷气温下，它会在不到30分钟内发生。在极端情况下，当天气很冷风很大时，有时候短短五分钟内就会冻伤。”

　　The beginning of frostbite is called "frostnip."

　　冻伤的初步症状被称之为“亚冻伤。”

　　Experts at the Mayo Clinic explain that "with this mild form of frostbite, your skin pales or turns red and feels very cold. Continued exposure leads to prickling and numbness in the affected area. As your skin warms, you may feel pain and tingling. Frostnip doesn’t permanently damage the skin."

　　梅奥诊所的专家解释说，“这种轻微冻伤会使你的皮肤发红，并且感觉非常寒冷。持续暴露会导致受创部位的刺痛和麻木。当皮肤变暖时，你可能会感到疼痛和刺痛。亚冻伤不会给皮肤造成永久性伤害。”

　　But, frostbite can. It can even lead to loss of tissue and limbs.

　　但是冻伤会。它能造成失去组织和四肢。

　　Hypothermia

　　失温

　　The most serious danger is hypothermia. Hypothermia is when the body temperature has fallen below 35 degrees Celsius or about 95 degrees Fahrenheit. This happens when your body can not produce enough energy to keep the body warm enough.

　　最严重的威胁是失温。失温是指体温降到35摄氏度或95华氏度以下。当身体无法产生足够能量维持体温时就会发生这种情况。

　　Hypothermia can kill you. There are several signs to watch for before it is too late.

　　失温会让你丢命。在为时已晚前可以关注以下迹象：

　　difficulty in movement

　　运动障碍

　　difficulty in thinking

　　思维障碍

　　slowed reactions

　　反应迟缓

　　unclear speech

　　口齿不清

　　cold feet and hands

　　手脚发冷

　　shivering

　　身体发抖

　　sleepiness

　　嗜睡

　　Falling on ice

　　冰上滑倒

　　However, Dr. Sampson says it is ice that creates the biggest risk for workouts outside when it is very cold. People don’t see the ice, step on it and fall.

　　然而，桑普森博士表示，当天气寒冷时，户外锻炼最大的风险是冰。人们没看到冰，踩上去滑倒。

　　Dress properly

　　正确着装

　　But if you are dressed right, you can exercise safely in low temperatures.

　　但是如果你着装正确，就能在低温下安全地锻炼。

　　Experts on several health websites say it is important to dress in layers.

　　几家健康网站的专家表示，分层穿衣很重要。

　　The layer closest to the body should be made of a material that takes moisture away from the body. The next layer should be a material that traps heat, such as wool. And finally, the outer layer should be water resistant.

　　最贴近身体的衣物应该用排汗材料制成。下一层衣物应该用保暖材料，例如羊毛。最后，外层衣物应该是防水的。

　　Of course, don’t forget gloves, hat, good socks and shoes. When it is really cold, a scarf or face mask will protect your skin and lungs.

　　当然，不要忘记手套、帽子、合适的袜子和鞋子。当天气非常冷的时候，戴上围巾和口罩可以保护你的皮肤和肺。

　　Check the weather forecast

　　关注天气预报

　　Temperature is not the only things that will affect your outdoor workout. It is also important to consider wind and water.

　　温度并非影响户外锻炼的唯一因素。关注风和雨也很重要。

　　Wind can go through your clothing and steal the layer of warm air that surrounds your body. If you get wet, you may not be able to keep your body temperature high enough.

　　风能穿过衣物，带走你身体周围的热气。如果身上弄湿了，你可能无法维持足够高的体温。

　　So, if you are a generally healthy person, do not think you must move your workouts indoors in winter. As long as you dress properly, drink enough water and exercise safely, you can get a lot out of a cold-weather workout.

　　所以，如果你身体基本健康，不要认为冬天只能在室内锻炼。只要你穿着得当，喝足够的水，并安全地锻炼，你就能从寒冷天气的锻炼中受益良多。