研究人員找出跑者愉悅感的原因Researchers ferret out reasons for runner’s high

You’ve probably had the feeling. Your running shoes are pounding the pavement--then suddenly your pain fades away, and you’re feeling euphoric. The runner’s high.

你大概有過這樣的感覺。你的跑鞋沉重地踩在路上─然後，突然間痛苦消散，你感覺愉快。跑者的愉悅感。

But that biological perk may be limited to mammals that evolved for endurance exercise--like us. So says a study in the Journal of Experimental Biology.

但是，那種生物性振奮狀態或許只限於經演化成適合耐力運動的哺乳動物─像我們人類。「實驗性生物學」期刊上的一份研究這麼說。

Researchers had humans and dogs--both natural-born runners--jog a half hour on a treadmill. Then they sampled their blood for endocannabinoids, some of the compounds thought to trigger the runner’s high.

研究人員讓人和狗在跑步機上跑30分鐘─這兩種動物都是天生的跑者。接著，採集他們的血液樣本，檢驗內生性大麻鹼，這種化學物質據信會引發跑者愉悅感。

As expected, humans and dogs had much higher levels after the run. But when sedentary ferrets took the same 30-minute trot, they had no spike in those feel-good molecules.

一如預期地，人和狗跑步後，血液中內生性大麻鹼都高得多。但是，定棲性貂鼠同樣跑30分鐘後，血液中這種產生愉悅感的分子數量卻沒有提高。

The authors say that’s because long-distance running could have helped our hunter-gatherer ancestors find more food--thus increasing their reproductive success. And they speculate that natural selection may have linked up a feel-good reward to that beneficial behavior.
報告作者說，這是因為長距離跑步可能幫助我們以打獵採集為生的祖先找到更多食物，從而促進他們繁殖成功。作者推測，物競天擇或許讓愉悅回饋機制與這種有利於生存的行為產生關連。

These days of course, this ancient trait won’t help us find extra calories--but it may encourage us to run ’em off.
當然，這種祖先留下來的天性，在今日不會幫助我們取得更多熱量，而是或許鼓勵我們擺脫卡路里。

新聞辭典：

ferret out：動詞片語，（經過仔細、持續調查後）查出、揭露。例句：It will take years to ferret out the truth.（要查出真相將花上數年時間。）

fade away：動詞片語，漸漸消失、凋零、衰弱。例句：Our parents are fading away as they get older.（我們的父母日漸年邁，身體正逐漸衰弱。）

perk：動詞，振作、活躍、恢復精神，打扮。名詞（俚語，常用複數形），小費、額外津貼或福利。例句：Try to perk yourself up with some exercise when you feel tired during the day.（白天覺得疲倦時，試著做些運動提振精神。）