Stress in Fight & Flight

When primitive man found himself confronting a savage beast, according to the great physiologist Walter B. Cannon (1871-1945), his hormone system poured out a flood of adrenaline to equip him equally well for "fight or flight." Now it is known that the hormone system is far more complex. Besides adrenaline, and perhaps more important, there are the hormones produced in the adrenal gland's cortex--hydrocortisone and closely related compounds. And a new study indicates that today's fighting man, far from flooding himself with such hormones in times of stress, actually finds subconscious ways to suppress them.

Waste Not. To carry out the study, the U.S. Army sent Captain Peter G. Bourne to Viet Nam. Although he is a psychiatrist, Dr. Bourne decided to use biochemical indicators of servicemen's reactions to combat and the threat of death. In Saigon he made friends with the medical corpsmen of helicopter ambulance crews since they were medically oriented and most likely to cooperate in his demanding routines. They agreed to run a daily check list of their emotional changes.

Most important, they agreed not to let a drop of their urine go to waste for three weeks, though this meant having a technician follow them around in offduty hours. Dr. Bourne wanted these round-the-clock specimens because the chemicals in them would reveal what levels the stress hormones had reached each day. Despite some unavoidable misses, he got 76 day-and-night samples from the group. He froze part of each and sent the specimens by air to Washington for analysis.

The delicate biochemical readings proved to be remarkably uniform for all the men, and differed little between flight-stress days and relaxed, off-duty days. They tallied closely with what Dr. Bourne deduced from flying and talking with the men on dangerous missions. On the average, they showed less reaction to stress than do draftees undergoing basic training at Fort Dix, NJ. When the stress and danger were real, the men suppressed their anxiety and related reactions. One man, an unquestioning Roman Catholic, was convinced that God would look after him. Another, with a parimutuel mentality, had painstakingly taken the reported casualties and calculated the chance that any one man would be killed or injured on any single day. The risk, he concluded, was so slight that he could stop worrying. All the men, no matter how often they talked of near misses by Viet Cong ground fire, had convinced themselves of their own invulnerability.

Evening Peak. Since the flying medics were a special breed, exposed to enemy fire for only an hour or two at a stretch and not every day at that, Dr. Bourne wanted to study the reactions of ground forces in constant danger and therefore under continuing stress. To do this, he and Technician William M. Coli joined a Green Beret detachment of two officers and ten enlisted men stationed at Due Co, southwest of Pleiku and only a few miles from the Ho Chi Minh trail. The Green Berets had good reason to be edgy. The study began during the dark of the moon. The monsoon was beginning. Ho's birthday was approaching. And U.S. intelligence kept warning Captain Wells E. Cunningham that an attack on his tiny force was imminent.

It was difficult to get specimens under these conditions. Says Captain Bourne: "We practically said, 'Let us have your urine while you're being shot at.' " As it happened, all Viet Cong attacks were aborted before they could reach the camp. But that made no difference to the Bourne study. The men were under relentless cyclic stress, which reached a peak every evening with the prospect of a night attack. One day when intelligence said that an attack was expected, 30% of the G.I.s developed "the G.I.s"--diarrhea. But all, like the medics, showed normal or subnormal levels of stress hormones.

Captain Cunningham (who was killed in action a week after the Bourne team left) and his executive officer both had 30% higher levels of stress hormones than the enlisted men. Explains Dr. Bourne: "The officers were worrying about their men; the men were worrying only about themselves." In all probability, he says, any of the men studied would have had a higher stress-hormone level back home on the eve of a tough college exam than they showed in Viet Nam.

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