Intense contraction of facial muscles, such as those used in signifying fear, heightens arousal.

面部肌肉因紧张而收缩会加强这种刺激，如人们感到恐惧时所表现出的肌肉收缩。

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Other triggers can include cold air, extreme emotional arousal such as anger or fear, and physical exercise.

其他诱因可能包括冷空气、愤怒或恐惧等极端情绪激发以及体育锻炼。

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For most, fear, anxiety, remembering, efforts to avoid reminders, and arousal symptoms, if present, will gradually decrease over time.

多数情况下，恐惧、焦虑、回忆、极力避开唤起创伤的事物，以及种种亢奋行为，都会随着时间消退。

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Here are humans who had to walk long distances potentially to find the food, kill the food at great risk to themselves; inspiring a cascade of physiological effects that have to do with fear and arousal and things like that, not to mention all the calories one would burn doing this kind of activity.

这些人可能需要走很远的路,去寻找食物,冒着巨大危险,杀死猎物,人们耗费能量以激活一系列生理效应,用以战胜恐惧,引发斗志,更不用说人们在狩猎的过程中,消耗的卡路里量了

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选