During karate fight muscles work at a very high intensity, and their contractions are extremely strong. The movement pattern contains a great number of feints, dodges, frequent changes in movements' tempo and direction, hits and kicks, all of which is highly stressful for athlete's organism, including the immune system. T lymphocyte subsets' distribution and selected cytokines in peripheral blood of three elite karate athletes aged 30 years old (range 21-31 years) with minimum 15 years of training experience were analysed in two experiments: at the beginning of the preparatory phase (a progressive test until exhaustion; an analysis of immune system's selected parameters and cardiorespiratory fitness measures, including VO max, VE, AT, MVV, MET, Rf), and during the start-up period (Karate Championships; an analysis of selected parameters of the immune system). Maximal effort caused an increase in total lymphocyte percentage (p<0.05). A decrease in Th cells in recovery (p<0.05 compared to post-exercise), and an increase in Th naïve cells in recovery (p<0.05) were observed. A significant increase in CD8 central memory cells (p<0.05) was found only after the progressive test, and no changes in both central and effector memory subsets of CD4 cells during the first experiment. An increase (p<0.05) in Treg and Th1 and a decrease (p<0.05) in Th2 cells' distribution during recovery time were found. Additionally, changes (p<0.05) in TNF-α, IL-6, IL-8, IL-10 and IL-12p70 were observed. Post-effort disorder in immune balance activated compensation pathways involving CD4 cells. Treg and Th1 cells seem to be subsets of key importance involved in the anabolic effect of physical effort, at least among karate athletes.