"It's physiological and it's emotional." "Physiologically,we have a tendency when we come into a situation that seems dangerous we get a lot of chemicals flowing through our bodies to help us stay alert, to be able to act if we need to act.

VOA: standard.2010.07.01

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

And there's increasing research that shows a direct but poorly-understood link between relationships and physiological processes in the body.

VOA: standard.2010.07.29

Nor does empathy suggest a physiological "reason" for yawning (after all, we yawn when alone), though Dr. Provine thinks that it may be "a response to and facilitator of change in behavioral or physiological state, " maybe synchronizing a group of people about to embark on a behavioral transition.

WSJ: Matt Ridley on Why You Just Yawned | Mind & Matter

But that said, from a physiological standpoint, Bryant says the afternoon may be a better time to engage in more explosive exercises, such as kickboxing or racquetball.

FORBES: Best Time To Hit The Gym

Ms Sandford said that if addiction to smoking was a mental, as well as a physiological, dependence then it was logical that anti-depressants could could play a role in helping smokers to quit.

BBC: Smoking