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It is customary to treat stress with suspicion: you can find hundreds of manuals on how to get rid of it or drown it out. Maybe it’s better to make friends? In this material, we tell everything about stress (spoiler: it’s not so bad)
When we accidentally touch a hot pan for the first time, we experience stress. And when we get up under the shower with ice water – too. The first kiss, the first trip to school, the first cry of a child – stress. Even submitting this article is stressful, and maybe reading it is stressful for some too. It is customary to treat stress as an enemy, but it, meanwhile, can be useful. And most importantly, he almost never leaves us.
The troubles of lab rats
Hungarian-Canadian endocrinologist Hans Selye, while studying at university, noticed that some patients complaining of completely different diseases often show the same pool of symptoms – they just “look sick”. Features of a particular disease (tuberculosis, oncology or burns) appear later, and at first all complaints are reduced to a typical vague weakness.
In 1936, Selye was working with laboratory rats in Montreal. He injected them as an experiment with a hormone isolated from the ovaries of cows. The rats reacted to the injection rather strangely: they died suddenly, and at autopsy they found bloody ulcers, swollen adrenal glands and shrunken thymus glands, spleens and lymph nodes. The researcher tried other combinations of injections – saline, a hormone from a bovine placenta, an extract from the kidneys and spleen. The result was the same. Whatever was injected into the rodents, they got sick, and each time in a similar way.
Selye tried other unpleasant influences – extreme heat and cold, physical exertion, loud noises, toxic substances. The scheme remained the same: within 48 hours after such manipulations, muscle tone decreased in laboratory animals, an ulcer developed, and suppression of the immune system began. Then they died. Then Selye proposed a paradoxical explanation: death was not at all due to toxic substances or physical exhaustion, but due to experiences. The rats were simply scared of the injections.
“I found that any damage does the same thing,” Selye explained. “The obvious cause of illness is often infection, intoxication, nervous exhaustion, or simply old age, but in fact, hormonal failure seems to be the most common end-cause of death.”
The silent and almost imperceptible medical debut of the biological concept of stress took place in 1936, when Selye published a short note in the journal Nature entitled “A Syndrome Caused by Various Harmful Agents.” In his article, the scientist described the general adaptation syndrome – the body’s reaction to the external and internal demands placed on it, called “stressors”. In the 1950s, they began to talk a lot and often about stress, and despite the fact that further researchers largely refuted Selye’s conclusions or significantly supplemented them, it is customary to call him the “father of stress.”
What are stressors
The stressors we encounter can be completely different: a fall from the stairs, a fire, a quarrel with a friend, a failure at work, strong physical exertion – almost the entire list of actions that a person performs in his daily life.
Mikhail Zenko, specialist of the Laboratory for the Regulation of the Functions of Brain Neurons, Institute of Physiology named after I.P. Pavlov RAS:
“What in ordinary life is called stress, in fact, a stressor is any effect on the body that brings any of its processes out of balance (homeostasis). Stress, the stress response, or, as Hans Selye originally called it, the “general adaptation syndrome” is the body’s own response to such exposure. The most important property of any stress response is its non-specificity. It should be understood as follows: no matter what exactly happened to the body – injury, promotion, cold, hunger, infection, excitement before a date, winning the lottery – the acute response of the body will be the same, the ancient stress response systems will lead it to state of alert.”
According to the nature of the actions, stressors are divided into:
- activity stressors (competitions, skydiving, space flights),
- assessment stressors (memories of grief experienced, waiting for an injection, creating works of art),
- inconsistencies in activities (conflicts in the family or at work),
- physical and natural (darkness, loud sound, pitching).
Small children ask their parents to read them a fairy tale before going to bed and they constantly choose the same one. A tired father or mother, who does not really want to reread what is already known for the twentieth time, offers something new. But the child is crying: it is the old fairy tale that is needed. Surprisingly, stress is also to blame here. A child who is just getting to know the world experiences a lot of it, his whole body is constantly mobilized to meet potential stressors. Of the total amount of information that we receive throughout life, a huge percentage falls on the first 5 years. Therefore, in the evening, the baby wants something familiar, because during the day he was tired of the new. Adults also often want the familiar – this is the secret of the popularity of multi-series franchises. We know for sure that in the new film from the Harry Potter line, old characters and old scenery are waiting for us, which is why we are so happy to escape into the world of magic from the stresses of everyday life.
Stressors of different nature are perceived by different brain structures and trigger specific responses. The hypothalamus, the regulator of the neuroendocrine system, is involved in the assessment of the stressor, on which the content of stress hormones – adrenaline and cortisol – in the blood depends. If the nature of the stressor is such that, in addition to physiological changes in homeostasis (for example, a decrease in blood glucose levels), it causes some specific conscious sensations (pain from a fall or burn), the involvement of the hypothalamus and structures of the limbic system increases. Selye and his early followers did not yet know this. The first work on the topic – by Patsak and Palkovich – was published only in 2001.
Stages of stress
Selye found that the animal organism reacts to all types of stimuli in the same way – with three symptoms. They went down in history as the “Selye triad”: an increase in the cortical layer of the adrenal glands, a decrease in lymphatic structures, ulcers on the gastric mucosa. In addition, the scientist divided the stress response into three consecutive stages.
- When a stressor first appears, it activates anxiety stage. If our body is a castle, then stress is a sudden attack that should be repelled. First, the level of resistance of the organism decreases, some somatic and vegetative functions are disturbed. Then the body, as if recollecting itself, mobilizes reserves and turns on the mechanism of regulation of protective processes. If the protection is sufficiently effective, then the anxiety subsides, and the body returns to normal operation. Most of our stresses do not go beyond this stage.
- next stage, stage of resistance (resistance), occurs if the stressor acts for a long time. For example, the enemy army stands in front of the castle for a month. In this case, our body tries to redistribute reserves, seeks to use them in a balanced way against the background of system stress. He understands that he will sit in the blockade for a long time.
- Following the resistance exhaustion stage. It occurs if the stress is too long and excessive. The body can no longer fight. Adaptation reserves are decreasing. The body’s resistance decreases, it becomes more and more difficult for it to resist stress and, most likely, it gives up.
Imperfect theory
Before Selye’s discovery, scientists believed that certain diseases lead to certain physiological pathologies – and that’s it. He also discovered that stress also plays a role in any illness, and sometimes even a decisive one. It was the nonspecificity of the reaction that became the revolutionary feature of Selye’s theory of stress. Although subsequent scientific experiments showed that his somewhat radical idea was not entirely correct, he opened the door to a new area of u1949bu1953bresearch – scientists around the world began to study the connection of the stress response with chronic diseases (for example, arthritis, diabetes and heart disease). From XNUMX to XNUMX, Hans Selye was nominated annually for the Nobel Prize.
Selye’s theory sometimes led scientists down the wrong path. For example, until the end of the 2005th century, stomach ulcers were explained by stress. But in XNUMX, Australians Robin Warren and Barry Marshall received the Nobel Prize for proving the infectious nature of the disease. They discovered its causative agent, the now well-known bacterium Helicobacter pylori. Yes, stress can increase the process of ulcer formation. But it is still not its root cause.
Stress is good and bad
Although Selye was fluent in at least eight languages, his choice of the word “stress” to describe the syndrome he discovered was unfortunate. He himself said that if he had tried to be more precise, he would have used the word “strain” (strain). The scientist understood that with only unfortunate terminology, he gave stress the glory of what to fear and what to avoid. Stress management aids, bath bombs, soothing, relaxing candles, meditations, information detoxes, anti-stress toys – the world has declared a war on stress, which is still going on.
Selye argued that stress is a “seasoning for life.” Stress, in fact, performs the function of adaptation to change. “Even in sleep, our heart still needs to beat, we still need to breathe, our adrenal system still responds to dreams, we are still under stress,” Selye told the Canadian Medical Hall of Fame. “The opposite of stress is death.”
The scientist divided stress into mobilizing (useful), or eustress, and destructive (negative) – distress. The duration of stress can also be divided into acute (shock) and chronic. Both good and bad stress use up the body’s energy. “The physical reactions of a mother when she learns that her son fell in battle are the same as when she hears later that the first message was a mistake and that he is still alive and well,” Cellier said.
“But the rats were dying!”, one can object to this. Yes, but the stress that lab animals experience is nothing like the stress that humans experience in everyday life. The Day of Experimental Animals consists of various kinds of serious tests, of which current and starvation are the most innocent.
Mikhail Zelko:
“Eustress, that is, stress that the body is able to actively cope with, increases its adaptive potential. A good example is physical activity, getting used to which, the body becomes stronger and more resilient, a similar phenomenon can also be observed with moderate psycho-emotional stress, increasing stress resistance.
In addition to the obvious options for increasing resistance to the same stressor when it is repeated, there is also the phenomenon of cross-adaptation to different stressors. For example, due to the nonspecificity of the stress response at the molecular level, hypoxic or thermal training can improve physical and athletic performance, stress resistance, and prevent the development of a number of post-stress disorders. Quite a few variants of such cross-adaptation have been identified, and the phenomenon can potentially be used as training or therapeutic effects, which has recently been actively studied all over the world, including in our laboratory.”
Even during pregnancy, one of the most vulnerable periods in life, stress is not always harmful. In 2011, scientists from the University of California analyzed more than hundreds of studies and found that only extremely difficult situations (for example, terrorist attack, fire, loss of property, death of loved ones) increase the risk of preterm birth. Ordinary everyday stress, which we face every day, does not cause such consequences. Moreover, some level of stress is even good for the child. Scientists from Johns Hopkins University have concluded that women who experience strong, but not extreme stress during pregnancy, children are born with more developed brains and better heart rates. The stress hormones of the mother, as it were, “teach” the nervous system of the fetus to adapt. Researchers have linked maternal stress to accelerated neurological maturation.
What happens to the bodyduring stress
The stress response activates different biological systems, and they form different behavioral strategies. The hypothalamus activates a hormone that affects the pituitary gland, then the adrenal glands release cortisol and adrenaline into the blood – adrenaline makes the heart beat faster to provide more oxygen to the brain and muscles, and cortisol raises blood sugar levels for energy. At the same time, cortisol inhibits the activity of the intestines and reduces the activity of the digestive and reproductive systems. This physiological response to stress provides a person with exceptional physical and intellectual abilities in crisis situations.
Mikhail Zenko:
“Cortisol-activated glucocorticoid receptors bind to specific regions of DNA and affect the functioning of a large number of genes that control metabolism and all of the processes listed above. Glycogen stores in the liver are processed into fast energy resources – glucose, the main consumer of which is the brain. The circulatory system of “important organs” increases blood flow in them and distributes energy resources more efficiently, blood supply and metabolism in other organs, on the contrary, decreases during a stress response.
If the body’s response was sufficient, then the second phase, resistance or resistance, begins, when the body is able to effectively cope with the effects of the stressor without depleting important resources. Such stress is eustress, that is, stress that makes the body stronger or more adaptable.
Such a redistribution of resources allows you to quickly respond to changing conditions, however, if stressful effects begin to be long-term, chronic, in nature, or exceed the possibilities of adaptation in strength, exhaustion or distress begins. For example, prolonged suppression of the immune system by cortisol leads to the development of infectious diseases, which in everyday experience is expressed in “colds after hypothermia.”
A cocktail of endorphins, adrenaline, testosterone and dopamine can look quite attractive to the body. That is why some people call it consciously – they jump with a parachute, dive to the depths, conquer mountain peaks. Stress gives them a pleasant excitement, makes them feel better. Every trouble is a stress inoculation. That is why stress training is a must in the programs of astronauts, athletes, and law enforcement officers.
How to make friends with stress
In 1975, psychologist Salvatore Maddi of the University of Chicago began a long-term study of the effects of stress on workers at the Illinois Bell telephone company. In 1981, she survived the crisis and was forced to lay off half of the employees. Some of the remaining employees began to show symptoms of illness and depression, while others, on the contrary, felt full of energy, rejoiced at the opportunities.
Muddy, who has been watching his wards for more than a year, has accumulated a whole file of their personal data. He and his colleagues tried to understand what caused the difference in response to stress. It turned out that people who feel great under stress believed that any stress is an opportunity for learning and were not inclined to catastrophize everything. They took active steps, maintained personal connections, showed less hostility, and took care of themselves. Muddy called this set of beliefs and strategies “resilience,” which he defined as “the courage to turn stress for good.”
Mikhail Zenko:
“Distress differs from eustress primarily in that it exceeds the adaptive capabilities of a particular organism and leads to a phase of stress exhaustion, which is expressed in illness and, in extreme cases, death of the individual. At all levels below the psychological, that is, at the level of hormones and cells, stress has no modality. However, it exists at the level of emotions, and it is the emotional perception of the stressor that seems to be an important point influencing the subsequent response.
One of the most common models of depression in neuroscience is the “learned helplessness” model, when, due to chronic stress, the body ceases to perceive any stressors as something that it can cope with – this leads to the development of a full-fledged mental illness, depression. The perception of stress as something to be dealt with, on the contrary, is adaptive in nature and, apparently, strongly influences the outcome of events. The reaction determines whether we go in the direction of eu- or distress.
The second important point is to increase the reserve of “forces” of adaptation, which is achieved through regular repetitions or training with some kind of stressor. The human body can get used to or adapt to an extremely wide variety of conditions that have not even been encountered before, the main points are regularity, constancy and emotional perception.