成功人士缘何爱上马拉松？

    但是凯娜里克说最有意思的发现是，身材走样的人都会被认为比经常锻炼的人老5岁。“我想，那是一种年轻有活力的感觉，”凯娜里克说，而这同样也有助于延年益寿。

    她的研究还有另一个发现，那就是将持续保持锻炼的老鼠强制停止运动后，出现的症状如同强制停止注射吗啡的老鼠一样。所以，富于进取心的人开始可能只会参加半程马拉松，然后就觉得可以再多跑一段，于是就是全程马拉松，接下来就是超级马拉松，最后就可以完成铁人三项了。

    “身体到达一定极限之后就会有一种上瘾的感觉，”凯娜里克说。“如果他们冒着大雪跑步，或是连跑100英里穿越死亡峡谷时，你会发现，一定有某些其他的东西在发挥作用。”

    布朗说，要看一个人对耐力运动是不是发自内心的热爱，就问问他“除了运动员，你在生活中还有其他身份吗？”这个问题至关重要。虽然“躺在功劳薄”上是个贬义词，但在一个大多数人都身材走样的社会中，倘若你既能跑完10公里还能赚到六位数薪水，绝对是件了不起的事。

    译者：唐昕昕

    But Kanarek says what she found most interesting was that the less fit were deemed about five years older than the intense exercisers. "I think there's that desire to feel younger," says Kanarek, to perhaps stave off mortality.

    Couple that with another of her research findings -- namely that rats weaned off of intense exercise go through classic symptoms of withdrawal very similar to the kind experienced by rats given morphine -- and you can start to see how an achievement-oriented sort might start with a half-marathon, but then decide she needs to do more. A marathon. An ultra-marathon. An Ironman.

    "When people become really extreme, they do get into this addictive pattern," says Kanarek. "If they're running when it's snowing, or doing ultras -- running 100 miles through Death Valley -- there's something else going on there."

    The key to recognizing if one's attitude toward endurance events is healthy or not, says Brown, is to ask "Do you have an identity in your life other than that as a performer? That's essential." While "resting on your laurels" has a negative connotation, in a society where many people are out-of-shape, being able to run a 10K -- and earn six figures -- is pretty good too.