Instead, it is typically triggered by acute emotion or physical trauma that releases a surge of adrenaline that overwhelms the heart.

相反，它通常由剧烈的情感或身体外伤引发，患者肾上腺素水平骤然升高，心脏不堪重负。

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Cortisol and adrenaline are essential components of humans' 'fight or flight' mechanism - the neuro-biological response to stressful situations that has evolved through millions of years.

皮质醇和肾上腺素是人体对抗机制的必要组成部分，这种生物神经机能对于危险情势的反应已经进化了数百万年。

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A: the autonomic nervous system USES the hormone adrenaline, a neurotransmitter, or chemical messenger, to send signals to various parts of the body to activate the fight-or-flight response.

答：这套自动神经系统利用肾上腺激素(一种神经递质，或者称为化学信使)把信号发送到身体的各个部分，以便激活“斗争还是逃避”反应。

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At other times, Two-up would have to compete for players with the flashing lights of slot machines or the adrenaline of horse racing.

WSJ: Two-Up, A Game Australians Flip Over, Loses Luster When Legalized

Maybe it was the pent-up energy of being trapped in the van for so long, or the adrenaline rush of hurrying to the station, but Elliott Brood kicked out an incredibly rousing performance that Monday afternoon.

NPR: Elliott Brood: 'Death Country' At The Border

Last time I checked, bird watching doesn't do much to spark adrenaline or improve one's fitness.

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