The phenomenon has intrigued both scientists and doctors for decades, who seek to unravel the secrets behind this apparent invulnerability.
Table of Contents
- The phenomenon has intrigued both scientists and doctors for decades, who seek to unravel the secrets behind this apparent invulnerability.
- immune system
- Genetics: the factor we do not choose
- The lifestyle
- The microbiome: invisible ally
- Stress and the mind: powerful connections
- Controlled exposure: training the system
- Environmental factors: the environment matters
- Age and immunity
- Do they really never get sick?
Los Angeles, December 27 (LaOpinión).- In every office, in every family, in every social circle there is that person who seems immune to the colds seasonal, which goes through epidemics of gripe without a sneeze and who keeps a enviable health while others fall one after another before virus y bacteria. While most people experience between two and four colds a year, this select group seems armored against the diseases most common.
The phenomenon has intrigued both scientists and doctorswho seek to unravel the secrets behind this apparent invulnerability.
The first key to understanding those who rarely get sick is in their immune system. Not all defense systems are the same.
immune system
Some individuals possess what immunologists call a “robust innate immune response,” an extraordinarily efficient first line of defense that neutralizes pathogens before they can establish an infection.
Dr. Philip Goulder, professor of immunology at the University of Oxford, explains that these people have particularly active natural killer (NK) cells and macrophages, capable of detecting and eliminating threats with above-average speed and efficiency. “It’s like having exceptionally alert security guards at the front doors of your body,” he notes.
Furthermore, the diversity of the T cell repertoire plays a fundamental role. Those with a greater variety of these cells can recognize and respond to a broader spectrum of pathogens, giving them a significant advantage in the battle against infections.
Genetics: the factor we do not choose
Genes contribute approximately 20 percent to 40 percent to the ability of the immune system, according to various scientific studies. Certain genetic variants are associated with stronger immune responses. For example, variations in the HLA (human leukocyte antigen) genes, which help the immune system distinguish between the body’s own proteins and foreign ones, can make the difference between getting sick frequently or rarely.
Recent research has identified specific mutations that appear to confer resistance to certain diseases. The most famous case is the CCR5-Delta 32 mutation, which offers resistance to HIV. Studies on people who never contracted COVID-19 despite being highly exposed have revealed genetic variants in genes related to the interferon response, a key molecule in antiviral defense.
However, genetics is not destiny. As Dr Janet Lord, director of the Institute of Inflammation and Aging at the University of Birmingham, says: “Your genes load the gun, but your lifestyle pulls the trigger.”
The lifestyle
Daily habits have a considerable influence on the body’s ability to resist disease. Quality sleep emerges as one of the most critical factors. During deep sleep, the body produces cytokines, proteins that fight infection and inflammation. People who sleep less than six hours a night are up to four times more likely to catch a cold than those who sleep seven hours or more.
Nutrition constitutes another fundamental pillar. A diet rich in fruits, vegetables, lean proteins, and healthy fats provides the essential nutrients the immune system needs to function optimally. Deficiency of vitamins D, C, zinc and selenium has been linked to increased susceptibility to infections.
Regular moderate exercise also strengthens the body’s defenses by promoting the circulation of immune cells and reducing chronic inflammation. Interestingly, extreme exercise can have the opposite effect, temporarily weakening the immune system.
The microbiome: invisible ally
In recent years, science has discovered that the gut microbiome, that ecosystem of trillions of microorganisms that inhabit our digestive tract, plays a crucial role in immune health. People with diverse and balanced microbiomes tend to have more robust immune systems.
These microorganisms not only help digest food, but train the immune system, teaching it to distinguish between real threats and false alarms. A healthy microbiome can prevent both infections and autoimmune diseases caused by overactive immune systems.
Early exposure to various microbes, especially during childhood, appears to program the immune system for life. The “hygiene hypothesis” suggests that overly sterile environments may deprive the immune system of necessary training, paradoxically resulting in increased susceptibility to disease.
Stress and the mind: powerful connections
The connection between the mind and the immune system is deeper than many imagine. Chronic stress raises levels of cortisol, a hormone that, in excess, suppresses immune function. People who manage stress effectively, through meditation, exercise, or strong social connections, maintain more competent immune systems.
Studies on longevity in populations such as Okinawa, Japan, or Blue Zones around the world reveal that a sense of purpose, strong community relationships, and a positive attitude toward life correlate with better general health and lower frequency of illness.
Loneliness and social isolation, on the other hand, have immunological effects comparable to smoking or obesity, increasing vulnerability to infections and chronic diseases.
Controlled exposure: training the system
Paradoxically, some level of exposure to pathogens can be beneficial. Every time the immune system confronts and defeats an invader, it develops immunological memory, becoming more efficient. People who work in environments with greater controlled microbial exposure, such as teachers or healthcare personnel, often develop more robust immunity over time.
This is the basis of vaccination: training the immune system without the risks of full disease. People who keep their vaccination schedules up to date significantly reduce their risk of serious illness.
Environmental factors: the environment matters
Air quality, access to clean water, ambient temperature and humidity influence the ability of pathogens to spread and the effectiveness of our defenses. People who live in environments with good ventilation and moderate humidity are less likely to contract respiratory infections.
Exposure to nature also appears to benefit the immune system. Japanese studies on “shinrin-yoku” or forest bathing show that spending time in natural spaces increases the activity of NK cells and reduces markers of inflammation.
Age and immunity
Although it is true that the immune system tends to weaken with age, a phenomenon known as immunosenescence, this is neither inevitable nor uniform. Some older people maintain remarkably robust immune systems, often due to a combination of good genetics, healthy lifestyle and positive mental attitude.
Centenarians studied by longevity researchers frequently show immunological profiles that defy their chronological age, with low levels of inflammation and preserved adaptive immune responses.
Do they really never get sick?
It is important to clarify that even people apparently immune to diseases probably do get infected occasionally, but their immune systems are so efficient that they neutralize infections before they produce noticeable symptoms. They experience what doctors call “subclinical infections”: their bodies fight pathogens silently, without them noticing.
Furthermore, the perception of “never getting sick” may be partially selective. These people may have a better tolerance for mild symptoms or recover so quickly that they barely register the episode as an illness.
Ultimately, the mystery of those who never get sick lies not in a single miraculous factor, but in the fortunate convergence of favorable genetics, sustained healthy habits, conducive environments and, perhaps, a dash of good luck. Understanding these factors not only satisfies our curiosity, but offers us a map to strengthen our own natural defenses.
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