Cellular innate and adaptive immunity are affected by chronic exercise: implication of the cannabinergic system

The impact of performing exercise on the immune system presents contrasting effects on health when performed at different intensities. In addition, the consequences of performing chronic exercise have not been sufficiently studied in contrast to the effects of acute bouts of exercise. Our findings shed light on the effects that chronic exercise elicits on several immune cell subpopulations, from the innate to the adaptive immunity. For this study male Wistar rats performed treadmill running 5 times a week for a period of 10 weeks, speed and duration in each exercise bout was gradually increased until reaching 40 minutes at 15 m/min. Our results showed a significant decrease in lymphocyte subpopulations (CD4+, Tγδ, and CD45 RA+ cells) and also indicate an alteration in the cannabinoid receptors expression in some of these cells subsets. Although functional assays did not reveal any variation in total immunoglobulin production or NK cells cytotoxic activity, proliferative capability of total splenocytes increased in trained rats. Our results further support the notion that exercise affects the immunological system and extends the description of underlying mechanisms mediating such effects. Altogether, our results contribute to the understanding of the benefits of exercise on the practitioner’s general health.