奥运新资讯：对决霍顿前夕，孙杨感冒的消息在微博掀起热议。不少网友力挺孙杨，指出孙杨在8日比完200公尺自由式夺金后就感冒了，并非与霍顿对决前夕才生病。据悉，孙杨并未因感冒影响到训练行程，在服药后几小时便开始训练，但他的感冒是否影响到与霍顿的世纪之战，仍是未知数。
小编由此想到了运动与感冒的话题，“Exercise and the Common Cold”。
ACSM（美国运动医学会）曾对于运动与感冒进行过科学总结，认为：
A cold is an inflammation of the upper respiratory tract caused by a viral infection. The common cold is probably the most frequently occurring illness in humans worldwide. More than 200 different viruses cause colds, and rhinoviruses and coronaviruses are the culprits 25-60 percent of the time. Rhinovirus infections often occur during the fall and spring seasons, while the coronavirus is more common during the winter.
The U.S. Centers for Disease Control and prevention estimates that over 425 million colds and flus occur annually in the United States, resulting in $2.5 billion in lost school and work days, and in medical costs. The average person has two or three respiratory infections per year. Young children suffer from six to seven annually.
美国疾病预防控制中心估计，每年超过4.25亿人次的美国人会发生感冒或是流感（流行性感冒），由此造成的医疗支出高达250亿美元。一般成人每年发生2～3次，儿童发生率较高，每年6～7次。
Can a walk each day keep colds away?
People who exercise report fewer colds than their inactive peers. For example, one recent survey revealed that 61% of 700 recreational runners reported fewer colds since beginning to run, while only 4 percent felt they experienced more. In another survey of 170experienced runners who had been training for 12 years, 90% reported that they definitely ormostly agreed with the statement that they "rarely get sick."
To test this belief scientifically, two well-controlled studies with young and elderly women were conducted. In both studies, women in the exercise groups walked briskly 35-45 minutes, five days a week, for 12-15 weeks, with the control groups remained physically inactive. The results were in the same direction reported by fitness enthusiasts -- walkers experienced about half the days with cold symptoms as the sedentary controls.
Other research has shown that during moderate exercise, several positive changes occur in the i－mmune system. Although the immune system returns to pre-exercise levels very quickly after t－he exercise session is over, each session represents a boost that appears to reduce the risk o－f infection over the long term.
研究结果显示：运动不仅可以而减少感冒发生，而且发生感冒后，恢复得更快。而且通过适度的运动，我们的免疫系统会发生积极的改变。长期科学的锻炼，增强了我们的免疫系统，降低了发生感冒的风险。
Can too much exercise hurt?
Among elite athletes and their coaches, a common perception is that heavy exertion reduces resistance to colds. During the Winter and Summer Olympic Games, clinicians report that "upper respiratory infections abound" and that "the most irksome troubles with athletes are infections."
To determine whether these anecdotal reports were true, 2,311 marathon runners who ran the 1987 Los Angeles Marathon were studied. During the week following the race, one out of seven runners became sick, which was about five times the rate of runners who trained for, but did not run, the Marathon. During the two-month period before the race, runners training more than 60 miles a week doubled their odds for sickness compared to those training less than 20 miles a week. Researchers in South Africa have also confirmed that after marathon-type exertion, runners are at a high risk for sickness.
The immune systems of marathon runners have been studied under laboratory conditions before and after running 2-3 hours. A steep drop in immune function occurs lasting at least 6-9 hours. Several exercise immunologists believe this allows viruses to spread and gain a foothold.
“过量训练带来的极度疲劳会降低人的抵抗力，也就是说大运动量训练可能增加发生感冒的风险。”比如，在夏季和冬季奥运会上，运动员村的医生们都反映这么一个现象：运动员在参加奥运会期间出现感冒比比皆是，这也是运动员最大的烦恼。
Rest or exercise when sick?
感冒时休息还是运动？
Most clinical authorities in the area of immunology recommend:
• If one has common cold symptoms (e.g., runny nose and sore throat without fever or general body aches and pains), intensive exercise training may be safely resumed a few days after the resolution of symptoms.
• Mild-to-moderate exercise (e.g., walking) when sick with the common cold does not appear to be harmful. In two studies using nasal sprays of a rhinovirus leading to common cold symptoms, subjects were able to engage in exercise during the course of the illness without any negative effects on severity of symptoms or performance capability.
• With a symptom complex of fever, extreme tiredness, muscle aches, and swollen lymph glands,2-4 weeks should probably be allowed before resumption of intensive training.
• In general, if the symptoms are from the neck up, moderate exercise is probably acceptable and, some researchers would even argue, beneficial, while bed rest and a gradual progression to normal training are recommended when the illness is systemic. If in doubt as to the type of infectious illness, individuals should consult a physician.
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如果出现感冒症状（例如流鼻涕、喉咙痛，但无发热，也没有全身酸痛），症状消失后，再等两三天，然后再进行高强度运动是最安全的做法。
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感冒时，进行一些轻度运动例如走路，对身体是没有负面影响的。已经有两项研究表明，由鼻病毒导致的普通感冒，感冒者进行中低强度运动，没有出现感冒加重，普通的轻症感冒对于运动能力似乎也没有影响。当然，这并不是说鼓励感冒时参加剧烈运动。
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当出现发烧，身体极度疲劳，肌肉酸痛，以及淋巴肿大等较重感冒症状时，建议休息2-4周，身体完全恢复后再开始跑步。
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总体来说，如果感冒症状只是出现在脖子以上的部位，比如咽喉不适，鼻塞、流鼻涕等等，参加轻中度运动并不是完全禁止的。甚至学者争论说，相比躺在床上休息，轻症感冒时，少量运动，甚至更有利于恢复。如果发生流感这种传染性强的感冒，建议及时就医并进行治疗。
Practical applications
Although more research is needed, the American College of Sports Medicine (ACSM) supports the viewpoint that moderate physical activity (30 minutes a day, on most, if not all days of the week) exerts less stress on the immune system than does prolonged and intense exercise. Regular and moderate exercise lowers the risk for respiratory infections, a finding consistent with previous reports from ACSM urging people to exercise moderately for enhancement of health and disease prevention. Athletes who must train hard for competition can lower their risk of respiratory infection by following the guidelines listed in this report for keeping the immune system in good shape.
美国运动医学学院(ACSM)支持的观点：
适度的体力活动(每天30分钟,在大多时候,而不是每周每天)比长时间的剧烈运动而言，对免疫系统产生较少的压力；
定期和适度的运动可降低呼吸道感染的风险。
补充观点：
如果你在感冒时运动，有注意到有以下现象，请咨询相关专业人员：
●你的胸部感觉很闷
●出现咳嗽和喘息的症状
如果你出现下列症状，应立刻停止运动，请求紧急医疗帮助：
●感觉胸闷或胸口紧窒
●呼吸困难或者呼吸急促
●头晕眼花
●感觉身体不稳、失去平衡
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