Improving Immunity Part 3 - Exercise
Tanner Mackenzie • May 29, 2021
Exercise's Role in Immune Health
In this third installment of Improving Immunity, we will take a closer look at exercise’s effects on immune function. Most of us intuitively know that exercise should improve your immune system function; exercise has positive effects on basically every aspect of human physiology. As more than just curious bystanders to our own health, let’s take a look at exactly how exercise impacts our immunity.
What Effect Does Exercise Have on Our Immune Systems?
The effects of exercise on our immune function are very much related to how long and how hard we train. Exercising at moderate intensity for up to an hour increases a whole host of
immune activity, including anti-inflammatory molecules and antibodies. Prolonged exercise at high intensity can do precisely the opposite, suppressing immune function. With prolonged, intense exercise you see inflammation, muscle damage, and stress. Although much of what we know about how exercise affects our immune system comes from research done from 1990 onwards, as early as 1902 we already knew this basic principle of “overexertion”. A study by
Larrabee showed that white blood cell counts in Boston marathon runners were similar to those with certain diseases.
Even though these acute effects are short-lived, over time they can enhance, or damage, our body’s functionality. For example, regular, moderate exercise improves immunosurveillance (recognizing bacteria, viruses and cancer cells) over time. Further, all-cause mortality (or your chance of dying regardless of cause) decreases sharply with even a small amount of regular exercise, then increases sharply at the highest levels of activity. This corroborates the idea of a compromised immune system with too little (or too much!) exercise. The middle is the way!
How Do These Effects Benefit Us?
Aside from improved immunosurveillance, regular exercise can also reduce inflammation (even though it increases it acutely) and
reduce illness! The short-term effects of exercise training can, over time, positively impact
tumorigenesis (cancer),
atherosclerosis (heart disease), and other diseases. Following the overexertion principle introduced earlier, there are correlations between long, intense exercise and increased risk for illness such as upper respiratory tract infection (URTI). Take a look at the graph below comparing risk of URTI amongst sedentary, active, and very active individuals.
Adapted from
Nieman
How Does Exercise Improve Longevity Related to Immune Function?
Aside from all the short- and long-term benefits we’ve already discussed, working out has been shown to confer benefits to immune function no matter how old you get! When comparing sedentary against active elderly men and women, active individuals tend to have greater white blood cell function and reduced illness! There are a great number of studies that indicate that immunosenescence, or a dysfunctional immune system as a function of age, can be staved off by regular exercise.
All in all, let’s keep doing what we all know how to do! Train, get outside, walk, be active! And don’t forget, when your body tells you to slow down or take a break, you should listen. Your immune system will thank you!
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