Circulating mononuclear cell numbers and function during intense exercise and recovery

Abstract

To investigate the effect of intense exercise on immune function, 12 healthy males (26 +/- 1 yr) underwent cycle exercise to exhaustion at 80% maximum work load. One hour later, six of the subjects underwent a second identical bout. Blood was drawn preexercise (C), at exhaustion (Ex-1, Ex-2), and at 1 h of recovery (Rec-1, Rec-2). At Ex-1 and Ex-2, total leukocytes (monocytes, neutrophils, and lymphocytes) increased significantly (P less than 0.05), and all returned to C levels by Rec-1 except lymphocytes, which were lower than at C. At Rec-2 total leukocytes remained higher (P less than 0.05) than at C, primarily because of elevated neutrophil counts. Phenotype analysis indicated a 2.5-fold increase in CD16+ (natural killer) cells at Ex-1 and a decrease primarily in CD4+ (T-helper) cells. All phenotype changes returned to C levels at Rec-1. At Ex-1 the in vitro mitogenic response to concanavalin A, phorbol myristate acetate + ionomycin, phytohemagglutinin, and pokeweed mitogen decreased (P less than 0.05) but returned to levels not different from C at Rec-1. Both the in vitro percent specific lysis of a target natural killer cell (K562) and the lytic activity per cell increased (P less than 0.05) in peripheral mononuclear cells at Ex-1, returning to C levels at Rec-1. The total leukocyte counts with exercise were significantly correlated with plasma epinephrine concentration, and a causal effect is thus possible. Such acute changes in numbers and function of circulating cells of the immune system may possibly have functional and clinical correlates.

Leukocyte subsets and neutrophil function after short-term spaceflight

“…Although plasma catecholamines (which are difficult to obtain) were not measured in this study, these results are consistent with previous data showing elevated plasma catecholamines after spaceflight [12]. Elevated neutrophil counts have also been consistently observed after intense exercise [29][30][31][32] and after epinephrine injections [32][33][34]. Significant decreases in eosinophils are also characteristically observed in response to increased epinephrine levels.…”

Effects of Endurance Training on Selected Parameters of Immune Function in Elderly Women

“…Prior to training, the post-exercise value was significantly elevated pre-training and it returned to baseline within 2 h. This pattern of elevation and return to baseline is consistent with other studies on both the elderly and the young [8,32,33].…”

“…The most profound changes occur in the immunoregulatory T cells, and an age-associated decrease in the proliferative response of T cells to mitogen has been documented [6,7]. Additionally, endurance exercise has been shown to result in suppression of lymphocyte proliferation during or immediately following exercise in both young and elderly humans [8][9][10][11][12][13]; yet, endurance exercise is often recommended to reduce the risk of cardiovascular disease, particularly in the elderly. Furthermore, after a bout of intense exercise, natural cell-mediated cytotoxicity (NCMC) has been shown to decrease below resting levels, resulting in what has been termed an 'open window' for infectious agents [14].…”

Natural killer cells responsiveness to physical exercise: A brief review

“…In fact, in subjects of the above experiment, 60 min bicycle exercise at 80% of the VO 2max induced a significantly higher increase in catecholamines and in peripheral blood NK cells than 60 min back-muscle training up to 29% of V O2max . Both moderate exercise (45 min at 60% V O2max ) in women and intense exercise (80% V O2max up to exhaustion) in men showed a workload related increase in NK cells associated with a correspondingly high increase in plasma catecholamines [67]. All the above mentioned observations suggest a catecholamine-dependent increase in both concentration and percentage of NK cells when workload increases progressively up to reach the VO 2-AT .…”

“…Moreover, the increase in epinephrine due to 60 min of bicycle ergometer at 75% of VO 2max and the increase in epinephrine in the same subjects due to its infusion up to reach plasma concentrations comparable with those seen during exercise, induced a comparable increase in NK (CD16+) cells concentration in the peripheral blood which, however, dropped below basal levels 2 h afterward. Even though a positive relationship between an exercise induced increase in NK cell numbers and activity and corresponding rises in blood catecholamines seems to be demonstrated [62,66,67], Mackinnon [26] pointed out that the effects of exercise-dependent increasing blood catecholamines on NK cells number and concentration depend on differences in muscle group activation, intensity and duration of exercise. In fact, in subjects of the above experiment, 60 min bicycle exercise at 80% of the VO 2max induced a significantly higher increase in catecholamines and in peripheral blood NK cells than 60 min back-muscle training up to 29% of V O2max .…”