GRE阅读范文之揭秘奔跑锻炼上瘾的秘密
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小编：天空 1184Running speeds were thus set at 2.5 metres a second for people, 1.83 for dogs and 0.84 for ferrets.
这样设置的结果便为：奔跑速度为人类2.5米/秒，狗1.83米/秒，雪貂0.84米/秒;
Walking speeds were set at 1.25 metres a second for people and 1.1 for dogs.
行走速度为人类1.25米/秒，狗1.1米/秒。
The ferrets proved too easily distracted to walk consistently on the treadmills and were thus left to sit quietly in their cages for this part of the study.
雪貂由于太易分心，没办法让它持续在跑步机上行走，所以在进行该部分实验时它们被留在了笼中静静地坐着。
Each participating animal ran for one session and walked for one other, and did so on separate days, to avoid exhaustion.
每只动物会跑一段走一段，为了避免动物们出现筋疲力尽的情况，实验是分成几天进行的。
Before and after each session, blood was drawn from each and the endocannabinoid levels in it were measured.
在实验前和试验后，动物们都会被抽血以检验其中的endocannabinoid水平。
The researchers report in the Journal of Experimental Biology that, after 30 minutes of walking, participants' endocannabinoid levels did not rise.
研究人员在《生物学实验》杂志中提到，在经过30分钟的行走之后，参加实验的动物的endocannabinoid水平并没上升。
After running, however, the average human's endocannabinoid levels rose from 2.4 picomoles per millilitre to 6.1.
然而在奔跑过后情况则有所不同：那10个人的平均endocannabinoid水平从2.4 pmol/ml上升到了6.1 pmol/ml。
Dogs showed a similar trend, with levels rising from 2.4 pmol/ml to 8.0.
狗的变化趋势与人类似---由2.4 pmol/ml升至8.0 pmol/ml。
Ferrets were different. Although they did show an increase, from 3.0 to 3.9 pmol/ml, this was not a statistically significant rise.
唯独雪貂例外。他们的endocannabinoid水平虽亦有所上升-3.0 至 3.9 pmol/ml，但仍处于统计学上可不被纳入考虑的范围内。
These findings suggest that dogs experience a runner's high but ferrets do not.
这些发现表明狗中同样存在着赛跑者的亢奋现象，而雪貂则没有。
Dr Raichlen argues that it makes sense for ferrets not to have systems that reward cardiovascular activity, since such exercise consumes a lot of energy, may cause injury, and is not crucial to the stealthy hunting technique of sneaking down burrows and killing rabbits in their sleep.
看来雪貂体内并不存在对心血管活动进行阳性强化刺激的系统，Raichlen博士认为这对雪貂的发展同样是有意义的，要知道太剧烈的运动会消耗掉过多的能量， 甚至引发受伤，且这并非是雪貂捕猎技术中的关键-它们一般只需偷偷溜进兔子窝并在兔子们熟睡时将其杀死即可。
What is not clear is whether the endocannabinoid reward is an ancient mechanism that has been lost on branches of the mammalian tree that do not need it, or is something that evolves quickly in species which become active.
仍有待考证的是，究竟这种endocannabinoid刺激机制是从远古时代起即为哺乳类动物所拥有，还是从某些活跃的个别物种中进化出来的?
Given that humanity's arboreal simian ancestors would presumably have had little need to run, it is probably the latter.
鉴于人类的祖先—类人猿是树栖动物，据推测它们很少有奔跑的需要，因此正确结论很可能是后者。
But to be sure Dr Raichlen will need to put animals far less co-operative than ferrets on the treadmill.
但若要确认此假设，Raichlen博士需将更多如雪貂般不太合作的动物哄上跑步机。
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