Why a little stress is good for your health

Stress is one of the great enemies of modern health. It is linked to cardiovascular and metabolic diseases, anxiety and depression, cognitive decline, and immune disorders. When it is high and becomes chronic, its impact can be devastating. However, not all stress is harmful, as is often thought. In certain doses and contexts, it can do the exact opposite. Healthy stress can become a biological tool for growth, learning, and adaptation, as neuroscientist Helen Thomson explains in a paper published in New Scientist.

This idea is not new. During the 1970s, endocrinologist Hans Selye, considered one of the fathers of modern stress research, distinguished between negative stress, which he called distress, and healthy stress, or eustress. The former wears us down, while the latter stimulates us. Stress is a physiological reaction of the body and brain that is triggered when we detect a potential threat, whether physical or psychological. It is an extraordinarily sophisticated survival response. In a matter of seconds, the sympathetic nervous system releases adrenaline.

This hormone causes the heart rate to increase, breathing to accelerate, and blood to be redistributed to muscles and other essential organs. Shortly thereafter, cortisol appears, mobilizing the energy and resources needed for the body to face the challenge. At the same time, the brain focuses on the source of the possible threat, while restricting other processes, such as digestion, the immune response, or certain complex cognitive functions. It is an adaptive mechanism that, when the threat is real and specific, has allowed us to survive for hundreds of thousands of years. The problem, however, arises when this alarm system becomes permanently activated.When the alarm is permanent

Chronic stress keeps cortisol levels high, which can end up harming the body's entire physiology. At the same time, the brain becomes less sensitive to the mechanisms that should allow this response to stop when the alarm situation is over, which increases the risk of developing physical and mental pathologies. It is at this point that stress ceases to be useful and becomes toxic.

But the total absence of stress is also not beneficial. Several investigations have observed that people who have had to face some moderate difficulties throughout their lives, such as a breakup, an unwanted job change, or a minor injury, often show better mental health and greater resilience than those who have never experienced any significant adversity. It is what some psychologists call "stress inoculation." Small doses of difficulty train the brain and nervous system to better cope with future challenges. It is like a kind of "psychological vaccine".The key, says Thomson, is not to eliminate stress, but to find the right dose. One of the best examples is physical exercise. When we do intense activity, the body experiences a situation of biological stress: stress hormones increase, muscle micro-tears occur, and a lot of energy is consumed. This "controlled aggression" activates repair and adaptation mechanisms that make the organism stronger. The body rebuilds itself better than it was before.

However, even this beneficial stress has limits. Too much exercise can also be harmful. Extreme training has been shown to increase cardiovascular risk and general wear and tear on the body. The same applies to other forms of physical stress, such as heat exposure. Saunas, for example, activate cellular repair proteins and reduce inflammatory processes. But excessively high temperatures or prolonged exposure can have the opposite effect.Regarding cognitive stress, unfortunately all too common in today's society, it also follows this logic. This is why chronic mental stress favors the manifestation not only of psychological exhaustion, but also of conditions such as anxiety and depression, which harm mental and physical health. However, it is also true that we often work better under a certain pressure, or eustress, using Hans Selye's term. A tight deadline or a demanding academic challenge can increase concentration, mental speed, and learning. On the other hand, a demand perceived as impossible has the opposite effect, and usually causes blockage, anxiety, and exhaustion.

The difference depends not only on the objective situation, but also on the perception of control we have. Stress is much more detrimental when we experience it as an inevitable imposition. On the other hand, when we voluntarily choose to face a challenge, such as taking on a professional responsibility, the body and brain tend to respond more adaptively. It has been observed that people who perceive the symptoms of stress as a signal of preparation rather than danger, tend to recover faster and perform better. This change in perspective does not eliminate difficulties, but it transforms how the brain processes them. “In a society obsessed with avoiding any discomfort,” Thomson concludes in his work, “this view is almost revolutionary. Perhaps well-being does not consist in living without stress, but in learning to live with the right kind of stress, which activates us without destroying us, challenges us without overwhelming us, and ultimately makes us more resilient”.