Is immunosenescence influenced by our lifetime “dose” of exercise?

Abstract

The age-associated decline in immune function, referred to as immunosenescence, is well characterised within the adaptive immune system, and in particular, among T cells. Hallmarks of immunosenescence measured in the T cell pool, include low numbers and proportions of naïve cells, high numbers and proportions of late-stage differentiated effector memory cells, poor proliferative responses to mitogens, and a CD4:CD8 ratio <1.0. These changes are largely driven by infection with Cytomegalovirus, which has been directly linked with increased inflammatory activity, poor responses to vaccination, frailty, accelerated cognitive decline, and early mortality. It has been suggested however, that exercise might exert an anti-immunosenescence effect, perhaps delaying the onset of immunological ageing or even rejuvenating aged immune profiles. This theory has been developed on the basis of evidence that exercise is a powerful stimulus of immune function. For example, in vivo antibody responses to novel antigens can be improved with just minutes of exercise undertaken at the time of vaccination. Further, lymphocyte immune-surveillance, whereby cells search tissues for antigens derived from viruses, bacteria, or malignant transformation, is thought to be facilitated by the transient lymphocytosis and subsequent lymphocytopenia induced by exercise bouts. Moreover, some forms of exercise are anti-inflammatory, and if repeated regularly over the lifespan, there is a lower morbidity and mortality from diseases with an immunological and inflammatory aetiology. The aim of this article is to discuss recent theories for how exercise might influence T cell immunosenescence, exploring themes in the context of hotly debated issues in immunology.

There is limited existing evidence to support the common assumption that strenuous endurance exercise bouts impair immune competency

“…In this hypothesis, it is proposed that exercise mobilizes senescent T cells into blood, which home to tissues where some undergo apoptosis. Naïve T cells refill the 'immunological space' that has been created, due to exercise-induced thymopoiesis or extrathymic development, perhaps in response to IL-7 released from contracting skeletal muscle [18,19].…”

A Peripheral Blood Transcriptome Biomarker Test to Diagnose Functional Recovery Potential in Advanced Heart Failure

“…We postulate that reduced FRP is related to the age-associated decline in immune function, referred to as immunosenescence, is well-characterized within the adaptive immune system, and in particular, among T cells. Exercise might exert an anti-immunosenescence effect, perhaps delaying the onset of immunological aging or even rejuvenating aged immune profiles, based on evidence that exercise is a powerful stimulus of immune function [127,128]. It is likely that the cumulative effect of behavior over a substantial period of the lifespan influences the rate of immunosenescence [127,129].…”

Does Regular Exercise Counter T Cell Immunosenescence Reducing the Risk of Developing Cancer and Promoting Successful Treatment of Malignancies?

“…However, individuals who take part in regular very prolonged or extreme aerobic exercise over their lifetime may exhibit changes in the T cell pool that are indicative of exaggerated immunosenescence [4]. It seems that both the anti-immunosenescence effects of typical aerobic exercise training and the proimmunosenescence effects of extremely prolonged endurance training are most prominent in young individuals.…”