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 age-matched control group of ten...