Aerobic training increases the stimulated percentage of CD4 super(+)CD25 super(+) in older men but not older women

The purpose of the present study was to determine whether 12months of moderate intensity cycling would increase the expression of IL-2 (CD25 super(+)) receptors in T helper (CD4 super(+)) lymphocytes in men and women aged 65-75years. Fourteen men and 10 women completed 52weeks of moderate intensity cycling (60% VO sub(2)peak). Subjects trained (TR) three times per week for 45min per session. Eight age-matched untrained (UT) male and eight UT female subjects acted as controls. Resting blood samples were taken from TR and UT subjects every 4weeks. Leukocyte concentration was measured using a full blood count. PHA-stimulated CD4 super(+) lymphocytes were analysed for changes in the expression of CD25 super(+), by flow cytometry. Training significantly increased VO sub(2peak) (lmin super(-1), mlkg super(-1)min super(-1)) in male (+14.3, +16%) and female (+16.7, +27.8%) groups. The TR male group showed a significantly lower percentage of CD4 super(+)CD25 super(+) than the male UT in January but the TR male percentage was significantly higher than the UT male group during February, March, April, May, June, September B and December. The female TR group showed a significantly higher percentage CD4 super(+)CD25 super(+) than the female UT only during July. There were also significant sequential monthly changes in the percentage of CD4 super(+)CD25 super(+) for male and female UT and TR groups. Significant increases in the percentage of CD4 super(+)CD25 super(+) in the male TR group suggest training-enhanced lymphocyte mitogenic responsiveness. Moderate intensity long-term training may increase the recruitment of active memory CD4 super(+)CD25 super(+) in men rather than women.