418 



PHYSIOLOGY OF STRESS 



eluding autonomic) responses to sensations, 

 with awareness or "consciousness" of the 

 presence of these physiological adjustments. 

 The initial physiological change and the emo- 

 tional reaction to the change may in turn 

 have secondary effects upon the central nerv- 

 ous system. All may alter the background 

 of awareness or consciousness, and, when 

 they have acquired "value'' for the individual 

 on the basis of association and "condition- 

 ing," may contribute to his "affective state." 



B. Stresses Developed in Performance of 

 Duty. A second type of stress is that due 

 to demands placed on the performance of 

 the organism. These are the stresses at- 

 tributable to the rigors of performance of 

 "duty," such as effort, fatigue, hunger, loss 

 of sleep, etc. Emotional response may here 

 be elicited on recognition of the demands of 

 the situation. Further, different emotional 

 responses may occur subsequently as the 

 seaman becomes aware of his inadequacy or 

 waning mental and physical ability to meet 

 demands. Again, both the physiological con- 

 sequences of the activity involved in per- 

 formance and the emotional reaction to those 

 effects may secondarily affect the central 

 nervous system. 



C. Emotion under Stress. A third type 

 of stress is that initially involving a psycho- 

 logical response, for example as in depth 

 bomb attack, with perception of the situa- 

 tion and the recognition of danger. Again, 

 the physiological consequence of the emotion 

 may secondarily feed back and affect the 

 central nervous system. The fact that the 

 perception of a dangerous situation may 

 initiate processes in the brain which may dis- 

 charge peripherally to increase heart rate, 

 raise blood pressure, produce adrenaline, etc., 

 has for years been the subject matter for 

 those studying the "expressive" aspects of 

 emotional response. The possibility that the 

 autonomic, humoral and other changes asso- 

 ciated with emotion may "feed back" and 

 affect the vascular, chemical, and neuronal 

 conditions of the brain has received less 



consideration. Of thepossible importance of 

 these "feedback" effects in accounting for 

 the "functional" effects of emotion we shall 

 speak in Section II C. 



In the psychological reactions to the per- 

 ception of danger the usefulness of the or- 

 ganic response may not always be obvious, 

 but its physiological basis is readily under- 

 stood. The increased muscle tonus, the in- 

 creased heart rate, the increased blood pres- 

 sure, the increased sweating, the adrenahne 

 secretion, associated hyperglycemia, changes 

 in the pituitary, and many of the other 

 physiological effects which may occur in re- 

 sponse to a purely perceptual recognition 

 of danger are reactions which would be useful 

 if the submariner were engaged in severe bodily 

 exertion to meet the threatening situa- 

 tion. These are the changes which, if they 

 occurred in support of the actual doing of 

 work, would be regarded purely as prepara- 

 tory or facihtative. That these changes oc- 

 cur in a perceptual situation in which the 

 conditions do not require or permit violent 

 expenditure of energy, and that they may, in 

 the absence of an overt function, become 

 disorganized and inappropriate, is apparently 

 the only reason for labeling them "emo- 

 tional" activities rather than merely homeo- 

 static adjustments. The unique feature dis- 

 tinguishing emotion from other activity or 

 "work" here hes in the fact that organic 

 changes which normally would be organized 

 to facihtate performance are present but 

 that the activity or "work" is lacking. We 

 do not incHne to the view of James and 

 Lange that a man fears a bear because he 

 runs away from it. He experiences fear, 

 rather, we beheve, because he is producing 

 organic physiological changes suitable for 

 fleeing but in the circumstances is hindered 

 effectually from doing so, and the organic 

 changes, in consequence, are excessive, in- 

 appropriate, and may be disorganized. The 

 hunted human animal lying in his bunk, 

 walking without shoes, or talking in whispers 

 while a stalking subchaser "pings" at his boat 



