Moderate- to fast-walking improves immunocytes through a positive change of muscle contractility in old women: a pilot study

This study aimed to examine whether compared with a program without walking, intervention programs with three types of walking can improve the muscle property and immunocytes in elderly women. Thirty-two subjects were randomly assigned to control group (CON), slow walking group (SWG), moderate walking group (MWG), and fast walking group (FWG). Three types of walking on treadmill were 30 min a day, 5 days/wk for 12 weeks. Muscle contraction time (Tc), maximum displacement (Dm), and immunocytes were tested by tensiomyography and flow cytometry. After the intervention, FWG had an increasing tendency in the muscle mass compared with other three groups. Tc of biceps femoris (BF) decreased in CON and SWG, while Tc of BF in MWG and FWG (30.58%±23.71%) increased. It was similar in the rectus femoris (RF). Although Dm of BF and RF increased in CON and SWG, those decreased in MWG and FWG. Leucocytes of CON and SWG had a decreasing tendency, those of MWG (9.65%±13.01%) and FWG (13.01%± 13.58%) increased. In the neutrophil, only CON decreased, whereas the three groups showed an increasing tendency. Helper T cell was increased only in FWG (19.61%±19.94%), showing significant differences between groups (P=0.009, η(2)=0.378). Natural killer cell was improved in SWG and MWG but showed a clear increase in FWG (75.76%±63.57%). It might be confirmed that walking for elderly increases the muscle property of the lower legs as they walk faster, which might be expected to improve the immunocytes function.