霧霾天仍然可以適當鍛鍊

Walking or cycling is good for you even in polluted cities, researchers have found.

研究人員發現，即使在有空氣污染的城市，行走或騎車也是對健康有益的。

The health benefit of physical activity outweighs the harm caused by chemicals and dust puffed out by traffic and industry, according to Cambridge academics.

根據劍橋大學學者的研究，體育鍛鍊對健康的好處要大於汽車和工廠排放的化學物質和灰塵造成的危害。

Air pollution is a major problem in British cities, and is estimated to contribute to 40,000 early deaths in Britain every year.

空氣污染是英國城市的主要問題，據估計，英國每年有四萬人因空氣污染而過早死亡。

People who exercise in polluted areas are thought to put themselves at increased risk, because they take deeper breaths, inhaling more of the toxic pollution and particles that do such damage.

人們通常認爲，在污染區域進行體育鍛煉會增加患病風險，因爲鍛鍊時呼吸更深，會吸入更多有毒污染物和顆粒物，而這些污染物都對健康有害。

But a new study, published in the journal Preventive Medicine, suggests that the act of exercising outweighs this risk, because physical activity reduces the risk of diseases such as diabetes, heart disease, and several cancers.

但是，一項發表在《預防醫學》期刊上的最新研究表明，鍛鍊帶來的益處遠甚於它帶來的風險，因爲體育活動可降低患糖尿病、心臟病和某些癌症的風險。

Experts at the Centre for Diet and Activity Research - a collaboration between the universities of Cambridge and East Anglia - used computer simulations to compare the risks and benefits of exercising in polluted areas around the world.

飲食與鍛鍊研究中心的專家使用電腦仿真技術，比較了在世界各地污染地區進行體育鍛煉的風險和益處。飲食與鍛鍊研究中心由劍橋大學和東安格利亞大學合作建立。

Only 1 per cent of cities are so polluted that the risks start to overcome the benefits of physical activity after half an hour of cycling.

只有1%的城市不符合上面的結論——這1%的城市因爲污染太嚴重，以至於騎行半個小時後，體育鍛煉的風險就開始超過健康收益了。

Study leader Dr Marko Tainio, of the University of Cambridge, said: ‘Our model indicates that in London health benefits of active travel always outweigh the risk from pollution.

領導該研究項目的劍橋大學馬可·泰尼奧博士說：“我們的模型顯示，在倫敦，體育活動的健康收益總是大於污染的危害。

‘Even in Delhi, one of the most polluted cities in the world – with pollution levels ten times those in London – people would need to cycle over five hours per week before the pollution risks outweigh the health benefits.

“即便在世界上污染最嚴重的城市之一印度德里，污染水平是倫敦的十倍，人們每週仍然可以騎行五個多小時，健康收益大於風險。繼續增加鍛鍊則會危害健康。

‘We should remember, though, that a small minority of workers in the most polluted cities, such as bike messengers, may be exposed to levels of air pollution high enough to cancel out the health benefits of physical activity.’

“然而我們也要記住，在污染最嚴重的城市裏，有一小部分工人，比如騎自行車的郵差，可能長時間暴露在空氣污染嚴重的環境中，就抵消了體育運動的益處。

Senior author Dr James Woodcock added: ‘Whilst this research demonstrates the benefits of physical activity in spite of air quality, it is not an argument for inaction in combating pollution.

該研究的資深作者詹姆斯·伍德科克補充說：“儘管這項研究證明，即使在空氣質量差的情況下，進行體育運動也是有好處的，但並不意味着我們在對抗污染方面就可以不作爲。

‘It provides further support for investment in infrastructure to get people out of their cars and onto their feet or their bikes – which can itself reduce pollution levels at the same time as supporting physical activity.’

“它進一步說明，我們要加大對基礎設施的投入，鼓勵人們從汽車上下來，靠雙腳或自行車行進——這樣既可以降低污染水平，也可以加強體育鍛煉。”