This question is about Cycling
Cycling is a low-impact exercise that can boost and strengthen the immune system. Research suggests that cycling helps to reduce immunosenescence, which is the change in the immune system associated with age [ 1 2 3
However, not all forms of exercise are created equal when it comes to promoting immunity. Recent studies have also found that repeated strenuous exercise may temporarily reduce immune function, making you more susceptible to illness after a heavy training session [ 4 3
[1] Duggal, N. A., Pollock, R. D., Lazarus, N. R., Harridge, S., & Lord, J. M. (2018). Major features of immunosenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood. Aging cell, 17(2), e12750. https://doi.org/10.1111/acel.12750
[2] Aw, D., Silva, A. B., & Palmer, D. B. (2007). Immunosenescence: emerging challenges for an ageing population. Immunology, 120(4), 435–446. https://doi.org/10.1111/j.1365-2567.2007.02555.x
[3] How to boost your immune system. Harvard Health. (2021, February 15). https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system.
[4] Simpson, R. J., Campbell, J. P., Gleeson, M., Krüger, K., Nieman, D. C., Pyne, D. B., Turner, J. E., & Walsh, N. P. (2020). Can exercise affect immune function to increase susceptibility to infection?. Exercise immunology review, 26, 8–22.