The link between exercise and immunity
Physical activity is one of the best ways to support our immune systems, but it’s often a fine balancing act when you engage in high-volume or intense training.
Moderate intensity exercise seems to be the sweet spot when it comes to improving immune function, offering the potential to reduce the risk and severity of respiratory viral infections1.
Supporting your immune system
The right exercise type and intensity can also cause changes in immune cells, like antibodies and white blood cells.
While the exact mechanisms are still being researched, these changes may enhance the ability of immune cells to detect and combat an infection.
For example, research2 shows that even short bouts of moderate-intensity exercise can increase the levels of natural killer (NK) cells, which are crucial for destroying infected cells.
The study compared the effects of 15 or 30 minutes of moderate-intensity exercise on the mobilisation of white blood cells, including lymphocytes, monocytes, and granulocytes. The team found that just 15 minutes of exercise at a moderate intensity effectively mobilised the white blood cells into circulation.
This mobilisation is only the first step, as exercise also increases heart rate and dilates blood vessels, which helps circulate the immune cells around your body more effectively. With these cells patrolling your body, they can more effectively detect and start fighting those illness-causing pathogens (bacteria and viruses) earlier.
How exercise helps in lowering inflammation
Regular exercise can also help reduce chronic low-grade inflammation, which is linked to various diseases and can impair immune function. Specifically, exercise promotes the release of anti-inflammatory cytokines (proteins) that can help regulate the immune response3.
In addition, exercise activates the innate immune system – the body's natural, non-specific defence system – to express cytokine production4, which modulates inflammation and the immune response.
Exercise can also have a less direct impact on immunity through its ability to reduce chronic stress, which is known to suppress the immune system. Certain exercises have been shown to lower the levels of stress hormones like cortisol, which may help protect against illness5.
The right exercise
The key to unlocking the immune-boosting benefits of exercise is performing at least 150 minutes of moderate-intensity activities per week3.
Activities like brisk walking, jogging, cycling, swimming, and dancing improve circulation and have been consistently linked to better immune function.
While often focused on muscle building, strength training also contributes to overall health and can indirectly support immunity by reducing inflammation and improving metabolic health.
Activities like yoga, Tai Chi, and Pilates can help reduce stress, which is a significant suppressor of the immune system.
Intense, prolonged exercise
While intense exercise has various health benefits, prolonged sessions lasting over 1.5 hours of high-intensity exercise can temporarily suppress the immune system, leading to a phenomenon called post-exercise immunosuppression (PEIS)6.
PEIS is a physiological response to large training loads or strenuous exercise, which generally happens due to a rise in stress hormones such as adrenaline and cortisol.
As such, if you are looking to boost your immunity this winter, it is recommended that you limit your hard training sessions and engage in more moderate-intensity exercise that supports your immune system, rather than overloads it.
Supplement support to strengthen your immunity
If you do engage in high-volume or intense training, you can support your immune system with a range of vitamins and minerals from well-formulated supplements available at Dis-Chem stores.
Vitamin D plays roles in various bodily systems, including both the innate and adaptive immune responses7. The so-called 'sunshine' vitamin enhances innate cellular immunity by stimulating immune cell expression and helps to maintain cell integrity.
Supplements that boost vitamin D levels and address any deficiency can help to reduce the incidence and severity of viral infections and URTIs8.
A zinc deficiency can increase pro-inflammatory cytokines9 and alters immune function10, making them more susceptible to infection. This trace mineral also has anti-viral properties11.
Vitamin C is a vital nutrient needed to fight infections. Vitamin C acts as an antioxidant, and immune cells called leukocytes require significant amounts to fight infections12. This makes vitamin C a conditionally essential nutrient during illness, which is where supplements can really help. Consuming additional vitamin C can reduce an infection's duration and severity13.
An explosion of research into the immuno-stimulatory properties of probiotics has also emerged over the last decade14. Studies on their effects found that probiotics caused a faster rise in circulating natural immune killer cells to normal pre-exercise resting levels following intense training15. These results indicate that probiotics may help to reverse PEIS.
References:
1. Martin SA, Pence BD, Woods JA. Exercise and respiratory tract viral infections. Exerc Sport Sci Rev. 2009 Oct;37(4):157-64. doi: 10.1097/JES.0b013e3181b7b57b. PMID: 19955864; PMCID: PMC2803113.
2. Ali, Kais; Hunt, Rebekah; Banh, Rachel; McBride, Lynnsie; Bolden, McArthur III; Laurea, Karl; and LaVoy, Emily C. (2024) "The Effects of 15 Minutes vs. 30 Minutes of Moderate Intensity Exercise on Lymphocytes, Monocytes and Granulocytes," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 16, Article 184. https://digitalcommons.wku.edu/ijesab/vol2/iss16/184.
3. Scheffer DDL, Latini A. Exercise-induced immune system response: Anti-inflammatory status on peripheral and central organs. Biochim Biophys Acta Mol Basis Dis. 2020 Oct 1;1866(10):165823. doi: 10.1016/j.bbadis.2020.165823. Epub 2020 Apr 29. PMID: 32360589; PMCID: PMC7188661.
4. Docherty, S., Harley, R., McAuley, J.J. et al. The effect of exercise on cytokines: implications for musculoskeletal health: a narrative review. BMC Sports Sci Med Rehabil 14, 5 (2022). https://doi.org/10.1186/s13102-022-00397-2.
5. De Nys L, Anderson K, Ofosu EF, Ryde GC, Connelly J, Whittaker AC. The effects of physical activity on cortisol and sleep: A systematic review and meta-analysis. Psychoneuroendocrinology. 2022 Sep;143:105843. doi: 10.1016/j.psyneuen.2022.105843. Epub 2022 Jun 24. PMID: 35777076.
6. Gleeson M. Immune system adaptation in elite athletes. Curr Opin Clin Nutr Metab Care. 2006 Nov;9(6):659-65. doi: 10.1097/01.mco.0000247476.02650.18. PMID: 17053416.
7. Hewison M. Vitamin D and innate and adaptive immunity. Vitam Horm. 2011;86:23-62. doi: 10.1016/B978-0-12-386960-9.00002-2. PMID: 21419266.
8. Grant WB, Lahore H, McDonnell SL, Baggerly CA, French CB, Aliano JL, Bhattoa HP. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients. 2020 Apr 2;12(4):988. doi: 10.3390/nu12040988. PMID: 32252338; PMCID: PMC7231123.
9. Foster M, Samman S. Zinc and regulation of inflammatory cytokines: implications for cardiometabolic disease. Nutrients. 2012 Jul;4(7):676-94. doi: 10.3390/nu4070676. Epub 2012 Jul 4. PMID: 22852057; PMCID: PMC3407988.
10. Shankar AH, Prasad AS. Zinc and immune function: the biological basis of altered resistance to infection. Am J Clin Nutr. 1998 Aug;68(2 Suppl):447S-463S. doi: 10.1093/ajcn/68.2.447S. PMID: 9701160.
11. Read SA, Obeid S, Ahlenstiel C, Ahlenstiel G. The Role of Zinc in Antiviral Immunity. Adv Nutr. 2019 Jul 1;10(4):696-710. doi: 10.1093/advances/nmz013. PMID: 31305906; PMCID: PMC6628855.
12. Mitmesser SH, Ye Q, Evans M, Combs M. Determination of plasma and leukocyte vitamin C concentrations in a randomized, double-blind, placebo-controlled trial with Ester-C(®). Springerplus. 2016 Jul 25;5(1):1161. doi: 10.1186/s40064-016-2605-7. PMID: 27512620; PMCID: PMC4960105.
13. Hemilä H, Chalker E. Vitamin C reduces the severity of common colds: a meta-analysis. BMC Public Health. 2023 Dec 11;23(1):2468. doi: 10.1186/s12889-023-17229-8. PMID: 38082300; PMCID: PMC10712193.
14. Mazziotta C, Tognon M, Martini F, Torreggiani E, Rotondo JC. Probiotics Mechanism of Action on Immune Cells and Beneficial Effects on Human Health. Cells. 2023 Jan 2;12(1):184. doi: 10.3390/cells12010184. PMID: 36611977; PMCID: PMC9818925.
15. Aziz N, Bonavida B. Activation of Natural Killer Cells by Probiotics. For Immunopathol Dis Therap. 2016;7(1-2):41-55. doi: 10.1615/ForumImmunDisTher.2016017095. PMID: 28616355; PMCID: PMC5467532.
