Blood for Fight or Flight

When a man gets angry, his body prepares for a fight, and his heart speeds up. When a man is frightened, his body prepares for flight, and his heart speeds up. This much is familiar medical fact.

But a group of researchers at Ohio State University Hospitals wanted to know whether the body, in its responses to stress, distinguishes between anger and fear. And since it is known that the body's arousal mechanism depends heavily upon an outpouring of adrenalin, the researchers also wanted to know what would happen if the activity of the adrenal glands was suppressed.

The first problem, Dr. Willard S. Harris explained to the American Heart Association, was to devise an acceptable experimental setting in which volunteers could be subjected to forces inducing anger and fear. The Columbus team decided to do it under hypnosis. They got nine volunteers, eight of them graduate students at Ohio State and one a hospital patient. Each one had to have a plastic tube threaded through an arm vein into the heart, and a needle positioned inside an artery in the arm. In a half-dark, quiet room, the subjects were hypnotized. For ten to 15 minutes at a time, they were given suggestions calculated to make them angry or fearful. They had 45 minutes in which to relax and then they were awakened from hypnosis.

Fear and anger, Dr. Harris reported, produced the same sort of changes in the subjects' heart rate (up, on the average, from 65 to 98 beats a minute), breathing rate (up from 15 to an average of 35 and as high as 68 a minute), the heart's output of blood per minute (up an average of 33%), blood pressure (slightly elevated), and blood flow through the extremities (markedly increased). The only noteworthy difference between the effects of fear and anger was that in some subjects fear caused a somewhat greater increase in heart rate and output.

What would happen if the effects of adrenalin were blocked by another drug? The researchers found that the human body is resourceful enough to meet the emergency. If it does not speed up, the heart manages to increase total blood output by the simple device of increasing its output of blood per beat. The effect is the same: to give both brain and limbs an added supply of oxygen for fight or flight.

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