Bodily Changes in Pain, Hunger, Fear and Rage
Walter Cannon, 1915
Why does a bite get stuck in your throat after a quarrel, and why do your hands shake before a speech? In 1915 Harvard physiologist Walter Cannon looked inside: into the stomachs, blood and adrenal glands of frightened and enraged animals and of anxious people. The book from which the idea of “fight or flight” grew explains how fear, rage, pain and hunger reshape the body, and why it needs this ancient alarm.
Who it is for
For people whose mouth goes dry before an exam, whose appetite vanishes after a quarrel, and whose heart pounds at the worst possible moment, and who want to understand what the body is doing in those minutes and why.
Whoever lets fears, worries and anxieties upset digestion when nothing can be done is, in effect, putting the body on a war footing, though there is no one to fight.
Sugar on the bench
Picture the autumn of 1913, the last and most tense game of the American football season. Right after the match, Harvard physiologist Walter Cannon and a colleague checked the urine tests of twenty-five players from the university team. Sugar turned up in twelve of them. Five of those were substitutes who never got onto the field. Sugar also turned up in the one spectator who was tested, a fan who was simply worried in the stands; the next day his sugar was gone.
What happens inside a person who sits on the bench and only worries? For several years Cannon looked for the answer where no one can see from outside: in the stomach, in the blood, and in two small glands above the kidneys, called the adrenal glands. In 1915 he gathered these experiments into a book, Bodily Changes in Pain, Hunger, Fear and Rage, and wrote it so that a reader with no medical training could follow it.
His central idea is this: fear, rage and pain set off the same chain of changes inside you, and every link in it helps the body in a fight. Cannon writes about “the needs of struggle or flight,” and from that idea grew the famous phrase “fight or flight.”
The book is more than a hundred years old, and science has since refined some of its explanations. But the picture itself has held. Ahead come a dog that saw a cat and stopped digesting its dinner, students after exams, a man who swallowed a rubber balloon for science, and the question Cannon asked in the middle of a war: what to do with the ancient readiness to fight when there is no one to fight. Let’s start with the stomach.
The dog saw a cat and stopped digesting
Russian physiologist Ivan Pavlov showed that the stomach starts working before food arrives. A dog that happily chewed its favorite food needed only the taste and smell to get gastric juice flowing. So, appetite is not a whim but the first step of digestion.
The researchers Bickel and Sasaki repeated this experiment and added one detail. Usually their dog produced almost 67 cubic centimeters of juice in twenty minutes. Once, before feeding, the dog was shown a cat, and it flew into a rage. The cat was taken away, the dog was calmed down, and it went back to eating eagerly. But in the same twenty minutes, only 9 cubic centimeters of juice collected. Another time the cat was shown in the middle of a meal, and the juice nearly dried up for the next quarter of an hour. The rage had long since faded, yet the stomach still stood still.
Cannon saw the same thing on an X-ray screen. In calm cats, waves of contraction ran across the stomach; in worried ones it went still. Once a cat with kittens suddenly grew anxious, and the waves stopped. They started again only when she was stroked and began to purr.
The same happens in people. Cannon tells of a woman who came to Boston to see a doctor. She spent the night before her examination in anxiety: her husband had got drunk and was carousing all night. In the morning, last night’s dinner was still in her stomach. After a full day of calm rest, her stomach worked as usual.
From this comes Cannon’s simple advice. If a child has just cried hard or raged, don’t rush to coax them into eating: the food will simply sit there. And for a sick person who has lost their appetite, a nicely served meal helps: small portions, neat dishes, a flower beside the plate. According to Cannon, that can decide whether the person starts to regain their strength.
About the author
Walter Bradford Cannon (1871-1945), American physiologist and professor at Harvard University. He studied how feelings change the work of the internal organs, and later coined the term homeostasis.
All books by this author: Walter Cannon
Terms from the book
- James
- Adrenal glands
- vagus nerve
- adrenaline
- glycogen
- second wind
- Pavlov: Ivan Petrovich Pavlov (1849-1936), Russian physiologist, Nobel Prize laureate in 1904 for his work on digestion.
- Bickel: A physiologist of the early twentieth century. Together with Sasaki, he studied how strong feelings suppress the secretion of gastric juice in dogs.
- Sasaki: Bickel’s co-author in the 1905 experiments on how rage stops the secretion of gastric juice.
- autonomic nervous system: The part of the nervous system that controls internal organs, blood vessels and glands without conscious will.
- sympathetic division: The part of the autonomic nervous system that, under strain, speeds up the heart, widens the pupils, narrows the blood vessels of the abdomen and slows digestion.
- adrenin: The name Cannon used for the substance of the adrenal glands. Today it is called adrenaline or epinephrine.
- tripod of life: An old expression that Cannon quotes: the heart, lungs and brain, without which life is impossible for even a minute.
- Gruber: Cannon’s student who in 1913 studied how fatigue, blood pressure and adrenaline change the sensitivity of a muscle.
- bronchi: Branching tubes in the lungs through which air passes. The smallest of them are called bronchioles.
- Washburn: Cannon’s student. In 1911, together with Cannon, he recorded the contractions of his own stomach during hunger, using a swallowed rubber balloon.
All terms
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