Effects of Low-Intensity Brief Exercise and Training on Cell-Mediated Immunity

We investigated the effects of low-intensity brief exercise on lymphocyte functions and plasma cytokine concentrations. Six young sedentary women performed 30-min walking exercise (6 km/h, 50–65% HR max) per day for 3 weeks. Each subject’s peripheral blood was sampled before training, 1 week and 3 weeks after training, and analyzed for natural killer (NK) cell activity, T cell proliferation activity, granzyme B, interleukin-2 (IL-2), IL-6, IL-10, IL-12p40 and interferon.γ (IFN-γ). Lymphocyte functions did not change significantly following training, but plasma concentrations of IL-12p40 decreased significantly. These results suggest that cytokine balance towards significant Th1>Th2 is induced by low-intensity training.