Lifelong training improves anti-inflammatory environment and maintains the number of regulatory T cells in masters athletes

Purpose The purpose of this study was to quantify and characterize peripheral blood regulatory T cells (Tregs), as well as the IL-10 plasma concentration, in Masters athletes at rest and after an acute exhaustive exercise test. Methods Eighteen Masters athletes (self-reported training: 24.6 +/- 1.83 years; 10.27 +/- 0.24 months and 5.45 +/- 0.42 h/week per each month trained) and an agematched control group of ten subjects (that never took part in regular physical training) volunteered for this study. All subjects performed an incremental test to exhaustion on a cycle ergometer. Blood samples were obtained before (Pre), 10 min into recovery (Post), and 1 h after the test (1 h). Results Absolute numbers of Tregs were similar in both groups at rest. Acute exercise induced a significant increase in absolute numbers of Tregs at Post (0.049 +/- 0.021 to 0.056 +/- 0.024 x 10(9)/L, P = 0.029 for Masters; 0.048 +/- 0.017 to 0.058 +/- 0.020 x 10(9)/L, P = 0.037 for control) in both groups. Treg mRNA expression for FoxP3, IL-10, and TGF-beta in sorted Tregs was similar throughout the trials in both groups. Masters athletes showed a higher percentage of subjects expressing the FoxP3 (100% for Masters vs. 78% for Controls, P = 0.038) and TGF-beta (89% for Masters vs. 56% for Controls, P = 0.002) after exercise and a higher plasma IL-10 concentration (15.390 +/- 7.032 for Masters vs. 2.411 +/- 1.117 for control P = 0.001, ES = 2.57) at all time-points. KLRG1 expression in Tregs was unchanged. Conclusion Our findings showed that Masters athletes have elevated anti-inflammatory markers and maintain the number of Tregs, and may be an adaptive response to lifelong training.