204 PHYSIOLOGICAL STUDIES 



eight blood stress factors examined, LDH (lactic dehydrogenase) provoked greatest interest, 

 since values for this enzyme are generally considered to be proportional to a degree of tissue 

 damage. Unfortunately, advanced stratifying techniques could not be utilized with the limited 

 facilities of Sealab 11; hence, the particular organ responsible for the observed LDH overpro- 

 duction could not be pinpointed. It would appear that stress indicators are probably the most 

 sensitive physiological warning signals available to topside monitors, and this fact will be 

 suitably exploited in future undersea experiments. 



In summary, it would appear that two important physiological observations are evident. 

 First, almost all physiological functions demonstrate a sharp deviation from baseline values 

 during the first three to five days of exposure in all Sealab experiments. Secondly, the accep- 

 ted indicators of physiological/psychological stress are generally elevated during the first few 

 days of exposure. These two provocative observations indicate an urgent need for additional 

 research in this area. 



