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
2]. In general, regular exercise helps maintain body weight, lowers blood pressure, and protects against diseases, which support immune health [
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
4]. Cyclists engaging in strenuous training should prioritize rest, recovery, nutrition and hydration, throughout the week to minimize their risk of illness and get the most out of every session [
 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
 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
 How to boost your immune system. Harvard Health. (2021, February 15). https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system.
 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.