The immune system’s connection with exercise is complicated and poorly understood. The immune system, as the body’s defense against illness, plays a critical part in keeping athletes and the general public healthy on a daily basis. Depending on the type, intensity, and duration of the activity, exercise can have a positive or negative impact on the immune system. Upper respiratory tract infections (URTIs) are widely recognized as a primary cause of poor performance in competitive sports. Many of these competitors had been training hard in the weeks leading up to the competition, which could have lowered their body’s response to infection. URTIs can also strike recreational athletes after periods of intense or unfamiliar exercise. Understanding the influence of exercise on the immune system and its function in maintaining health will lead to improved sports and job performance in the long run.

Innate & Adaptive Immune System

Understanding the foundations of immune system function is required to fully appreciate the intricate interplay between the environment, training, infection, and the immune system. The innate immune system and the adaptive immune system are two complementing defenses that make up the immune system. The innate system is a set of systems that serve as the body’s initial line of defense against infection-causing microorganisms. The skin and mucous membranes, for example, serve as physical barriers to invasion. The skin, however, does not prevent all portals of entry into the human body. The nasal passages and oropharynx, for example, are equipped with specific mucus, enzymes, and complex proteins that begin the breakdown process of undesired bacteria right away.

The adaptive immune system is more complicated and intricate than the innate immune system, which is predictable and mechanical. This is owing to the processes that allow it to recall specific infections and the inflammatory reactions that follow. The adaptive system’s “memory” allows it to recognize a pathogen it has already encountered and develop an immune response swiftly when it is re-exposed.

Three mechanisms are used to carry out this procedure. The first involves identifying antigenic markers, which are proteins on cell surfaces that identify distinct infections. After recognizing a pathogen, the adaptive system can launch a cellular and molecular attack against it. Finally, when the same infections and their associated cell surface proteins attack the body again, the body’s memory system can mount an expedited response to maintain a balanced immune response and maintain health.

Exercise and Immune Function

The impact of exercise and training on the immune system has piqued researchers’ curiosity in recent decades. During this time, many of the generally recognized principles were developed. In this relatively new subject of sports immunology, research is surely active and evolving. Understanding the relationship between exercise and the immune system is becoming increasingly relevant as exercise becomes a cornerstone of health promotion and disease prevention. Furthermore, because URTIs are recognized as a contributing factor to poor sports performance as well as a common cause of job absenteeism, more research is required.


The intensity level of training, according to new study, is a significant predictor of immune system function. After intense training, researchers discovered lower amounts of immunoglobulin A (IgA), an important immunological protein found in mucosal secretions. This secretory immunoglobulin is responsible for fighting infections that enter the upper respiratory system through the mucosal barrier.

The body is more susceptible to URTIs when IgA levels in mucosal secretions are low. IgA levels can drop after as little as one hour of strenuous exercise, which is usually defined as 70 percent to 80 percent of aerobic capacity. While high-intensity exercise may raise the athlete’s risk of URTIs, studies have shown that people who engage in regular, moderate exercise have much greater levels of IgA. This could support the theory that a reasonable quantity of physical activity improves the body’s ability to fight illnesses.


Physical activity also has an impact on two other types of immune cells. Intensive exercise improves the function of natural killer cells, or NK cells. NK cells are part of the body’s innate immune system, and they aid in the battle against viral infections as well as tumor cell elimination. They accomplish this by secreting enzymes that cause apoptosis, or programmed cell death, in the target cells.

The neutrophil, a second critical component of the innate immune system, appears to be less functioning as exercise intensity increases. The neutrophil, commonly known as a white blood cell, is the body’s main cell type for fighting infections and foreign objects. When sedentary people are compared to people who are very active, there is a decline in neutrophil count and function. Increased URTIs are likely due to the suppression of neutrophil activity in athletes who engage in high-intensity training.


More than 100 population-based retrospective studies have been conducted to investigate the relationship between exercise and cancer prevention. Overall, the evidence suggests that those who engage in regular, moderate physical activity have a lower risk of colon and breast cancer. Even low-intensity exercises like mowing the lawn appear to cut cancer risks modestly when compared to sedentary people. In terms of cancer recurrence and cancer-related fatalities, survivors of breast or colon cancer may have a 40% relative risk reduction. Because the particular mechanisms behind the etiology of these advantages are unknown, further study is being conducted in this area.


The elderly are another group whose immune system benefits from frequent physical activity. The human body becomes more susceptible to illnesses as it ages, owing to slower and less effective reactions to attacks, which results in prolonged recovery times. The innate system’s first line of protection, the skin and mucous membranes, can be broken down and porous. T lymphocytes, for example, become less susceptible to activation when they are activated. These cellular inadequacies, when combined with other aging variables including deconditioning, comorbid medical disorders, psychological stress, and dietary deficiencies, result in an immune system that is dysfunctional. Regular physical activity forms an important part of the elderly population’s health maintenance plan. Weight-bearing workouts, for example, can help prevent bone demineralization, which leads to osteoporosis, while also maintaining healthy immunological function.


When selecting how to treat URTIs in the clinical context, knowledge gained from examining athletes’ immune system function before and after intensive training can be employed. Infectious symptoms in athletes should be evaluated in the same way they are in the general population, but with a focus on the unique circumstances of each individual. If an athlete is in the midst of hard training and approaching maximum exertion, antibiotics should be used more aggressively to address possible bacterial causes of URTIs. Most URTIs are viral in nature and do not react to antibiotics, according to common primary care medical practice. Decreased IgA levels in mucus and secretions, on the other hand, may put athletes at risk for bacterial infections.

Recent studies have also shown that several antibiotic families, such as macrolides and fluoroquinolones, may have anti-inflammatory effects in URTIs, which may be responsible for the advantages of these drugs independent of their antibacterial action. Close closeness of sporting teams, drinking from common fluid sources, living in dorms, frequent travel, and time spent in locker rooms may all increase the risk of illness transmission. Furthermore, high levels of stress and anxiety, such as those experienced during competitive sports, have been shown to compromise immune system function, putting the patient-athlete at danger of infection. To avoid misuse of antibiotics, which can propagate bacterial resistance, each athlete’s case should be reviewed independently and attentively. General hygiene practices, such as taking regular showers, not walking barefoot, using timely and suitable skin care, and getting enough sleep and nourishment, cannot be overstated.


In summary, athletes are more susceptible to infections, particularly URTIs, during periods of high-intensity exercise. Mild to moderate aerobic activity, on the other hand, may benefit the immune system and is possibly more suited to the recreational athlete and the general public. As it relates to increased immune system function, it may be sensible to encourage moderate exercise as part of general health maintenance. Athlete education at all levels should emphasize a well-balanced diet, proper sleep, and constructive stress management.

Leave a Reply