How to Exercise to Strengthen the Immune System.
Exercise immunology is a relatively fresh field of study with 90% of its papers being published post the 1990s. While it has been present since the 1900s, a lack of equipment impeded the field of study.
At a time like now, it is vital we understand the link between exercise and the immune system.
However, keep in mind that no change is instantaneous, it will take time for a change in physical fitness and an increase in exercise to provide long-term improvement in immune system capability.
Benefits associated with exercise and the immune system
Across the research, it has consistently been shown that moderate physical activity leads to improved immunosurveillance.
Immunosurveillance can be described as the process by which the immune system’s cells look for foreign pathogens like bacteria and cancerous cells. It allows the recognition and destruction of transformer cells prior to them growing into tumors.
In brief bouts of moderate exercise, NK cells and CD8 T lymphocytes which exhibit a high level of cytotoxicity are mobilized. This is critical to the activity of the immune system.
Furthermore, recirculation occurs of various immunoglobulins, anti-inflammatory cytokines, NK cells, neutrophils, cytotoxic T cells, and immature B cells.
Good conditioning, something which comes from exercising, has been shown to result in higher levels of T-lymphocyte and NK cell function.
All these come together to result in a lower illness rate.
Why intensive long-duration endurance training workouts isn’t the way to go
According to popularly referenced meta-analysis, intensive long-term exercise is associated with transient immune disturbances, oxidative stress, inflammation, and a general increase in disease risk.
This means that exercise of a higher intensity when carried for an interminable period of time can affect your immune system negatively.
Data has suggested that the metabolic capacity of your immune cells decreases during the period post-exercise, which may cause transient immune system dysfunction.
This suggests that post a period of high-intensity exercise, your immune system gets compromised.
Various studies have shown that a high volume of aerobic/anaerobic endurance training can significantly increase your chances of illness.
In a study on participants of the Los Angeles Marathon, it was found that 13% of participants fell sick during the week post the marathon. They compared this to a group of control runners out of which 2% of runners fell sick in the same time period.
Furthermore, the same study found that those who ran more than 96km/week vs. less than 32km/week doubled their odds for illness.
Ever since the 1980s, researchers have found a strong correlation between the prevalence of upper respiratory tract infection and running at a high volume.
In the above chart, you can note a significant difference between the immune response of a marathon and a bout of walking.
Both of them have very different effects on the immune system. Taking a look at a marathon, you can see a nearly opposite effect on the immune system compared to walking. The marathon negatively affects the immune system in the short term and hence you can see an enormous difference in all three facets of immunity being discussed in the diagram.
These are some negatives associated with high volume intensive endurance work.
The correct approach to exercise for optimal immune health
For optimal immune health, we should use moderate exercise. This will lead to a higher stimulation of certain subtypes of immune cells.
From this exercise, anti-pathogen activity is increased and there will be an increase in recirculation of various immune cells.
Scientists have observed a J curve relationship between infection risk and the intensity of exercise. Through this, you can conclude that the correct approach for maximal immune health is moderate exercise.
Indirect and direct implications
While exercise plays a role in the overall function of the immune system, the role it plays is not the biggest role there is. Other things like BMI play a large role in the immune system function.
Exercise can reduce the BMI of those who are of a high BMI which will lead to an increase in immune system health because of a reduced BMI.
A high body fat percentage is another risk factor in immune system health and consistent exercise can reduce this risk.
Exercise can also directly improve the count of anti-inflammatory cytokines (good) and enhance the circulation of various cells and neutrophils present in the immune system.
To put this all simply, understand the following statements
- Excessive exercise will negatively affect your immune system
- Good physical fitness will enhance your immune system function
- Exercise needs to be a consistent part of your life to reap benefits
A point you must note is that while some intensities of exercise may compromise your immune system for the short term, in the long run, better fitness will lead to improvements in the immune system.
The opposite is applicable too wherein if you are doing high-intensity exercise too much and for too long, you will probably compromise your immune system in the long run.
One thing you must ensure is that exercise should be a consistent part of your life if you want to reap benefits. Exercising as soon as a global pandemic strikes probably won’t give you the requisite gains in the immune system.
Finally, realize that exercise is just one thing that affects your immune system. Your immune system is dependent on a host of other factors, with some that are more important than exercise for a stronger immune system.
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